Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.2 (focal adhesion kinase)
44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Uptake of L-[14C]glutamate (L-[14C]GLU) into nonsynaptic mitochondria isolated from rat cerebral hemispheres was measured in the presence of potential modulators of amino acid transport. The L-GLU carrier agonist 0.2 mM L-aspartate (L-ASP) virtually abolished L-GLU uptake (ASP/GLU concentration ratio, 1:1). L-Arginine (L-ARG) inhibited L-GLU uptake in a dose dependent manner over the concentration range 0.1-5 mM to maximum inhibition of 85%. Putrescine or ammonia had no effect, whereas 5 mM creatine and the NO generator, 5 mM sodium nitroprusside, increased the uptake by 73% and 57%, respectively. D-ARG was three times less effective in inhibiting L-GLU uptake than L-ARG at 5 mM concentration. The L-amino acids ornithine, lysine, histidine, tyrosine, phenylalanine, proline, leucine, isoleucine, tryptophan, glycine, methionine, valine, serine, taurine, alanine or cysteine did not affect the uptake when added in concentrations of 2-5 mM. A 14% inhibition of L-GLU uptake was noted in the presence of L-glutamine (L-GLN) (2 mM) or a dicarboxylate carrier ligand, alpha-ketoglutarate (alpha-KG) (5 mM), and a 30% inhibition with a dicarboxylate carrier inhibitor phenylsuccinate (PhSc) (5 mM). The results suggest that L-ARG functions as a specific endogenous modulator of cerebral mitochondrial L-GLU transport.
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PMID:Glutamate uptake is inhibited by L-arginine in mitochondria isolated from rat cerebrum. 924 41

We found previously that restriction of tyrosine (Tyr) and phenylalanine (Phe) inhibited growth and metastasis of B16BL6 murine melanoma and arrested these cells in the G0-G1 phase of the cell cycle. Here, we report that deprivation of these two amino acids in vitro induces apoptosis in B16BL6 and in human A375 melanoma cells but not in nontransformed, neonatal murine epidermal cells or human infant foreskin fibroblasts. Four days after deprivation of Tyr and Phe in vitro, 37% of B16BL6 and 51% of A375 melanoma cells were undergoing apoptosis. Apoptosis was not associated with elevation in intracellular calcium or alteration in p53 or c-myc protein expression. Expression and Tyr phosphorylation of focal adhesion kinase (FAK) were inhibited in both melanoma cell lines by deprivation of Tyr and Phe but not by deprivation of glutamine or serum. Tyr phosphorylation of FAK in Tyr- and Phe-deprived melanoma cells was enhanced within 30 min of refeeding with complete DMEM. FAK protein expression recovered within 60 min, and cell viability recovered within 24 h. Genistein, a tyrosine kinase inhibitor that specifically inhibits Tyr phosphorylation of FAK, did not induce apoptosis in A375 melanoma cells at a concentration of 50 microM. Genistein prevented the recovery of cell viability upon refeeding with Tyr and Phe to previously deprived A375 melanoma cells. These data collectively indicate that apoptosis induced by Tyr and Phe deprivation is FAK-dependent.
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PMID:Focal adhesion kinase-dependent apoptosis of melanoma induced by tyrosine and phenylalanine deficiency. 997 29

SPI-B is a B lymphocyte-specific Ets transcription factor that shares a high degree of similarity with PU.1/SPI-1. In direct contrast to PU.1(-/-) mice that die in utero and lack monocytes, neutrophils, B cells, and T cells, Spi-B-/- mice are viable and exhibit a severe B cell proliferation defect. Since PU.1 is expressed at wild type levels in Spi-B-/- B cells, the mutant mice provide genetic evidence that SPI-B and PU.1 have at least some non-redundant roles in B lymphocytes. To begin to understand the molecular basis for these defects, we delineated functional domains of SPI-B for comparison to those of PU.1. By using a heterologous co-transfection system, we identified two independent transactivation domains in the N terminus of SPI-B. Interestingly, only one of these domains (amino acids 31-61), a proline/serine/threonine-rich region, unique among Ets proteins, is necessary for transactivation of the immunoglobulin lambda light chain enhancer. This transactivation motif is in marked contrast to PU.1, which contains acidic and glutamine-rich domains. In addition, we describe a functional PU.1 site within the c-FES promoter which SPI-B fails to bind efficiently and transactivate. Finally, we show that SPI-B interacts with the PU.1 cofactors Pip, TBP, c-Jun and with lower affinity to nuclear factor interleukin-6beta and retinoblastoma. Taken together, these data suggest that SPI-B binds DNA with a different affinity for certain sites than PU.1 and harbors different transactivation domains. We conclude that SPI-B may activate unique target genes in B lymphocytes and interact with unique, although currently unidentified, cofactors.
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PMID:SPI-B activates transcription via a unique proline, serine, and threonine domain and exhibits DNA binding affinity differences from PU.1. 1019 96

Hyperglycemia is responsible for many of the vascular complications and metabolic derangements seen in diabetes. One potential regulator of the effects of glucose is the hexosamine biosynthesis pathway (HBP). Glutamine: fructose-6-phosphate amidotransferase (GFA), the first and rate-limiting enzyme in this pathway, catalyzes the transfer of an amino group from glutamine to fructose-6-phosphate to form glucosamine-6-phosphate. Overexpression of GFA in rat-1 fibroblasts results in insulin resistance for glycogen synthase (GS) activity, and renders these cells more sensitive to the effects of glucose. Using rat-1 cells, we examine further the mechanisms whereby hexosamines lead to insulin resistance. Insulin stimulated GS activity was found to occur via a PI-3 kinase (PI-3K)-dependent pathway as wortmannin, an inhibitor of PI-3K, blocked insulin's ability to stimulate GS activity. Subsequently, we examined the effects of hexosamines on PI-3K and Akt/PKB activity. Cells were cultured in 1 mM glucose (low glucose, LG), 20 mM glucose (high glucose, HG), or 1 mM glucose plus 3 mM glucosamine (GlcN) for 16--20 h. After treatment with insulin (100 nM) for 5 min, cell extracts were assayed for IRS-1 associated and total PI-3K activity. At LG, insulin increased PI-3K activity by 43%. There was no insulin stimulation of PI-3K activity in cells cultured in HG or GlcN. There was a trend for IRS-1 protein levels to decrease in HG but not GlcN. PI-3K protein levels were not altered by HG or GlcN. Finally PKB activity was assayed. At LG, insulin stimulated PKB activity. Again, both HG and GlcN significantly reduced insulin's ability to stimulate PKB activity. We conclude that the hexosamine-mediated insulin resistance of GS activity seen in rat-1 cells is mediated by hexosamine regulation of PI-3K and PKB.
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PMID:Glucose-induced insulin resistance of phosphatidylinositol 3'-OH kinase and AKT/PKB is mediated by the hexosamine biosynthesis pathway. 1127 5

The NGFI-B (Nur77) subfamily of orphan nuclear receptors (NRs), which also includes Nurr1 and NOR1, bind the NurRE regulatory element as either homo- or heterodimers formed between subfamily members. These NRs mediate the activation of pituitary proopiomelanocortin (POMC) gene transcription by the hypothalamic hormone corticotropin-releasing hormone (CRH), an important link between neuronal and endocrine components of the hypothalamo-pituitary-adrenal axis. CRH effects on POMC transcription do not require de novo protein synthesis. We now show that CRH signals activate Nur factors through the cyclic AMP/protein kinase A (PKA) pathway. CRH and PKA rapidly increase nuclear DNA binding activity of NGFI-B dimers but not monomers. Accordingly, CRH- or PKA-activated Nur factors enhance dimer (but not monomer) target response elements. We also show that p160/SRC coactivators are recruited to Nur dimers (but not to monomers) and that coactivator recruitment to the NurRE is enhanced in response to CRH. Moreover, PKA- and coactivator-induced potentiation of NGFI-B activity are primarily exerted through the N-terminal AF-1 domain of NGFI-B. The TIF2 (SRC-2) glutamine-rich domain is required for this activity. Taken together, these results indicate that Nur factors behave as endpoint effectors of the PKA signaling pathway acting through dimers and AF-1-dependent recruitment of coactivators.
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PMID:Dimer-specific potentiation of NGFI-B (Nur77) transcriptional activity by the protein kinase A pathway and AF-1-dependent coactivator recruitment. 1252 83

Inhibition of autophagic proteolysis by hypoosmotic or amino acid-induced hepatocyte swelling requires osmosignaling toward p38MAPK; however, the upstream osmosensing and signaling events are unknown. These were studied in the intact perfused rat liver with a preserved in situ environment of hepatocytes. It was found that hypoosmotic hepatocyte swelling led to an activation of Src (but not FAK), Erks, and p38MAPK, which was prevented by the integrin inhibitory hexapeptide GRGDSP, but not its inactive analogue GRGESP. Src inhibition by PP-2 prevented hypoosmotic MAP kinase activation, indicating that the integrin/Src system is located upstream in the osmosignaling toward p38MAPK and Erks. Inhibition of the integrin/Src system by the RGD motif-containing peptide or PP-2 also prevented the inhibition of proteolysis and the decrease in autophagic vacuole volume, which is otherwise observed in response to hypoosmotic or glutamine/glycine-induced hepatocyte swelling. These inhibitors, however, did not affect swelling-independent proteolysis inhibition by phenylalanine. In line with a role of p38MAPK in triggering the volume regulatory decrease (RVD), PP-2 and the RGD peptide blunted RVD in response to hypoosmotic cell swelling. The data identify integrins and Src as upstream events in the osmosignaling toward MAP kinases, proteolysis, and RVD. They further point to a role of integrins as osmo- and mechanosensors in the intact liver, which may provide a link between cell volume and cell function.
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PMID:Involvement of integrins in osmosensing and signaling toward autophagic proteolysis in rat liver. 1272 Dec 89

Androgen-independent prostate cancer is resistant to therapy and is often metastatic. Here we studied the effect of deprivation of tyrosine and phenylalanine (Tyr/Phe), glutamine (Gln), or methionine (Met), in vitro on human DU145 and PC3 androgen-independent prostate cancer cells, and on nontumorigenic human infant foreskin fibroblasts and human prostate epithelial cells. Deprivation of the amino acids similarly inhibited growth of DU145 and PC3 cells, arresting the cell cycle at G0/G1. Met and Tyr/Phe deprivation induces apoptosis in DU145, but only Met deprivation induces apoptosis in PC3 cells. The growth of normal cells is inhibited, but no apoptosis is induced by amino acid deprivation. Tyr/Phe deprivation inhibits expression and phosphorylation of focal adhesion kinase (FAK) and extracellular-regulated kinase (ERK) in DU145 but not PC3 or normal cells. Met deprivation inhibits phosphorylation but not protein expression of FAK and ERK in PC3. Therefore, apoptosis of DU145 and PC3 cells by amino acid restriction is FAK and ERK dependent. Tyr/Phe and Met deprivation inhibits invasion of DU145 and PC3, but Gln deprivation only inhibits invasion of DU145 cells. This indicates that the inhibition of invasion is not dependent on induction of apoptosis. The inhibition of invasion by Tyr/Phe restriction in DU145 and Met restriction in PC3 is consistent with the inhibition on FAK/ERK signaling. The inhibition of Tyr/Phe restriction in PC3 and Gln restriction in DU145 is not associated with inhibition of FAK/ERK. This indicates that FAK/ERK-dependent and independent pathways are modulated by specific amino acid restriction. This study shows the potential for specific amino acid restriction to treat prostate cancer.
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PMID:Specific amino acid dependency regulates invasiveness and viability of androgen-independent prostate cancer cells. 1279 6

The degree of sequence conservation of arginine repressor proteins (ArgR) and of the cognate operators (tandem pairs of 18 bp imperfect palindromes, ARG boxes) in evolutionarily distant bacteria is unusually high, and the global mechanism of ArgR-mediated regulation appears to be similar. However, here we demonstrate that the arginine repressor from the hyperthermophilic bacterium Thermotoga neapolitana (ArgR(Tn)) exhibits characteristics that clearly distinguish this regulator from the well-studied homologues from Escherichia coli, Bacillus subtilis and B.stearothermophilus. A high-resolution contact map of ArgR(Tn) binding to the operator of the biosynthetic argGHCJBD operon of Thermotoga maritima indicates that ArgR(Tn) establishes all of its strong contacts with a single ARG box-like sequence of the operator only. Protein array and electrophoretic mobility-shift data demonstrate that ArgR(Tn) has a remarkable capacity to bind to arginine operators from Gram-negative and Gram-positive bacteria, and to single ARG box-bearing targets. Moreover, the overall effect of L-arginine on the apparent K(d) of ArgR(Tn) binding to various cognate and heterologous operator fragments was minor with respect to that observed with diverse bacterial arginine repressors. We demonstrate that this unusual behaviour for an ArgR protein can, to a large extent, be ascribed to the presence of a serine residue at position 107 of ArgR(Tn), instead of the highly conserved glutamine that is involved in arginine binding in the E.coli repressor. Consistent with these results, ArR(Tn) was found to behave as a superrepressor in E.coli, inhibiting growth in minimal medium, even supplemented with arginine, whereas similar constructs bearing the S107Q mutant allele did not inhibit growth. We assume that ArgR(Tn), owing to its broad target specificity and its ability to bind single ARG box sequences, might play a more general regulatory role in Thermotoga
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PMID:Hyperthermophilic Thermotoga arginine repressor binding to full-length cognate and heterologous arginine operators and to half-site targets. 1296 66

Cytotoxic necrotizing factor type 1 (CNF1) from Escherichia coli activates the small GTP-binding proteins of the Rho family (Rho, Rac, and Cdc42) by catalyzing their deamidation at a specific glutamine residue. Since RhoA, Rac, and Cdc42 play a pivotal role in cell migration during the early phase of wound repair, we investigated whether CNF1 was able to interfere with wound healing in intestinal epithelial monolayers (T84 cells). After mechanical injury, we found that CNF1 blocks epithelial wound repair within 48 h. This effect was characterized by cell elongation and filopodium formation on the leading edge, in association with permanent phosphorylation of the focal adhesion kinase (FAK) via Rho activation. Moreover, inhibition of Rho kinase with Y-27632 decreased CNF1-mediated permanent FAK phosphorylation, leading to complete restitution of wound repair within 24 h. In addition, we found that CNF1 induced upregulation of mitogen-activated protein kinases (MAPK) activation. Moreover, activation of Rac and MAPK by CNF1 increased matrix metalloproteinase 9 expression in wounded T84 monolayers. Taken together, these results provide evidence that CNF1 strongly impairs intestinal epithelial wound healing.
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PMID:Escherichia coli cytotoxic necrotizing factor 1 inhibits intestinal epithelial wound healing in vitro after mechanical injury. 1538 72

We had previously found that selective restriction of amino acids inhibits invasion of human A375 melanoma. Integrins, cell surface receptors for the components of extracellular matrix (ECM), are activated during cell adhesion and spreading, and initiate signaling pathways that control growth and invasion of tumor cells. We examined the effect of tyrosine (Tyr) and phenylalanine (Phe), methionine (Met) or glutamine (Gln) restriction on attachment and spreading of A375 and MeWo melanoma cell lines on fibronectin and laminin. In A375 cells, restriction of Tyr/Phe or Met inhibited attachment to and spreading on laminin and fibronectin, inhibited alpha3 and alpha4 integrin expression, and inhibited accumulation of FAK-Tyr397 and F-actin at leading edges of cell protrusions. Tyr/Phe restriction also inhibited attachment-induced autophosporylation of FAK-Tyr397. In MeWo cells, the order of inhibition by amino acid restriction on cell attachment and spreading was as follows: Gln > Tyr/Phe > Met. Restriction of Gln reduced alpha5 integrin expression. All amino acid restrictions similarly inhibited phosphorylation of FAK-Tyr397, FAK-Tyr577, FAK-Tyr861 and paxillin-Tyr31. Gln restriction exhibited the strongest inhibition of actin cytoskeleton remodeling during the cell spreading. The present study reveals that specific amino acid restriction inhibits attachment and spreading of melanoma via inhibition of specific integrin expression, inhibition of integrin-mediated FAK phosphorylation, and modulation of actin cytoskeleton remodeling. These data provide additional understanding of the mechanism by which specific amino acid restriction controls invasion and migration of melanoma.
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PMID:Specific amino acid restriction inhibits attachment and spreading of human melanoma via modulation of the integrin/focal adhesion kinase pathway and actin cytoskeleton remodeling. 1578 96


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