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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)
Changes in cellular growth and dramatic alterations in cell morphology and adhesion are common features of cells transformed by oncogenic protein tyrosine kinases, such as pp60src and other members of the Src family. In this report, we present evidence for the stable association of two Src family kinases (pp60src and pp59fyn) with tyrosine-phosphorylated forms of a focal adhesion-associated protein tyrosine kinase,
pp125FAK
. In Src-transformed chicken embryo cells, most of the
pp125FAK
was stably complexed with activated pp60src (e.g., pp60(527F). The stable association of
pp125FAK
with pp60(527F) in vivo required the structural integrity of the Src SH2 domain. The association of pp60(527F) and
pp125FAK
could be reconstituted in vitro by incubation of normal cell extracts with
glutathione S-transferase
fusion proteins containing SH2 or SH3/SH2 domains of pp60src. Furthermore, the association of isolated SH2 or SH3/SH2 domains with in vitro 32P-labeled
pp125FAK
protected the major site of
pp125FAK
autophosphorylation from digestion with a tyrosine phosphatase, indicating that the autophosphorylation site of
pp125FAK
participates in binding with Src. Immunoprecipitation of Src family kinases from extracts of normal chicken embryo cells revealed stable complexes of pp59fyn and tyrosine-phosphorylated
pp125FAK
. These data provide evidence for a direct interaction between two cytoplasmic nonreceptor protein tyrosine kinases and suggest that Src may contribute to changes in
pp125FAK
regulation in transformed cells. Furthermore,
pp125FAK
may directly participate in the targeting of pp59fyn or possibly other Src family kinases to focal adhesions in normal cells.
...
PMID:Stable association of pp60src and pp59fyn with the focal adhesion-associated protein tyrosine kinase, pp125FAK. 750 91
Focal adhesion kinase (
pp125FAK
) is localized to focal adhesions and tyrosine phosphorylated by the engagement of beta 1 integrins. However, it is unclear how
pp125FAK
is linked to integrin molecules. We demonstrate that
pp125FAK
is directly associated with paxillin, a 68-kD cytoskeleton protein. The COOH-terminal domain of
pp125FAK
spanning
FAK
residues 919-1042 is sufficient for paxillin binding and has vinculin-homologous amino acids, which are essential for paxillin binding. Microinjection and subsequent immunohistochemical analysis reveal that
glutathione S-transferase
-
FAK
fusion proteins, which bind to paxillin, localize to focal adhesions, whereas fusion proteins with no paxillin-binding activity do not localize to focal adhesions. These findings strongly suggest that
pp125FAK
is localized to focal adhesions by the direct association with paxillin.
...
PMID:Direct association of pp125FAK with paxillin, the focal adhesion-targeting mechanism of pp125FAK. 756 82
pp125(
FAK
) and CAKbeta/Pyk2/CadTK/RAFTK are related protein-tyrosine kinases. It is therefore of interest whether CAKbeta shares some of the properties of pp125(
FAK
). Using recombinant
glutathione S-transferase
fusion proteins, we show that the C-terminal domains of both proteins bind paxillin in vitro. The C-terminal domain of CAKbeta was engineered to be autonomously expressed in chicken embryo cells and, like pp125(
FAK
) and p41/43(FRNK) (the C-terminal noncatalytic domain of pp125(
FAK
)), was found to localize to cellular focal adhesions. In contrast, full-length CAKbeta was generally found diffusely distributed throughout the cell, although a fraction of the cells exhibited focal adhesion localization. Vanadate treatment of pp125(
FAK
)- and CAKbeta-overexpressing CE cells induced a dramatic increase in the phosphotyrosine content of a common set of proteins including tensin, paxillin, and p130(Cas), but some of these substrates, particularly p130(Cas), appeared to be differentially phosphorylated by pp125(
FAK
) and CAKbeta. Levels of tyrosine phosphorylation were higher in CAKbeta-overexpressing cells, and additional phosphotyrosine-containing species were specifically immunoprecipitated. In addition, vanadate treatment of CE cells overexpressing CAKbeta, but not pp125(
FAK
) overexpressors, induced a profound morphological change, which could be a consequence of the observed differences in substrate phosphorylation.
...
PMID:Differential signaling by the focal adhesion kinase and cell adhesion kinase beta. 931 50
We have previously reported that non-activated platelets can be induced by morphological changes from the recombinant fusion protein of
GST
-rhodostomin [
GST
-RHO(RGD)], a member of disintegrin with an arginine-glycine-aspartic acid (RGD) motif. In this study, we further characterized the factors involved in platelet shape changes induced by rhodostomin. From less to full-spreading, four cell spreading indexes, p1, p2, s1 and s2, were designated to the platelet shape based on the scanning electron micrographs. Results of peptide competition and antibody blocking confirmed that interaction between the RGD of rhodostomin and the alpha(IIb)beta3 integrins of platelets was required for induction of a higher percentage of s2 cells. When platelets were pretreated with calphostin C, herbimycin A and cytochalasin B, respectively, the percentage of p1 and p2 cells on rhodostomin-coated plates was increased and, concomitantly, the percentage of s1 and s2 cells was decreased. Biochemical analyses indicated that the focal adhesion kinase (
FAK
or
pp125FAK
) in platelets that adhered to
GST
-RHO(RGD) was phosphorylated in contrast to little or no phosphorylation of
FAK
in cells adhered to fibrinogen or non-activated cells. Furthermore, the degree of
FAK
phosphorylation was consistently correlated with morphological changes in platelets treated with various drugs. Taking all the results together, we suggested that rhodostomin could directly bind to integrins of platelets and then trigger signal transduction leading to
FAK
phosphorylation and actin polymerization and finally resulting in platelet full-spreading.
...
PMID:Full-spreading platelets induced by the recombinant rhodostomin are via binding to integrins and correlated with FAK phosphorylation. 969 Jul 77
Freshly isolated peripheral blood monocytes lack focal adhesion kinase (p125(
FAK
)) but activate a second member of this kinase family, calcium-dependent tyrosine kinase (CADTK; also known as Pyk2/CAKbeta/RAFTK/FAK2), upon adhesion or stimulation with chemokines. To study the role of CADTK in monocyte adherence and motility, we performed immunocytochemical localization that showed CADTK at the leading edge and ruffling lamellipodial structures in freshly isolated, adhered human monocytes. We next introduced CADTK/CAKbeta-related non-kinase (CRNK), the C-terminal noncatalytic domain of CADTK, into monocytes by electroporation and showed that it inhibited CADTK autophosphorylation. Introduction of the fusion protein
glutathione S-transferase
(
GST
)-CRNK also reduced (i) cell spreading, as reflected in a reduced cell area 30 min after adhesion, (ii) adhesion-induced phosphotyrosine increases and redistribution into lamellipodia, and (iii) adhesion-induced extracellular signal-regulated protein kinase (ERK) activation. In control experiments, introduction of
GST
or
GST
-C3 transferase (an inhibitor of RhoA GTPase activity) by electroporation did not affect these parameters. Monocytes adhered in the presence of autologous serum were highly motile even after introduction of
GST
(83% motile cells). However, only 26% of monocytes with introduced
GST
-CRNK were motile. In contrast,
GST
-CRNK-treated monocytes were fully capable of phagocytosis and adhesion-induced cytokine gene induction, suggesting that CADTK is not involved in these cellular activities and that
GST
-CRNK introduction does not inhibit global monocyte functions. These results suggest that CADTK is crucial for the in vitro monocyte cytoskeletal reorganization necessary for cell motility and is likely to be required in vivo for recruitment to sites of inflammation.
...
PMID:Inhibition of the calcium-dependent tyrosine kinase (CADTK) blocks monocyte spreading and motility. 1106 41
SNARK, the fourth member of the AMPK catalytic subunit family, was originally identified in a rat kidney cDNA library, and in this study we isolated its human homologue. A BLAST search analysis using rat SNARK protein yielded a single high homology clone, DKFZp434J037, isolated from human testis, and since its hypothetical protein showed 84% homology to rat SNARK protein, we assumed DKFZp434J037 to be the human SNARK cDNA. The human SNARK cDNA is 3443bp long and encodes a 628 amino acid protein having an estimated molecular weight of 69kDa, and its chromosomal localization had been assigned to 1q32.1. The same as other members of AMPK catalytic subunit family, human SNARK showed AMP-dependent
GST
-SAMS phosphorylation activity and enhanced HepG2 cell survival during glucose starvation. Human SNARK-overexpressing HepG2 cells (H/SNK) showed acute cell-cell detachment when exposed to glucose-free medium and the cell-cell detachment correlated well with the detection of G-actin. Deletion mutant analysis strongly suggested that the putative catalytic domain of SNARK is necessary for the cell-cell detachment, and Western blotting analysis showed that phosphorylation of
FAK
and PKC, which were dramatically increased by glucose starvation in HepG2 cells, was markedly suppressed by SNARK.
...
PMID:Induction of cell-cell detachment during glucose starvation through F-actin conversion by SNARK, the fourth member of the AMP-activated protein kinase catalytic subunit family. 1457 7
Lipid phosphate phosphohydrolase-3 (LPP3) is a cell surface protein that exhibits ectoenzyme activity. Previously, we identified human LPP3 in a functional assay of angiogenesis and showed that the Arg-Gly-Asp (RGD) motif in the proposed second extracellular domain interacts with a subset of integrins to mediate cell-cell adhesion. In contrast to the RGD domain of human LPP3, murine Lpp3 contains a variant sequence, Arg-Gly-Glu (RGE). Whether the RGE motif of murine Lpp3 mediates cell-cell interaction has not been studied. In this report, we test the hypothesis that the cell adhesion function of the LPP3 protein is conserved across mouse and human. A
glutathione S-transferase
(
GST
) fusion protein of the proposed second extracellular loop of the murine Lpp3 sequence (
GST
-mLpp3-RGE) promoted attachment of cells in a long-term cell adhesion assay.
GST
-mLpp3-RGE interacted with alpha(5)beta(1) and alpha(v)beta(3) integrins in a solid-phase ELISA, while a mutant control,
GST
-hLPP3-RAD, did not. Long-term adhesion of endothelial cells to
GST
-mLpp3-RGE induced phosphorylation of
FAK
, SHC, and CAS, whereas adhesion to
GST
-hLPP3-RAD failed to do so. Upon long-term adhesion both the
GST
-hLPP3-RGD and
GST
-mLpp3-RGE substrates bound to the alpha(5)beta(1) integrin of FRT-alpha(5)(+) cells, an interaction that was inhibited by an anti-alpha(5) integrin antibody. In addition, a cell aggregation assay showed that the intact mLpp3-RGE protein interacts with alpha(5)beta(1) and alpha(v)beta(3) integrins expressed by adjacent cells, an interaction that can be blocked by GRGDSP peptides and anti-LPP3-RGD antibodies. These data, together with the known importance of integrins in angiogenesis, provide a mechanism for the function of LPP3 in cell-cell interactions in both human and mouse.
...
PMID:Murine lipid phosphate phosphohydrolase-3 acts as a cell-associated integrin ligand. 1609 22
ARHGAP21 is highly expressed in the heart, which demonstrates activity over Cdc42 and interacts with proteins of the cytoskeleton and adherent junctions. The main cause of cardiac hypertrophy is mechanical stimulus; therefore we analyzed ARHGAP21 expression after acute mechanical stress in the myocardium and its association with
FAK
and PKCzeta. We demonstrated that ARHGAP21 is relocated to Z-lines and costameres after pressure overload, and interacts with PKCzeta and
FAK
in control rats (sham), rats submitted to aortic clamping and spontaneously hypertensive rats (SHR). Co-transfection using ARHGAP21 and PKCzeta constructions demonstrated that ARHGAP21 associates with PKCzeta-
GST
and endogenous
FAK
. Pulldown assay showed that ARHGAP21 binds to the C-terminal region of
FAK
. Moreover, ARHGAP21 binds to PKCzeta phosphorylated on Thr410 in sham and SHR. However, ARHGAP21 only binds to
FAK
phosphorylated on Tyr925 of SHR. Additionally, PKCzeta is phosphorylated by mechanical stimuli. These results suggest that ARHGAP21 may act as a signaling or scaffold protein of
FAK
and PKCzeta signaling pathways, developing an important function during cardiac stress.
...
PMID:ARHGAP21 associates with FAK and PKCzeta and is redistributed after cardiac pressure overload. 1866 71
Upon growth factor stimulation, the scaffold protein, Gab1, is tyrosine phosphorylated and subsequently the adaptor protein, Crk, transmits signals from Gab1. We have previously shown that Crk overexpression, which is detectable in various human cancers, induces tyrosine phosphorylation of Gab1 without extracellular stimuli. In the present study, the underlying mechanisms were further investigated. Mutational analyses of CrkII demonstrated that the SH2 domain, but not the SH3(N) or the regulatory Y221 residue of CrkII, is critical for the induction of Gab1-Y307 phosphorylation. SH2 mutation of CrkII also decreased the interaction with Gab1. In
GST
pull-down assay, Crk-SH2 bound to wild-type Gab1, whereas Crk-SH3(N) interacted with the Gab1 mutant, which lacks the clustered tyrosine region (residues 242-410). Tyrosine phosphorylation of Gab1 was induced by all Crk family proteins, but not other SH2-containing signalling adaptors. Src-family kinase inhibitor, PP2, abrogates Crk-induced tyrosine phosphorylations of Gab1. Y307 phosphorylation was undetectable in fibroblasts lacking Src, Yes, and Fyn, even upon overexpression of Crk, whereas cells lacking only Yes and Fyn still contained Gab1 with phosphorylated Y307. Furthermore, Crk induced the phosphorylation of Src-Y416; accordingly the interaction between Crk and Csk was increased. The Gab1-Y307F mutant failed to localize near the plasma membrane even upon HGF stimulation and decreased cell migration. Moreover, Gab1-Y307F disturbed the localization of Crk,
FAK
, and paxillin, which are the typical components of focal adhesions. Taken together, these results indicate that Crk facilitates tyrosine phosphorylation of Gab1-Y307 through Src, contributing to the organization of focal adhesions and enhanced cell migration, thereby possibly promoting human cancer development.
...
PMID:Crk adaptor protein-induced phosphorylation of Gab1 on tyrosine 307 via Src is important for organization of focal adhesions and enhanced cell migration. 1935 53
VEGF (vascular endothelial growth factor)-C is a major growth factor implicated in various physiological processes, such as angiogenesis and lymphangiogenesis. In the present paper, we report the identification of three short VEGF-C splicing isoforms (VEGF-C62, VEGF-C129 and VEGF-C184) from immortalized mouse kidney PTECs (proximal tubular epithelial cells). Semi-quantitative RT (reverse transcription)-PCR analysis showed these isoforms were universally expressed to varying degrees in different tissues with high expression levels in the kidney. In immortalized PTECs and podocytes, VEGF-C62 can activate phosphorylation of
FAK
(focal adhesion kinase) and promote cell adhesion to substratum. Cell survival was also increased by VEGF-C62 treatment in the absence of serum. VEGF-C62 can also reduce cell proliferation in PTECs and podocytes. Nucleolin was one of the proteins that associated with VEGF-C62 in pull-down assays using
GST
(
glutathione transferase
) fusion proteins as bait, indicating different protein binding requirements for VEGF-C62 compared with VEGF-C. In conclusion, these newly identified VEGF-C isoforms represent a new class of proteins, which are potentially involved in epithelial cell adhesion and proliferation through novel receptor pathways.
...
PMID:Characterization of novel VEGF (vascular endothelial growth factor)-C splicing isoforms from mouse. 2041 67
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