5-alpha-reductase: 2012-09-02

2012年9月8日星期六

G-protein-coupled receptors in drug discovery: nanosizing using cell-free technologies and molecular biology approaches.

G-protein-coupled receptors in drug discovery: nanosizing using cell-free technologies and molecular biology approaches.

J Biomol Screen. 2005 Dec;10(8):765-79

Authors: Leifert WR, Aloia AL, Bucco O, Glatz RV, McMurchie EJ

Abstract
Signal transduction by G-protein-coupled receptors (GPCRs) underpins a multitude of physiological processes. Ligand recognition by the receptor leads to activation of a generic molecular switch involving heterotrimeric G-proteins and guanine nucleotides. Signal transduction has been studied extensively with both cell-based systems and assays comprising isolated signaling components. Interest and commercial investment in GPCRs in areas such as drug targets, orphan receptors, high throughput screening, biosensors, and so on will focus greater attention on assay development to allow for miniaturization, ultra-high throughput and, eventually, microarray/biochip assay formats. Although cell-based assays are adequate for many GPCRs, it is likely that these formats will limit the development of higher density GPCR assay platforms mandatory for other applications. Stable, robust, cell-free signaling assemblies comprising receptor and appropriate molecular switching components will form the basis of future GPCR assay platforms adaptable for such applications as microarrays. The authors review current cell-free GPCR assay technologies and molecular biological approaches for construction of novel, functional GPCR assays.

PMID: 16234342 [PubMed - indexed for MEDLINE]

NF-kB signaling NF-kappaB signaling pathway NF-kB signaling pathway

Heterotrimeric G-protein complex and G-protein-coupled receptor from a legume (Pisum sativum): role in salinity and heat stress and cross-talk with phospholipase C.

Heterotrimeric G-protein complex and G-protein-coupled receptor from a legume (Pisum sativum): role in salinity and heat stress and cross-talk with phospholipase C.

Plant J. 2007 Aug;51(4):656-69

Authors: Misra S, Wu Y, Venkataraman G, Sopory SK, Tuteja N

Abstract
Heterotrimeric G-proteins transduce signals from activated G-protein-coupled receptors (GPCR) to appropriate downstream effectors and thereby play an important role in signaling. A role of G-proteins in salinity and heat stress tolerance has not heretofore been described. We report isolation of cDNAs of two isoforms of Galpha (Galpha1, 1152 bp; Galpha2, 1152 bp), one Gbeta (1134 bp), two isoforms of Ggamma (Ggamma1, 345 bp; Ggamma2, 303 bp) and a GPCR (1008 bp) from Pisum sativum, and purification of all the encoded recombinant proteins (Galpha, 44 kDa; Gbeta, 41 kDa; Ggamma, 14 kDa; GPCR, 35 kDa). The transcript levels of Galpha and Gbeta were upregulated following NaCl, heat and H(2)O(2) treatments. Protein-protein interaction studies using an in vitro yeast two-hybrid system and in planta co-immunoprecipitation showed that the Galpha subunit interacted with the pea Gbeta subunit and pea phospholipase C (PLCdelta) at the calcium-binding domain (fn1). The GTPase activity of the Galpha subunit increased after interaction with PLCdelta. The GPCR protein interacted with all the subunits of G-proteins and with itself. Transgenic tobacco plants (T(0) and T(1)) constitutively over-expressing Galpha showed tolerance to salinity and heat, while Gbeta-over-expressing plants showed only heat tolerance, as tested by leaf disk senescence assay and germination/growth of T(1) seeds/seedlings. These findings provide direct evidence for a novel role of Galpha and Gbeta subunits in abiotic stress tolerance and possible cross-talk between PLC- and G-protein-mediated signaling pathways.

PMID: 17587233 [PubMed - indexed for MEDLINE]

learn more see here look at here

Hypothalamic dysfunction in obesity.

Hypothalamic dysfunction in obesity.

Proc Nutr Soc. 2012 Sep 6;:1-13

Authors: Williams LM

Abstract
A growing number of studies have shown that a diet high in long chain SFA and/or obesity cause profound changes to the energy balance centres of the hypothalamus which results in the loss of central leptin and insulin sensitivity. Insensitivity to these important anorexigenic messengers of nutritional status perpetuates the development of both obesity and peripheral insulin insensitivity. A high-fat diet induces changes in the hypothalamus that include an increase in markers of oxidative stress, inflammation, endoplasmic reticulum (ER) stress, autophagy defect and changes in the rate of apoptosis and neuronal regeneration. In addition, a number of mechanisms have recently come to light that are important in the hypothalamic control of energy balance, which could play a role in perpetuating the effect of a high-fat diet on hypothalamic dysfunction. These include: reactive oxygen species as an important second messenger, lipid metabolism, autophagy and neuronal and synaptic plasticity. The importance of nutritional activation of the Toll-like receptor 4 and the inhibitor of NF-?B kinase subunit ?/NK-?B and c-Jun amino-terminal kinase 1 inflammatory pathways in linking a high-fat diet to obesity and insulin insensitivity via the hypothalamus is now widely recognised. All of the hypothalamic changes induced by a high-fat diet appear to be causally linked and inhibitors of inflammation, ER stress and autophagy defect can prevent or reverse the development of obesity pointing to potential drug targets in the prevention of obesity and metabolic dysfunction.

PMID: 22954151 [PubMed - as supplied by publisher]

gpcr pathway NF-κB NF-kB signaling pathway

Probing the binding site of the A1 adenosine receptor reengineered for orthogonal recognition by tailored nucleosides.

Probing the binding site of the A1 adenosine receptor reengineered for orthogonal recognition by tailored nucleosides.

Biochemistry. 2007 Jun 26;46(25):7437-48

Authors: Palaniappan KK, Gao ZG, Ivanov AA, Greaves R, Adachi H, Besada P, Kim HO, Kim AY, Choe SA, Jeong LS, Jacobson KA

Abstract
His272 (7.43) in the seventh transmembrane domain (TM7) of the human A3 adenosine receptor (AR) interacts with the 3' position of nucleosides, based on selective affinity enhancement at a H272E mutant A3 AR (neoceptor) of 3'-ureido, but not 3'-OH, adenosine analogues. Here, mutation of the analogous H278 of the human A1 AR to Ala, Asp, Glu, or Leu enhanced the affinity of novel 2'- and 3'-ureido adenosine analogues, such as 10 (N6-cyclopentyl-3'-ureido-3'-deoxyadenosine), by >100-fold, while decreasing the affinity or potency of adenosine and other 3'-OH adenosine analogues. His278 mutant receptors produced a similar enhancement regardless of the charge character of the substituted residue, implicating steric rather than electrostatic factors in the gain of function, a hypothesis supported by rhodopsin-based molecular modeling. It was also demonstrated that this interaction was orientationally specific; i.e., mutations at the neighboring Thr277 did not enhance the affinity for a series of 2'- and 3'-ureido nucleosides. Additionally, H-bonding groups placed on substituents at the N6 or 5' position demonstrated no enhancement in the mutant receptors. These reengineered human A1 ARs revealed orthogonality similar to that of the A3 but not the A2A AR, in which mutation of the corresponding residue, His278, to Asp did not enhance nucleoside affinity. Functionally, the H278D A1 AR was detectable only in a measure of membrane potential and not in calcium mobilization. This neoceptor approach should be useful for the validation of molecular modeling and the dissection of promiscuous GPCR signaling.

PMID: 17542617 [PubMed - indexed for MEDLINE]

G-protein Receptors gpcr pathway NF-κB

Latest development in drug discovery on G protein-coupled receptors.

Latest development in drug discovery on G protein-coupled receptors.

Curr Protein Pept Sci. 2006 Oct;7(5):465-70

Authors: Lundstrom K

Abstract
G protein-coupled receptors (GPCRs) represent the family of proteins with the highest impact from social, therapeutic and economic point of view. Today, more than 50% of drug targets are based on GPCRs and the annual worldwide sales exceeds 50 billion dollars. GPCRs are involved in all major disease areas such as cardiovascular, metabolic, neurodegenerative, psychiatric, cancer and infectious diseases. The classical drug discovery process has relied on screening compounds, which interact favorably with the GPCR of interest followed by further chemical engineering as a mean of improving efficacy and selectivity. In this review, methods for sophisticated chemical library screening procedures will be presented. Furthermore, development of cell-based assays for functional coupling of GPCRs to G proteins will be discussed. Finally, the possibility of applying structure-based drug design will be summarized. This includes the application of bioinformatics knowledge and molecular modeling approaches in drug development programs. The major efforts established through large networks of structural genomics on GPCRs, where recombinantly expressed GPCRs are subjected to purification and crystallization attempts with the intention of obtaining high-resolution structures, are presented as a promising future approach for tailor-made drug development.

PMID: 17073697 [PubMed - indexed for MEDLINE]

NF-kappaB signaling pathway NF-kB signaling pathway NF-kB pathway

2012年9月7日星期五

Trichoderma G protein-coupled receptors: functional characterisation of a cAMP receptor-like protein from Trichoderma atroviride.

Trichoderma G protein-coupled receptors: functional characterisation of a cAMP receptor-like protein from Trichoderma atroviride.

Curr Genet. 2008 Dec;54(6):283-99

Authors: Brunner K, Omann M, Pucher ME, Delic M, Lehner SM, Domnanich P, Kratochwill K, Druzhinina I, Denk D, Zeilinger S

Abstract
Galpha subunits act to regulate vegetative growth, conidiation, and the mycoparasitic response in Trichoderma atroviride. To extend our knowledge on G protein signalling, we analysed G protein-coupled receptors (GPCRs). As the genome sequence of T. atroviride is not publicly available yet, we carried out an in silico exploration of the genome database of the close relative T. reesei. Twenty genes encoding putative GPCRs distributed over eight classes and additional 35 proteins similar to the Magnaporthe grisea PTH11 receptor were identified. Subsequently, four T. atroviride GPCR-encoding genes were isolated and affiliated to the cAMP receptor-like family by phylogenetic and topological analyses. All four genes showed lowest expression on glycerol and highest mRNA levels upon carbon starvation. Transcription of gpr3 and gpr4 responded to exogenously added cAMP and the shift from liquid to solid media. gpr3 mRNA levels also responded to the presence of fungal hyphae or cellulose membranes. Further characterisation of mutants bearing a gpr1-silencing construct revealed that Gpr1 is essential for vegetative growth, conidiation and conidial germination. Four genes encoding the first GPCRs described in Trichoderma were isolated and their expression characterized. At least one of these GPCRs is important for several cellular processes, supporting the fundamental role of G protein signalling in this fungus.

PMID: 18836726 [PubMed - indexed for MEDLINE]

gpcr pathway NF-κB NF-kB signaling pathway

Increased nuclear factor-?B and loss of p53 are key mechanisms in Myalgic Encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Increased nuclear factor-?B and loss of p53 are key mechanisms in Myalgic Encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Med Hypotheses. 2012 Aug 27;

Authors: Morris G, Maes M

Abstract
Fukuda's criteria are adequate to make a distinction between Myalgic Encephalomyelitis/chronic fatigue syndrome (ME/CFS) and chronic fatigue (CF), but ME/CFS patients should be subdivided into those with (termed ME) and without (termed CFS) post exertional malaise [Maes et al. 2012]. ME/CFS is considered to be a neuro-immune disease. ME/CFS is characterized by activated immuno-inflammatory pathways, including increased levels of pro-inflammatory cytokines, nuclear factor ?B (NF-?B) and aberrations in mitochondrial functions, including lowered ATP. These processes may explain typical symptoms of ME/CFS, e.g. fatigue, malaise, hyperalgesia, and neurologic and autonomic symptoms. Here we hypothesize that increased NF-?B together with a loss of p53 are key phenomena in ME/CFS that further explain ME/CFS symptoms, such as fatigue and neurocognitive dysfunction, and explain ME symptoms, such as post-exertional malaise following mental and physical activities. Inactivation of p53 impairs aerobic mitochondrial functions and causes greater dependence on anaerobic glycolysis, elevates lactate levels, reduces mitochondrial density in skeletal muscle and reduces endurance during physical exercise. Lowered p53 and increased NF-?B are associated with elevated reactive oxygen species. Increased NF-?B induces the production of pro-inflammatory cytokines, which increase glycolysis and further compromise mitochondrial functions. All these factors together may contribute to mitochondrial exhaustion and indicate that the demand for extra ATP upon the commencement of increased activity cannot be met. In conditions of chronic inflammation and oxidative stress, high NF-?B and low p53 may conspire to promote neuron and glial cell survival at a price of severely compromised metabolic brain function. Future research should examine p53 signaling in ME/CFS.

PMID: 22951418 [PubMed - as supplied by publisher]

look at here discover more info here find out more info

Pentoxifylline decreases soluble CD40 ligand concentration and CD40 gene expression in coronary artery disease patients.

Pentoxifylline decreases soluble CD40 ligand concentration and CD40 gene expression in coronary artery disease patients.

Immunopharmacol Immunotoxicol. 2012 Jun;34(3):523-9

Authors: Shamsara J, Mohammadpour AH, Behravan J, Falsoleiman H, Ramezani M

Abstract
CONTEXT AND OBJECTIVE: Increased level of inflammatory mediators plays a central role in the features of coronary artery diseases (CAD). As pentoxifylline could suppress the inflammatory process and has shown some promising beneficial effects in inflammatory diseases, we evaluated the effect of 2 months pentoxifylline administration in patients with CAD.
MATERIALS AND METHODS: A randomized placebo-controlled double-blind study design was used. Forty CAD patients (32 males and 8 females) were randomized into either 2 months of pentoxifylline treatment (1200?mg/day) (n?=?20) or placebo treatment (n?=?20). Blood samples were obtained before and after treatment. Gene expression analysis for mRNA of CD40, p65 and I?B? in peripheral blood mononuclear cells (PBMCs) were performed using real-time reverse-transcription polymerase chain reaction (RT-PCR). Plasma concentration of soluble CD40 (sCD40) ligand as well as protein concentration of p50 were measured by ELISA method.
RESULTS: Pentoxifylline decreased CD40 mRNA by 45% (p?<?0.05) in PBMCs and sCD40 ligand level in plasma of CAD patients by 34% (p?<?0.01).
DISCUSSION AND CONCLUSION: Pentoxifylline treatment can suppress the CD40/CD40 ligand system activation in CAD patients. As this system has a role in plaque progression and plaque rupture, pentoxifylline could be a good choice for future studies in preventing cardiovascular events.

PMID: 21999662 [PubMed - indexed for MEDLINE]

Chemokine receptor CCR2 undergoes transportin1-dependent nuclear translocation.

Chemokine receptor CCR2 undergoes transportin1-dependent nuclear translocation.

Proteomics. 2008 Nov;8(21):4560-76

Authors: Favre N, Camps M, Arod C, Chabert C, Rommel C, Pasquali C

Abstract
Chemokines (CCs) are small chemoattractant cytokines involved in a wide variety of biological and pathological processes. Released by cells in the milieu, and extracellular matrix and activating signalling cascades upon binding to specific G protein-coupled receptors (GPCRs), they trigger many cellular events. In various pathologies, CCs are directly responsible for excessive recruitment of leukocytes to inflammatory sites and recent studies using chemokine receptor (CCR) antagonists permitted these molecules to reach the market for medical use. While interaction of CCs with their receptors has been extensively documented, downstream GPCR signalling cascades triggered by CC are less well understood. Given the pivotal role of chemokine receptor 2 (CCR2) in monocyte recruitment, activation and differentiation and its implication in several autoimmune-inflammatory pathologies, we searched for potential new CCR2-interacting proteins by engineering a modified CCR2 that we used as bait. Herein, we show the direct interaction of CCR2 with transportin1 (TRN1), which we demonstrate is followed by CCR2 receptor internalization. Further characterization of this novel interaction revealed that TRN1-binding to CCR2 increased upon time in agonist treated cells and promotes its nuclear translocation in a TRN1-dependent manner. Finally, we provide evidence that following translocation, the receptor localizes at the outer edge of the nuclear envelope where it is finally released from TRN1.

PMID: 18846510 [PubMed - indexed for MEDLINE]

learn more see here look at here

Evolutionary Analysis of Functional Divergence among Chemokine Receptors, Decoy Receptors, and Viral Receptors.

Evolutionary Analysis of Functional Divergence among Chemokine Receptors, Decoy Receptors, and Viral Receptors.

Front Microbiol. 2012;3:264

Authors: Daiyasu H, Nemoto W, Toh H

Abstract
Chemokine receptors (CKRs) function in the inflammatory response and in vertebrate homeostasis. Decoy and viral receptors are two types of CKR homologs with modified functions from those of the typical CKRs. The decoy receptors are able to bind ligands without signaling. On the other hand, the viral receptors show constitutive signaling without ligands. We examined the sites related to the functional difference. At first, the decoy and viral receptors were each classified into five groups, based on the molecular phylogenetic analysis. A multiple amino acid sequence alignment between each group and the CKRs was then constructed. The difference in the amino acid composition between the group and the CKRs was evaluated as the Kullback-Leibler (KL) information value at each alignment site. The KL information value is considered to reflect the difference in the functional constraints at the site. The sites with the top 5% of KL information values were selected and mapped on the structure of a CKR. The comparisons with decoy receptor groups revealed that the detected sites were biased on the intracellular side. In contrast, the sites detected from the comparisons with viral receptor groups were found on both the extracellular and intracellular sides. More sites were found in the ligand binding pocket in the analyses of the viral receptor groups, as compared to the decoy receptor groups. Some of the detected sites were located in the GPCR motifs. For example, the DRY motif of the decoy receptors was often degraded, although the motif of the viral receptors was basically conserved. The observations for the viral receptor groups suggested that the constraints in the pocket region are loose and that the sites on the intracellular side are different from those for the decoy receptors, which may be related to the constitutive signaling activity of the viral receptors.

PMID: 22855685 [PubMed - in process]

NF-kappaB signaling pathway NF-kB signaling pathway NF-kB pathway

2012年9月6日星期四

Classification of G-protein coupled receptors at four levels.

Classification of G-protein coupled receptors at four levels.

Protein Eng Des Sel. 2006 Nov;19(11):511-6

Authors: Gao QB, Wang ZZ

Abstract
G-protein coupled receptors (GPCRs) are transmembrane proteins which via G-proteins initiate some of the important signaling pathways in a cell and are involved in various physiological processes. Thus, computational prediction and classification of GPCRs can supply significant information for the development of novel drugs in pharmaceutical industry. In this paper, a nearest neighbor method has been introduced to discriminate GPCRs from non-GPCRs and subsequently classify GPCRs at four levels on the basis of amino acid composition and dipeptide composition of proteins. Its performance is evaluated on a non-redundant dataset consisted of 1406 GPCRs for six families and 1406 globular proteins using the jackknife test. The present method based on amino acid composition achieved an overall accuracy of 96.4% and Matthew's correlation coefficient (MCC) of 0.930 for correctly picking out the GPCRs from globular proteins. The overall accuracy and MCC were further enhanced to 99.8% and 0.996 by dipeptide composition-based method. On the other hand, the present method has successfully classified 1406 GPCRs into six families with an overall accuracy of 89.6 and 98.8% using amino acid composition and dipeptide composition, respectively. For the subfamily prediction of 1181 GPCRs of rhodopsin-like family, the present method achieved an overall accuracy of 76.7 and 94.5% based on the amino acid composition and dipeptide composition, respectively. Finally, GPCRs belonging to the amine subfamily and olfactory subfamily of rhodopsin-like family were further analyzed at the type level. The overall accuracy of dipeptide composition-based method for the classification of amine type and olfactory type of GPCRs reached 94.5 and 86.9%, respectively, while the overall accuracy of amino acid composition-based method was very low for both subfamilies. In comparison with existing methods in the literature, the present method also displayed great competitiveness. These results demonstrate the effectiveness of our method on identifying and classifying GPCRs correctly. GPCRsIdentifier, a corresponding stand-alone executable program for GPCR identification and classification was also developed, which can be acquired freely on request from the authors for academic purposes.

PMID: 17032692 [PubMed - indexed for MEDLINE]

NF-kB signaling pathway NF-kB pathway NF-kB signaling

G protein-coupled receptors and their signaling pathways: classical therapeutical targets susceptible to novel therapeutic concepts.

G protein-coupled receptors and their signaling pathways: classical therapeutical targets susceptible to novel therapeutic concepts.

Curr Pharm Des. 2004;10(16):1937-58

Authors: Liebmann C

Abstract
In recent years, new strategies in cancer therapy have been developed targeting key signaling molecules in the receptor tyrosine kinase signal transduction pathway. In contrast, most therapeutical concepts to manipulate G protein-coupled receptors (GPCR)-mediated disorders are still limited to the use of receptor-specific agonists or antagonists. Visible progress in the understanding of GPCR signaling complexity, especially the detection of several families of highly target- and cell-specific regulator proteins of GPCRs, G proteins, and effector components may open new horizons to develop novel therapeutical concepts targeting GPCR signaling elements. Thus, this review will focus on different molecular levels that may be of particular interest in terms of new drug development such as: (i) GPCR subtypes, allosteric binding sites, dimerization and constitutive activity, the use of RAMPs (receptor-activity-modifying proteins) and RASSLs (receptor activated solely by synthetic ligands); (ii) AGS (activators of G protein signaling) and RGS (regulators of G protein signaling) proteins which modify G protein activity; (iii) the high diversity of isozymes involved in the generation, signal transmission, and degradation of second messenger molecules.

PMID: 15180530 [PubMed - indexed for MEDLINE]

find out more info GPCR Signaling G-protein Receptors

Rice heterotrimeric G-protein Gamma subunits (RGG1 and RGG2) are differentially regulated under abiotic stress.

Rice heterotrimeric G-protein Gamma subunits (RGG1 and RGG2) are differentially regulated under abiotic stress.

Plant Signal Behav. 2012 Jul 1;7(7)

Authors: Yadav DK, Islam SM, Tuteja N

Abstract
Heterotrimeric G-proteins (?, ? and ? subunits) are primarily involved in diverse signaling processes by transducing signals from an activated transmembrane G-protein coupled receptor (GPCR) to appropriate downstream effectors within cells. The role of ? and ? G-protein subunits in salinity and heat stress has been reported but the regulation of ? subunit of plant G-proteins in response to abiotic stress has not heretofore been described. In the present study we report the isolation of full-length cDNAs of two isoforms of G? [RGG1(I), 282 bp and RGG2(I), 453 bp] from rice (Oryza sativa cv Indica group Swarna) and described their transcript regulation in response to abiotic stresses. Protein sequence alignment and pairwise comparison of ? subunits of Indica rice [RGG(I)] with other known plant G-protein ? subunits demonstrated high homology to barley (HvGs) while soybean (GmG2) and Arabidopsis (AGG1) were least related. The numbers of the exons and introns were found to be similar between RGG1(I) and RGG2(I), but their sizes were different. Analyses of promoter sequences of RGG(I) confirmed the presence of stress-related cis-regulatory signature motifs suggesting their active and possible independent roles in abiotic stress signaling. The transcript levels of RGG1(I) and RGG2(I) were upregulated following NaCl, cold, heat and ABA treatments. However, in drought stress only RGG1(I) was upregulated. Strong support by transcript profiling suggests that ? subunits play a critical role via cross talk in signaling pathways. These findings provide first direct evidence for roles of G? subunits of rice G-proteins in regulation of abiotic stresses. These findings suggest the possible exploitation of ? subunits of G-protein machinery for promoting stress tolerance in plants.

PMID: 22751322 [PubMed - as supplied by publisher]

see here look at here discover more info here

TGF-?-activated kinase 1 promotes cell cycle arrest and cell survival of X-ray irradiated HeLa cells dependent on p21 induction but independent of NF-?B, p38 MAPK and ERK phosphorylations.

TGF-?-activated kinase 1 promotes cell cycle arrest and cell survival of X-ray irradiated HeLa cells dependent on p21 induction but independent of NF-?B, p38 MAPK and ERK phosphorylations.

Radiat Res. 2012 Jun;177(6):766-74

Authors: Furusawa Y, Wei ZL, Sakurai H, Tabuchi Y, Li P, Zhao QL, Nomura T, Saiki I, Kondo T

Abstract
Transforming growth factor-?-activated kinase 1 (TAK1) appears to play a role in inhibiting apoptotic death in response to multiple stresses. To assess the role of TAK1 in X-ray induced apoptosis and cell death, we irradiated parental and siRNA-TAK1-knockdown HeLa cells. Changes in gene expression levels with and without TAK1-knockdown were also examined after irradiation to elucidate the molecular mechanisms involved. After X-ray irradiation, cell death estimated by the colony formation assay increased in the TAK1-knockdown cells. Apoptosis induction, determined by caspase-3 cleavage, suggested that the increased radiosensitivity of the TAK1-knockdown cells could be partially explained by the induction of apoptosis. However, cell cycle analysis revealed that the percentage of irradiated cells in the G(2)/M-phase decreased, and those in the S- and SubG(1)-phases increased due to TAK1 depletion, suggesting that the loss of cell cycle checkpoint regulation may also be involved in the observed increased radiosensitivity. Interestingly, significant differences in the induction of NF-?B, p38 MAPK and ERK phosphorylation, the major downstream molecules of TAK1, were not observed in TAK1 knockdown cells compared to their parental control cells after irradiation. Instead, global gene expression analysis revealed differentially expressed genes after irradiation that bioinformatics analysis suggested are associated with cell cycle regulatory networks. In particular, CDKN1A (coding p21(WAF1)), which plays a central role in the identified network, was up-regulated in control cells but not in TAK1 knockdown cells after X-ray irradiation. Si-RNA knockdown of p21 decreased the percentage of cells in the G(2)/M phase and increased the percentage of cells in the S- and SubG(1)-phases after X-ray irradiation in a similar manner as TAK-1 knockdown. Taken together, these findings suggest that the role of TAK1 in cell death, cell cycle regulation and apoptosis after X irradiation is independent of NF-?B, p38 MAPK, and ERK phosphorylation, and dependent, in part, on p21 induction.

PMID: 22490020 [PubMed - indexed for MEDLINE]

look at here discover more info here find out more info

Glucagon-like peptide-1 synthetic analogs: new therapeutic agents for use in the treatment of diabetes mellitus.

Glucagon-like peptide-1 synthetic analogs: new therapeutic agents for use in the treatment of diabetes mellitus.

Curr Med Chem. 2003 Nov;10(22):2471-83

Authors: Holz GG, Chepurny OG

Abstract
Glucagon-like peptide-1-(7-36)-amide (GLP-1) is a potent blood glucose-lowering hormone now under investigation for use as a therapeutic agent in the treatment of type 2 (adult onset) diabetes mellitus. GLP-1 binds with high affinity to G protein-coupled receptors (GPCRs) located on pancreatic beta-cells, and it exerts insulinotropic actions that include the stimulation of insulin gene transcription, insulin biosynthesis, and insulin secretion. The beneficial therapeutic action of GLP-1 also includes its ability to act as a growth factor, stimulating formation of new pancreatic islets (neogenesis) while slowing beta-cell death (apoptosis). GLP-1 belongs to a large family of structurally-related hormones and neuropeptides that include glucagon, secretin, GIP, PACAP, and VIP. Biosynthesis of GLP-1 occurs in the enteroendocrine L-cells of the distal intestine, and the release of GLP-1 into the systemic circulation accompanies ingestion of a meal. Although GLP-1 is inactivated rapidly by dipeptidyl peptidase IV (DDP-IV), synthetic analogs of GLP-1 exist, and efforts have been directed at engineering these peptides so that they are resistant to enzymatic hydrolysis. Additional modifications of GLP-1 incorporate fatty acylation and drug affinity complex (DAC) technology to improve serum albumin binding, thereby slowing renal clearance of the peptides. NN2211, LY315902, LY307161, and CJC-1131 are GLP-1 synthetic analogs that reproduce many of the biological actions of GLP-1, but with a prolonged duration of action. AC2993 (Exendin-4) is a naturally occurring peptide isolated from the lizard Heloderma, and it acts as a high affinity agonist at the GLP-1 receptor. This review summarizes structural features and signal transduction properties of GLP-1 and its cognate beta-cell GPCR. The usefulness of synthetic GLP-1 analogs as blood glucose-lowering agents is discussed, and the applicability of GLP-1 as a therapeutic agent for treatment of type 2 diabetes is highlighted.

PMID: 14529486 [PubMed - indexed for MEDLINE]

NF-kB signaling NF-kappaB signaling pathway NF-kB signaling pathway

2012年9月5日星期三

Comparison of the effect of p65 siRNA and curcumin in promoting apoptosis in esophageal squamous cell carcinoma cells and in nude mice.

Comparison of the effect of p65 siRNA and curcumin in promoting apoptosis in esophageal squamous cell carcinoma cells and in nude mice.

Oncol Rep. 2012 Jul;28(1):232-40

Authors: Tian F, Zhang C, Tian W, Jiang Y, Zhang X

Abstract
The activation of the NF-?B signaling pathway plays a critical role in carcinogenesis. The role of the NF-?B pathway in esophageal squamous cell carcinoma (ESCC) remains ill-defined. The objective was to detect whether p65siRNA and curcumin could promote ESCC cell apoptosis and increase the sensitivity of ESCC cells to chemotherapeutic drugs by inhibiting the NF-?B signaling pathway, and to compared these two treatments. In the present study, the status of the NF-?B pathway, in the two ESCC cell lines Eca109 and EC9706, was analyzed and the ability of p65 siRNA and curcumin alone or in combination with 5-FU to modulate this pathway in vitro and in vivo was investigated. The results showed that the NF-?B signaling pathway in the ESCC cell lines was constitutively activated. Both p65 siRNA and curcumin mediated suppression of activation of the NF-?B signaling pathway via inhibition of the expression of p65 or I?B? phosphorylation in ESCC cell lines. The cells treated with combination of p65 siRNA or curcumin and 5-FU revealed a lower cell viability and higher apoptosis compared to those treated with 5-FU alone. In a human ESCC xenograft model, p65 siRNA or curcumin and 5-FU alone reduced the tumor volume, respectively, but their combination had the strongest anticancer effects. Curcumin was more effective than p65 siRNA in vitro and in vivo. Overall, our results indicate that the constitutively activated NF-?B signaling pathway plays a crucial role in these two ESCC cell lines and both p65siRNA and curcumin can promote ESCC cell apoptosis and enhance the sensitivity to 5-FU through suppression of the NF-?B signaling pathway. It is still a long time before RNA interference will be used in the clinic. Therefore, curcumin is proved to be useful in the treatment of ESCC as it is a pharmacologically safe compound without side effects.

PMID: 22552693 [PubMed - indexed for MEDLINE]

discover more info here find out more info GPCR Signaling

Inflammation and Barrett's carcinogenesis.

Inflammation and Barrett's carcinogenesis.

Pathol Res Pract. 2012 May 15;208(5):269-80

Authors: Poehlmann A, Kuester D, Malfertheiner P, Guenther T, Roessner A

Abstract
Barrett's esophagus (BE) is one of the most common premalignant lesions in which normal squamous epithelium of the esophagus is replaced by metaplastic columnar epithelium. Esophageal adenocarcinoma (EA) develops through progression from BE to low- and high-grade dysplasia (LGD/HGD) and to adenocarcinoma. It is widely accepted that inflammation can increase cancer risk, promoting tumor progression. Therefore, inflammation is regarded as the seventh hallmark of cancer. In recent years, the inflammation-cancer connection of Barrett's carcinogenesis has been intensively studied, unraveling genetic abnormalities. Besides genetic alterations, inflammation is also epigenetically linked to loss of protein expression through transcriptional silencing via promoter methylation. Key mediators linking inflammation and Barrett's carcinogenesis include reactive oxygen species (ROS), NF?B, inflammatory cytokines, prostaglandins, and specific microRNAs (miRNAs). Therefore, the decipherment of molecular pathways that contain these and novel inflammatory key mediators is of major importance for diagnosis, therapy, and prognosis. The detailed elucidation of the signaling molecules involved in Barrett's carcinogenesis will be important for the development of pharmaceutical inhibitors. We herein give an overview of the current knowledge of the inflammation-mediated genetic and epigenetic alterations involved in Barrett's carcinogenesis. We highlight the role of oxidative stress and deregulated DNA damage checkpoints besides the NF?B pathway.

PMID: 22541897 [PubMed - indexed for MEDLINE]

NF-kB pathway NF-kB signaling NF-kappaB signaling pathway

Selection and characterization of DARPins specific for the neurotensin receptor 1.

Selection and characterization of DARPins specific for the neurotensin receptor 1.

Protein Eng Des Sel. 2009 Jun;22(6):357-66

Authors: Milovnik P, Ferrari D, Sarkar CA, Pl�ckthun A

Abstract
We describe here the selection and characterization of designed ankyrin repeat proteins (DARPins) that bind specifically to the rat neurotensin receptor 1 (NTR1), a G-protein coupled receptor (GPCR). The selection procedure using ribosome display and the initial clone analysis required <10 microg of detergent-solubilized, purified NTR1. Complex formation with solubilized GPCR was demonstrated by ELISA and size-exclusion chromatography; additionally, the GPCR could be detected in native membranes of mammalian cells using fluorescence microscopy. The main binding epitope in the GPCR lies within the 33 amino acids following the seventh transmembrane segment, which comprise the putative helix 8, and additional binding interactions are possibly contributed by the cytoplasmic loop 3, thus constituting a discontinuous epitope. Since the selected binders recognize the GPCR both in detergent-solubilized and in membrane-embedded forms, they will be potentially useful both in co-crystallization trials and for signal transduction experiments.

PMID: 19389717 [PubMed - indexed for MEDLINE]

2012年9月4日星期二

Exploiting synthetic lethality for the therapy of ABC diffuse large B cell lymphoma.

Exploiting synthetic lethality for the therapy of ABC diffuse large B cell lymphoma.

Cancer Cell. 2012 Jun 12;21(6):723-37

Authors: Yang Y, Shaffer AL, Emre NC, Ceribelli M, Zhang M, Wright G, Xiao W, Powell J, Platig J, Kohlhammer H, Young RM, Zhao H, Yang Y, Xu W, Buggy JJ, Balasubramanian S, Mathews LA, Shinn P, Guha R, Ferrer M, Thomas C, Waldmann TA, Staudt LM

Abstract
Knowledge of oncogenic mutations can inspire therapeutic strategies that are synthetically lethal, affecting cancer cells while sparing normal cells. Lenalidomide is an active agent in the activated B cell-like (ABC) subtype of diffuse large B cell lymphoma (DLBCL), but its mechanism of action is unknown. Lenalidomide kills ABC DLBCL cells by augmenting interferon ? (IFN?) production, owing to the oncogenic MYD88 mutations in these lymphomas. In a cereblon-dependent fashion, lenalidomide downregulates IRF4 and SPIB, transcription factors that together prevent IFN? production by repressing IRF7 and amplify prosurvival NF-?B signaling by transactivating CARD11. Blockade of B cell receptor signaling using the BTK inhibitor ibrutinib also downregulates IRF4 and consequently synergizes with lenalidomide in killing ABC DLBCLs, suggesting attractive therapeutic strategies.

PMID: 22698399 [PubMed - indexed for MEDLINE]

NF-kB signaling pathway

Engineering the melanocortin-4 receptor to control G(s) signaling in vivo.

Engineering the melanocortin-4 receptor to control G(s) signaling in vivo.

Ann N Y Acad Sci. 2003 Jun;994:225-32

Authors: Srinivasan S, Vaisse C, Conklin BR

Abstract
G-protein-coupled receptors (GPCRs) are the largest known family of cell surface receptors, and they control many important physiological events, including sensory perception, chemotaxis, neurotransmission, and energy homeostasis. However, GPCR signaling can be difficult to study in vivo because of the multitude of GPCRs, the lack of specific synthetic agonists, and the fact that some GPCRs activate multiple signaling pathways. One method to circumvent these problems is to develop an engineered receptor that is unresponsive to its endogenous agonist, yet can be fully activated by synthetic, small-molecule drugs. Such a receptor, called a receptor activated solely by a synthetic ligand (RASSL), can be rapidly and reversibly activated by a small-molecule drug and would be a powerful tool to control G-protein signaling in vivo. Here we present the development of a G(s)-coupled RASSL based on the melanocortin-4 receptor (MC4R). MC4R couples exclusively to G(s) at physiologically relevant concentrations of its endogenous ligand, alpha-melanocyte-stimulating hormone (alpha-MSH). Data from human patients and structure-activity studies have shown that several mutations in MC4R cause a decreased affinity for alpha-MSH and can be exploited for RASSL development. Synthetic, small-molecule agonists of MC4R are now available and can be used to activate mutated receptors in vivo. We are engineering a series of mutations in MC4R to remove the peptide-binding site while retaining small-molecule binding and activation. The MC4R G(s) RASSL could be used to control many physiological responses associated with G(s) signaling such as heart rate, energy homeostasis, and cell proliferation.

PMID: 12851320 [PubMed - indexed for MEDLINE]

learn more see here look at here

Rice heterotrimeric G-protein Gamma subunits (RGG1 and RGG2) are differentially regulated under abiotic stress.

Rice heterotrimeric G-protein Gamma subunits (RGG1 and RGG2) are differentially regulated under abiotic stress.

Plant Signal Behav. 2012 Jul 1;7(7)

Authors: Yadav DK, Islam SM, Tuteja N

PMID: 22751322 [PubMed - as supplied by publisher]

NF-kB pathway NF-kB signaling NF-kappaB signaling pathway

Directed molecular evolution of DREADDs: a generic approach to creating next-generation RASSLs.

Directed molecular evolution of DREADDs: a generic approach to creating next-generation RASSLs.

Nat Protoc. 2010 Mar;5(3):561-73

Authors: Dong S, Rogan SC, Roth BL

Abstract
G protein-coupled receptors (GPCRs) and their downstream signaling cascades contribute to most physiological processes and a variety of human diseases. Isolating the effects of GPCR activation in an in vivo experimental setting is challenging as exogenous ligands have off-target effects and endogenous ligands constantly modulate the activity of native receptors. Highly specific designer drug-designer receptor complexes are a valuable tool for elucidating the effects of activating particular receptors and signaling pathways within selected cell types in vivo. In this study, we describe a generic protocol for the directed molecular evolution of designer receptors exclusively activated by designer drugs (DREADDs). First, the yeast system is validated with the template receptor. Second, a mutant library is generated by error-prone PCR. Third, the library is screened by drug-dependent yeast growth assays. Mutants exhibiting the desired properties are selected for further rounds of mutagenesis or for characterization in mammalian systems. In total, these steps should take 6-8 weeks of experimentation and should result in the evolution of a receptor to be activated by the chosen ligand. This protocol should help improve the experimental targeting of select cell populations.

PMID: 20203671 [PubMed - indexed for MEDLINE]

see here look at here discover more info here

An algebra of dimerization and its implications for G-protein coupled receptor signaling.

An algebra of dimerization and its implications for G-protein coupled receptor signaling.

J Theor Biol. 2004 Jul 21;229(2):157-68

Authors: Woolf PJ, Linderman JJ

Abstract
Many species of receptors form dimers, but how can we use this information to make predictions about signal transduction? This problem is particularly difficult when receptors dimerize with many different species, leading to a combinatoric increase in the possible number of dimer pairs. As an example system, we focus on receptors in the G-protein coupled receptor (GPCR) family. GPCRs have been shown to reversibly form dimers, but this dimerization does not directly affect signal transduction. Here we present a new theoretical framework called a dimerization algebra. This algebra provides a systematic and rational way to represent, manipulate, and in some cases simplify large and often complicated networks of dimerization interactions. To compliment this algebra, Monte Carlo simulations are used to predict dimerization's effect on receptor organization on the membrane, signal transduction, and internalization. These simulation results are directly comparable to various experimental measures such as fluorescence resonance energy transfer (FRET), and as such provide a link between the dimerization algebra and experimental data. As an example, we show how the algebra and computational results can be used to predict the effects of dimerization on the dopamine D2 and somatastatin SSTR1 receptors. When these predictions were compared to experimental findings from the literature, good agreement was found, demonstrating the utility of our approach. Applications of this work to the development of a novel class of dimerization-modulating drugs are also discussed.

PMID: 15207471 [PubMed - indexed for MEDLINE]

NF-kappaB signaling pathway NF-kB signaling pathway NF-kB pathway

2012年9月3日星期一

Subtype-specific roles of phospholipase C-? via differential interactions with PDZ domain proteins.

Subtype-specific roles of phospholipase C-? via differential interactions with PDZ domain proteins.

Adv Enzyme Regul. 2011;51(1):138-51

Authors: Kim JK, Lim S, Kim J, Kim S, Kim JH, Ryu SH, Suh PG

Abstract
Since we first identified the PLC-? isozyme, enormous studies have been conducted to investigate the functional roles of this protein (Min et al., 1993; Suh et al.,1988). It is now well-known that the four PLC-? subtypes are major effector molecules in GPCR-mediated signaling, especially for intracellular Ca2+ signaling. Nonetheless, it is still poorly understood why multiple PLC-? subtype exist. Most cells express multiple subtypes of PLC-? in different combinations, and each subtype is involved in somewhat different signaling pathways. Therefore, studying the differential roles of each PLC-? subtype is a very interesting issue. In this regard, we focus here on PDZ domain proteins which are novel PLC-? interacting proteins. As scaffolders, PDZ domain proteins recruit various target proteins ranging from membrane receptors to cytoskeletal proteins to assemble highly organized signaling complexes; this can give rise to efficiency and diversity in cellular signaling. Because PLC-? subtypes have different PDZ-binding motifs, it is possible that they are engaged with different PDZ domain proteins, and in turn participate in distinct physiological responses. To date, several PDZ domain proteins, such as the NHERF family, Shank2, and Par-3, have been reported to selectively interact with certain PLC-? subtypes and GPCRs. Systematic predictions of potential binding partners also suggests differential binding properties between PLC-? subtypes. Furthermore, we elucidated parallel signaling processes for multiple PLC-? subtypes, which still perform distinct functions resulting from differential interactions with PDZ domain proteins within a single cell. Therefore, these results highlight the novel function of PDZ domain proteins as intermediaries in subtype-specific role of PLC-? in GPCR-mediated signaling. Future studies will focus on the physiological meanings of this signaling complex formation by different PDZ domain proteins and PLC-? subtypes. It has been observed for a long time that the expression of certain PLC-? subtype fluctuates during diverse physiological conditions. For example, the expression of PLC-?1 is selectively increased during myoblast and adipocyte differentiation (Faenza et al., 2004; O'Carroll et al., 2009). Likewise, PLC-?2 is highly up-regulated during breast cancer progression and plays a critical role in cell migration and mitosis (Bertagnolo et al., 2007). Although PLC-?3 is selectively down-regulated in neuroendocrine tumors, the expression of PLC-?1 is increased in small cell lung carcinoma (Stalberg et al., 2003; Strassheim et al., 2000). In our hypothetical model, it is most likely that up- and down regulation of certain PLC-? subtypes are due to their selective coupling with specific GPCR-mediated signaling, implicated in these pathophysiologic conditions. Therefore, better understanding of selective coupling between PLC-? subtypes, PDZ domain proteins, and GPCRs will shed light on new prognosis and therapy of diverse diseases, and provide potential targets for drug development.

PMID: 21035486 [PubMed - indexed for MEDLINE]

find out more info GPCR Signaling G-protein Receptors

Regulation of cytochrome P450 4F11 by nuclear transcription factor-?B.

Regulation of cytochrome P450 4F11 by nuclear transcription factor-?B.

Drug Metab Dispos. 2012 Jan;40(1):205-11

Authors: Bell JC, Strobel HW

Abstract
Although the mechanisms that regulate CYP4F genes have been and are currently being studied in a number of laboratories, the specific mechanisms for the regulation of these genes are not yet fully understood. This study shows that nuclear factor ?B of the light-chain-enhancer in activated B cells (NF-?B) can inhibit CYP4F11 expression in human liver carcinoma cell line (HepG2) as summarized below. Tumor necrosis factor-? (TNF-?), a proinflammatory cytokine, has been shown to activate NF-?B signaling while also activating the c-Jun NH(2)-terminal kinase (JNK) signaling pathway. Other studies have reported that JNK signaling can up-regulate CYP4F11 expression. The results of this study demonstrate that in the presence of TNF-? and the specific NF-?B translocation inhibitor N-[3,5-bis(trifluoromethyl)phenyl]-5-chloro-2-hydroxybenzamide (IMD-0354), there is a greater increase in CYP4F11 expression than that elicited by TNF-? alone, indicating that NF-?B plays an inhibitory role. Moreover, NF-?B stimulation by overexpression of mitogen-activated protein kinase kinase kinase inhibited CYP4F11 promoter expression. CYP4F11 promoter inhibition can also be rescued in the presence of TNF-? when p65, a NF-?B protein, is knocked down. Thus, NF-?B signaling pathways negatively regulate the CYP4F11 gene.

PMID: 22011441 [PubMed - indexed for MEDLINE]

GPCR Signaling G-protein Receptors gpcr pathway

Engineering GPCR signaling pathways with RASSLs.

Engineering GPCR signaling pathways with RASSLs.

Nat Methods. 2008 Aug;5(8):673-8

Authors: Conklin BR, Hsiao EC, Claeysen S, Dumuis A, Srinivasan S, Forsayeth JR, Guettier JM, Chang WC, Pei Y, McCarthy KD, Nissenson RA, Wess J, Bockaert J, Roth BL

Abstract
We are creating families of designer G protein-coupled receptors (GPCRs) to allow for precise spatiotemporal control of GPCR signaling in vivo. These engineered GPCRs, called receptors activated solely by synthetic ligands (RASSLs), are unresponsive to endogenous ligands but can be activated by nanomolar concentrations of pharmacologically inert, drug-like small molecules. Currently, RASSLs exist for the three major GPCR signaling pathways (G(s), G(i) and G(q)). We review these advances here to facilitate the use of these powerful and diverse tools.

PMID: 18668035 [PubMed - indexed for MEDLINE]

NF-kB signaling NF-kappaB signaling pathway NF-kB signaling pathway

G protein-coupled receptors and their signaling pathways: classical therapeutical targets susceptible to novel therapeutic concepts.

G protein-coupled receptors and their signaling pathways: classical therapeutical targets susceptible to novel therapeutic concepts.

Curr Pharm Des. 2004;10(16):1937-58

Authors: Liebmann C

PMID: 15180530 [PubMed - indexed for MEDLINE]

discover more info here find out more info GPCR Signaling

Glucagon-like peptide-1 synthetic analogs: new therapeutic agents for use in the treatment of diabetes mellitus.

Glucagon-like peptide-1 synthetic analogs: new therapeutic agents for use in the treatment of diabetes mellitus.

Curr Med Chem. 2003 Nov;10(22):2471-83

Authors: Holz GG, Chepurny OG

PMID: 14529486 [PubMed - indexed for MEDLINE]

NF-kB pathway NF-kB signaling NF-kappaB signaling pathway

2012年9月2日星期日

Chimeric yeast G-protein ? subunit harboring a 37-residue C-terminal gustducin-specific sequence is functional in Saccharomyces cerevisiae.

Chimeric yeast G-protein ? subunit harboring a 37-residue C-terminal gustducin-specific sequence is functional in Saccharomyces cerevisiae.

Biosci Biotechnol Biochem. 2012;76(3):512-6

Authors: Hara K, Inada Y, Ono T, Kuroda K, Yasuda-Kamatani Y, Ishiguro M, Tanaka T, Misaka T, Abe K, Ueda M

Abstract
Despite many recent studies of G-protein-coupled receptor (GPCR) structures, it is not yet well understood how these receptors activate G proteins. The GPCR assay using baker's yeast, Saccharomyces cerevisiae, is an effective experimental model for the characterization of GPCR-G? interactions. Here, using the yeast endogenous G? protein (Gpa1p) as template, we constructed various chimeric G? proteins with a region that is considered to be necessary for interaction with mammalian receptors. The signaling assay using the yeast pheromone receptor revealed that the chimeric G? protein harboring 37 gustducin-specific amino acid residues at its C-terminus (GPA1/gust37) maintained functionality in yeast. In contrast, GPA1/gust44, a variant routinely used in mammalian experimental systems, was not functional.

PMID: 22451393 [PubMed - indexed for MEDLINE]

discover more info here find out more info GPCR Signaling

Modifying ligand-induced and constitutive signaling of the human 5-HT4 receptor.

Modifying ligand-induced and constitutive signaling of the human 5-HT4 receptor.

PLoS One. 2007;2(12):e1317

Authors: Chang WC, Ng JK, Nguyen T, Pellissier L, Claeysen S, Hsiao EC, Conklin BR

Abstract
G protein-coupled receptors (GPCRs) signal through a limited number of G-protein pathways and play crucial roles in many biological processes. Studies of their in vivo functions have been hampered by the molecular and functional diversity of GPCRs and the paucity of ligands with specific signaling effects. To better compare the effects of activating different G-protein signaling pathways through ligand-induced or constitutive signaling, we developed a new series of RASSLs (receptors activated solely by synthetic ligands) that activate different G-protein signaling pathways. These RASSLs are based on the human 5-HT(4b) receptor, a GPCR with high constitutive G(s) signaling and strong ligand-induced G-protein activation of the G(s) and G(s/q) pathways. The first receptor in this series, 5-HT(4)-D(100)A or Rs1 (RASSL serotonin 1), is not activated by its endogenous agonist, serotonin, but is selectively activated by the small synthetic molecules GR113808, GR125487, and RO110-0235. All agonists potently induced G(s) signaling, but only a few (e.g., zacopride) also induced signaling via the G(q) pathway. Zacopride-induced G(q) signaling was enhanced by replacing the C-terminus of Rs1 with the C-terminus of the human 5-HT(2C) receptor. Additional point mutations (D(66)A and D(66)N) blocked constitutive G(s) signaling and lowered ligand-induced G(q) signaling. Replacing the third intracellular loop of Rs1 with that of human 5-HT(1A) conferred ligand-mediated G(i) signaling. This G(i)-coupled RASSL, Rs1.3, exhibited no measurable signaling to the G(s) or G(q) pathway. These findings show that the signaling repertoire of Rs1 can be expanded and controlled by receptor engineering and drug selection.

PMID: 18338032 [PubMed - indexed for MEDLINE]

NF-kB signaling pathway NF-kB pathway NF-kB signaling

Altered IkappaBalpha expression promotes NF-kappaB activation in monocytes from primary Sj�gren's syndrome patients.

Altered IkappaBalpha expression promotes NF-kappaB activation in monocytes from primary Sj�gren's syndrome patients.

Pathology. 2012 Aug 29;

Authors: Lisi S, Sisto M, Lofrumento DD, D'Amore M

Abstract
AIMS:: To study the importance of I?B? in NF-?B signal transduction, we analysed the I?B? expression in monocytes from Sj�gren's syndrome (SS) patients versus healthy controls. METHODS:: Monocytes were obtained from the peripheral blood of 30 SS patients and 23 healthy subjects. I?B? expression was studied by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), real-time PCR, immunoblotting, flow cytometry and enzyme linked immunosorbent assay (ELISA). RESULTS:: Analysis of the gene and protein expression profiles of SS monocytes revealed a down-regulation of I?B?, and in all the Sj�gren's syndrome cases examined, serum I?B? levels were significantly decreased in comparison with controls. CONCLUSIONS:: Our findings clearly demonstrate changes in the levels of I?B? in SS monocytes, suggesting that the attenuated expression of I?B? could contribute to the deregulation of NF-?B pathways in the SS pathogenesis. Decreased expression of I?B? may specifically amplify cytokines production and inflammatory response linked to Sj�gren's syndrome.

PMID: 22935973 [PubMed - as supplied by publisher]

NF-kB pathway NF-kB signaling NF-kappaB signaling pathway

Subtype-specific roles of phospholipase C-? via differential interactions with PDZ domain proteins.

Subtype-specific roles of phospholipase C-? via differential interactions with PDZ domain proteins.

Adv Enzyme Regul. 2011;51(1):138-51

Authors: Kim JK, Lim S, Kim J, Kim S, Kim JH, Ryu SH, Suh PG

PMID: 21035486 [PubMed - indexed for MEDLINE]

NF-kB signaling NF-kappaB signaling pathway NF-kB signaling pathway

订阅：博文 (Atom)