Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.5.1.18 (glutathione S-transferase)
22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polycystin-2 (PC2) is the product of the PKD2 gene, which is mutated in 10-15% patients of autosomal dominant polycystic kidney disease (ADPKD). PC2 is an integral transmembrane protein and acts as a calcium-permeable cation channel. The functional modulation of this channel by other protein partners remains largely unknown. In the present study, using a yeast two-hybrid approach, we discovered that both intracellular N- and C-termini of PC2 associate with alpha-actinins, actin-binding and actin-bundling proteins important in cytoskeleton organization, cell adhesion, proliferation and migration. The PC2-alpha-actinin association was confirmed by in vitro glutathione S-transferase pull-down and dot blot overlay assays. In addition, the in vivo interaction between endogenous PC2 and alpha-actinins was demonstrated by co-immunoprecipitation in human embryonic kidney 293 and Madin-Darby canine kidney (MDCK) cells, rat kidney and heart tissues and human syncytiotrophoblast (hST) apical membrane vesicles. Immunofluorescence experiments showed that PC2 and alpha-actinin were partially co-localized in epithelial MDCK and inner medullary collecting duct cells, NIH 3T3 fibroblasts and hST vesicles. We studied the functional modulation of PC2 by alpha-actinin in a lipid bilayer electrophysiology system using in vitro translated PC2 and found that alpha-actinin substantially stimulated the channel activity of reconstituted PC2. A similar stimulatory effect of alpha-actinin on PC2 was also observed when hST vesicles were reconstituted in lipid bilayer. Thus, physical and functional interactions between PC2 and alpha-actinin may play an important role in abnormal cell adhesion, proliferation and migration observed in ADPKD.
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PMID:Alpha-actinin associates with polycystin-2 and regulates its channel activity. 1584 96

We first identified Bves (blood vessel/epicardial substance) as a transmembrane protein that localized to the lateral compartment of the epithelial epicardium. Bves traffics to sites of cell-cell contact in cultured epicardial cells and promotes adhesion following transfection into non-adherent fibroblastic L-cells, reminiscent of a cell adhesion molecule. Currently, no function for Bves in relation to epithelial cell adhesion has been identified. We hypothesize that Bves plays a role at cell junctions to establish and/or modulate cell adhesion or cell-cell interactions in epithelial cell types. In this study, we demonstrate that Bves regulates epithelial integrity and that this function may be associated with a role at the tight junction (TJ). We report that Bves localizes with ZO-1 and occludin, markers of the TJ, in polarized epithelial cell lines and in vivo. We find that the behavior of Bves following low Ca2+ challenge or TPA treatment mimics that observed for ZO-1 and is distinct from adherens junction proteins such as E-cadherin. Furthermore, GST pull-down experiments show an interaction between ZO-1 and the intracellular C-terminal tail of Bves. Finally, we demonstrate that Bves modulates tight junction integrity, as indicated by the loss of transepithelial resistance and junction protein localization at the membrane following Bves knock-down in cultured cells. This study is the first to identify a function for Bves in epithelia and supports the hypothesis that Bves contributes to establishment and/or maintenance of epithelial cell integrity.
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PMID:Bves modulates epithelial integrity through an interaction at the tight junction. 1618 40

ST14 (suppression of tumorigenicity 14) is a transmembrane serine protease that contains a serine protease catalytic (SP) domain, an SEA domain, two complement subcomponent C1r/s (CUB) domains, and four low density lipoprotein receptor class A domains. Glutathione S-transferase fusion proteins with SP, CUB, and low density lipoprotein receptor domains and their corresponding mutants were generated to analyze protein interactions with these domains. Modified glutathione S-transferase pull-down assays demonstrated the interaction between the SP domain and hepatocyte growth factor activator inhibitor-1. With the same method, a CUB domain-interacting protein was isolated and turned out to be the transmembrane protein with epidermal growth factor-like and two follistatin-like domains 1 (TMEFF1). Quantitative real time PCR revealed that the expression of the TMEFF1 gene was dependent on the transfection of the ST14 gene in the RKO cell line. Our results also suggested that ST14 and TMEFF1 were co-expressed in the human breast cancer cell line MCF7, human placenta, kidney, and liver tissues. Interestingly, these two genes were co-up-regulated in kidney tumors versus normal tissues, consistent with our results that showed the dependence of TMEFF1 expression on ST14 in RKO cells. Finally, homology modeling studies suggested that TMEFF1 might form a complex with ST14 by an interaction between epidermal growth factor and CUB domains.
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PMID:Protein interaction analysis of ST14 domains and their point and deletion mutants. 1640 23

The coxsackievirus and adenovirus receptor (CAR) is a transmembrane protein important for viral binding to target cells. Using RT-PCR, Western analysis, GST pull-down assay and indirect immunofluorescence, it was shown that CAR is expressed in male germ cells from mice, rats, and humans. CAR was detected in round spermatids in the testis as well as in purified, mature spermatozoa. The two membrane-bound isoforms of CAR occupied different subcellular sites in the acrosomal region of the spermatozoa. CAR was exposed on the surface of acrosome-reacted, but not acrosome-intact cells. Two CAR-binding proteins belonging to the ligand-of-numb protein-X (LNX) family also occupied distinct regions in spermatozoa. Finally, co-immunoprecipitation experiments demonstrated an interaction between CAR and JAM-C, a protein required for spermatid differentiation. Together, these findings imply a function for CAR in male fertility. The results also suggest that CAR in spermatozoa is inaccessible to adenovirus-based gene therapy vectors, and that the risk of germ line infection therefore is low.
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PMID:Coxsackievirus and adenovirus receptor (CAR) is expressed in male germ cells and forms a complex with the differentiation factor JAM-C in mouse testis. 1641 1

We identified a direct interaction between the neuronal transmembrane protein calsyntenin-1 and the light chain of Kinesin-1 (KLC1). GST pulldowns demonstrated that two highly conserved segments in the cytoplasmic domain of calsyntenin-1 mediate binding to the tetratricopeptide repeats of KLC1. A complex containing calsyntenin-1 and the Kinesin-1 motor was isolated from developing mouse brain and immunoelectron microscopy located calsyntenin-1 in association with tubulovesicular organelles in axonal fiber tracts. In primary neuronal cultures, calsyntenin-1-containing organelles were aligned along microtubules and partially colocalized with Kinesin-1. Using live imaging, we showed that these organelles are transported along axons with a velocity and processivity typical for fast axonal transport. Point mutations in the two kinesin-binding segments of calsyntenin-1 significantly reduced binding to KLC1 in vitro, and vesicles bearing mutated calsyntenin-1 exhibited a markedly altered anterograde axonal transport. In summary, our results indicate that calsyntenin-1 links a certain type of vesicular and tubulovesicular organelles to the Kinesin-1 motor.
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PMID:Calsyntenin-1 docks vesicular cargo to kinesin-1. 1676 Apr 30

A monoclonal antibody against Toxoplasma gondii of Tg556 clone (Tg556) blotted a 29 kDa protein, which was localized in the dense granules of tachyzoites and secreted into the parasitophorous vacuolar membrane (PVM) after infection to host cells. A cDNA fragment encoding the protein was obtained by screening a T. gondii cDNA expression library with Tg556, and the full-length was completed by 5'-RACE of 2,086 bp containing an open reading frame (ORF) of 669 bp. The ORF encoded a polypeptide of 222 amino acids homologous to the revised GRA3 but not to the first reported one. The polypeptide has 3 hydrophobic moieties of an N-terminal stop transfer sequence and 2 transmembrane domains (TMD) in posterior half of the sequence, a cytoplasmic localization motif after the second TMD and an endoplasmic reticulum (ER) retrival motif in the C-terminal end, which suggests GRA3 as a type III transmembrane protein. With the ORF of GRA3, yeast two-hybrid assay was performed in HeLa cDNA expression library, which resulted in the interaction of GRA3 with calcium modulating ligand (CAMLG), a type II transmembrane protein of ER. The specific binding of GRA3 and CAMLG was confirmed by glutathione S-transferase (GST) pull-down and immunoprecipitation assays. The localities of fluorescence transfectionally expressed from GRA3 and CAMLG plasmids were overlapped completely in HeLa cell cytoplasm. In immunofluorescence assay, GRA3 and CAMLG were shown to be co-localized in the PVM of host cells. Structural binding of PVM-inserted GRA3 to CAMLG of ER suggested the receptor-ligand of ER recruitment to PVM during the parasitism of T. gondii.
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PMID:Interaction between parasitophorous vacuolar membrane-associated GRA3 and calcium modulating ligand of host cell endoplasmic reticulum in the parasitism of Toxoplasma gondii. 1912 25

To search for calmodulin (CaM) targets, we performed affinity chromatography purification of a rat brain extract using CaM fused with GST as the affinity ligand. Proteomic analysis was then carried out to identify CaM-binding proteins. In addition to identifying 36 known CaM-binding proteins, including CaM kinases, calcineurin, nNOS, the IP(3) receptor, and Ca(2+)-ATPase, we identified an ER transmembrane protein, wolframin [the product of the Wolfram syndrome gene (WFS1)] as interacting. A CaM overlay and an immunoprecipitation assay revealed that wolframin is capable of binding the Ca(2+)/CaM complex in vitro and in transfected cells. Surface plasmon resonance analysis and zero-length cross-linking showed that the N-terminal cytoplasmic domain (residues 2-285) of wolframin binds to an equimolar unit of CaM in a Ca(2+)-dependent manner with a K(D) for CaM of 0.15 muM. Various truncation and deletion mutants showed that the Ca(2+)/CaM binding region in wolframin is located from Glu90 to Trp186. Furthermore, we demonstrated that three mutations (Ala127Thr, Ala134Thr, and Arg178Pro) associated with Wolfram syndrome completely abolished CaM binding of wolframin. This observation may indicate that CaM binding is important for wolframin function and that impairment of this interaction by mutation contributes to the pathology seen in Wolfram syndrome.
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PMID:Identification and characterization of wolframin, the product of the wolfram syndrome gene (WFS1), as a novel calmodulin-binding protein. 1929 54

Dysferlin is a type II transmembrane protein implicated in surface membrane repair in muscle. Mutations in dysferlin lead to limb girdle muscular dystrophy 2B, Miyoshi Myopathy and distal anterior compartment myopathy. Dysferlin's mode of action is not well understood and only a few protein binding partners have thus far been identified. Using affinity purification followed by liquid chromatography/mass spectrometry, we identified alpha-tubulin as a novel binding partner for dysferlin. The association between dysferlin and alpha-tubulin, as well as between dysferlin and microtubules, was confirmed in vitro by glutathione S-transferase pulldown and microtubule binding assays. These interactions were confirmed in vivo by co-immunoprecipitation. Confocal microscopy revealed that dysferlin and alpha-tubulin co-localized in the perinuclear region and in vesicular structures in myoblasts, and along thin longitudinal structures reminiscent of microtubules in myotubes. We mapped dysferlin's alpha-tubulin-binding region to its C2A and C2B domains. Modulation of calcium levels did not affect dysferlin binding to alpha-tubulin, suggesting that this interaction is calcium-independent. Our studies identified a new binding partner for dysferlin and suggest a role for microtubules in dysferlin trafficking to the sarcolemma.
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PMID:Dysferlin interacts with tubulin and microtubules in mouse skeletal muscle. 2040 35

Hedgehog (Hh) signalling is mediated through the Patched-1 (Ptch1) receptor. Hh-binding to Ptch1 blocks the inhibitory effects of Ptch1 on the activity of the transmembrane protein, Smoothened (Smo), resulting induction of target genes by the Gli-family of transcription factors. We demonstrate here that Hh-binding to Ptch1 stimulates activation of Erk1/2. This activation is insensitive to the small molecule Smo antagonists and occurs in a cell line that does not express Smo. Specifically, the C-terminus of Ptch1 harbours motifs encoding Class I and II SH3-binding sites. SH3-domain binding activity was verified using GST-c-src(SH3), -Grb2(SH3) and -p85beta(SH3) fusion-proteins. Ectopically expressed Grb2 or p85beta could also be co-immunoprecipitated with the Ptch1 C-terminus. Addition of Shh to serum-starved human mammary epithelial cells and Shh Light II fibroblasts stimulated phosphorylation of Erk1/2. Erk1/2 activation was observed in cells where Smo activity had been inhibited using cyclopamine and in the breast epithelial cell line, MCF10A, that does not express Smo. These data reveal novel binding activities for the C-terminal region of Ptch1 and define a signalling pathway stimulated by the Hh-ligands operating independently of pathways requiring Smo.
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PMID:Activation of Erk by sonic hedgehog independent of canonical hedgehog signalling. 2045 54

SUMMARY To gain new insights into the signalling mechanisms of the grey mould Botrytis cinerea, which causes several pre- and post-harvest diseases on a variety of host plants, we cloned, sequenced and functionally characterized a gene, btp1, encoding a novel 391-amino acid transmembrane protein. The protein BTP1 shows similarity to the transmembrane protein pth11, which is essential for appressorium formation and successful colonization of plant tissue in the rice blast fungus Magnaporthe grisea. Analyses of the deduced amino acid sequence of btp1 predicted a seven alpha-helical transmembrane topology, which is known to be typical for G protein-coupled receptors (GPCRs) and therefore the protein is thought to play a role in mediation of extracellular signals to intracellular effectors. The gene is located next to the gene bcgstII encoding a new putative glutathione S-transferase, and both genes are transcribed in opposite directions from the same promoter. BcGSTII shows similarity to the glutathione S-transferase GSTII of Schizosaccharomyces pombe, a protein thought to be involved in detoxification of several antifungal drugs. From the sequence similarity of BTP1 to GPCRs, and its expression in planta, we suggested that it might play a role in mediation of plant signals and therefore in pathogenicity. However, targeted gene replacement of btp1 did not result in a phenotype markedly affecting either pathogenicity or sensitivity to chemical stress when compared with the wild-type strain; however, the ten-fold dilution of conidial suspension used for the pathogenicity assay resulted in slight reduction of virulence. Visible symptom development of the mutants on bean plants was also different from the wild-type. The brownish ring, which appears at the margin of secondary lesions in wild-type infections, was brighter and almost absent in Deltabtp1 mutants. Interestingly, deletion of btp1 not only affected the expression of the physically linked bcgstII gene, but in addition the expression of the other two GST-encoding genes in B. cinerea for bcgstI was down-regulated, bcgstII was slightly up-regulated and bcgstIII was strongly up-regulated in the mutant.
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PMID:A novel seven-helix transmembrane protein BTP1 of Botrytis cinerea controls the expression of GST-encoding genes, but is not essential for pathogenicity. 2056 54


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