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)

High affinity IgE receptors (alpha beta gamma 2) mediate the activation of the non-receptor tyrosine kinases Lyn and Syk. Here we show that the antioxidant drug N-acetyl-L-cysteine (NAC) inhibits antigen-mediated Syk activation whereas Lyn activation and phosphorylation of beta and gamma is maintained. Furthermore, NAC inhibits antigen-mediated calcium mobilization and exocytosis in a dose-dependent manner, but does not inhibit ionomycin-induced exocytosis. These data support a model in which the activation of Lyn is responsible for receptor phosphorylation and precedes the activation of Syk. The inhibition of Syk activation by NAC may be relevant to B and T cell antigen receptors, which are also linked to Syk/ZAP70 tyrosine kinases.
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PMID:N-acetyl-L-cysteine inhibits antigen-mediated Syk, but not Lyn tyrosine kinase activation in mast cells. 800 75

Previously, we characterized the prostaglandin (PG) F2 alpha receptor linked to phospholipase C activation and DNA synthesis in NIH-3T3 cells (Nakao, A., Watanabe, T., Taniguchi, S., Nakamura, M., Honda, Z-I., Shimizu, T., and Kurokawa, K. (1993) J. Cell. Physiol. 155, 257-264). To elucidate intracellular events evoked via this receptor, we examined changes caused by PGF2 alpha stimulation in the phosphotyrosine composition of cellular proteins. The addition of PGF2 alpha to cells in quiescent culture rapidly increased the levels of phosphotyrosine in cellular proteins with Mr values of 70,000 (pp70), 85,000 (pp85), 92,000 (pp92), 100,000 (pp100), and 125,000 (pp125); the latter was immunologically identified as p125 focal adhesion kinase. The PGF2 alpha-induced changes in the level of intracellular Ca2+ ([Ca2+]i) elevation, formation of inositol phosphates, and [3H]thymidine incorporation followed a similar dose dependence as PGF2 alpha-induced tyrosine phosphorylation. This tyrosine phosphorylation was independent of extracellular Ca2+, while a [Ca2+]i chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (50 microM), completely inhibited the PGF2 alpha-induced elevation of [Ca2+]i, tyrosine phosphorylation, and [3H]thymidine incorporation. Ionomycin (0.1 microM), which induced [Ca2+]i elevation without formation of inositol phosphates, mimicked the PGF2 alpha-induced tyrosine phosphorylation. 12-O-Tetradecanoylphorbol-13-acetate (TPA) also induced [3H]thymidine incorporation in a dose-dependent manner but had no significant effect on tyrosine phosphorylation. The PGF2 alpha-induced tyrosine phosphorylation could be observed even in the cells pretreated with TPA (5 microM, 24 h). PGF2 alpha exhibited an additive effect on TPA-induced [3H]thymidine incorporation but had no effect on the 32P-phosphorylation of a known 80-kDa protein kinase (PK) C substrate. Both staurosporine and H-7 inhibited the PGF2 alpha-induced increase in [3H]thymidine incorporation and tyrosine phosphorylation in a similar dose-dependent manner whether or not cells were pretreated with TPA (5 microM, 24 h). However, W-7 and KN-62 had no effect on these cellular responses even at the concentration for the almost complete inhibition of Ca2+/calmodulin-dependent PKs (20 microM). These results, taken together, indicate that PGF2 alpha receptor-mediated tyrosine phosphorylation is evoked by a [Ca2+]i-dependent mechanism that is sensitive to staurosporine and H-7 but which is independent of PKC or Ca2+/calmodulin PKs. Finally, the data suggest that this PGF2 alpha-induced signaling pathway is linked to the proliferation of cells.
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PMID:Prostaglandin F2 alpha enhances tyrosine phosphorylation and DNA synthesis through phospholipase C-coupled receptor via Ca(2+)-dependent intracellular pathway in NIH-3T3 cells. 802 Dec 71

The relationship of DNA fragmentation to the greatly enhanced cytotoxicity seen in vitro against tumour cells when recombinant human tumour necrosis factor-alpha (TNF-alpha) is combined with hyperthermia was investigated. The TNF-alpha-sensitive L929 and -resistant EMT6 cells were treated with 8.8 and 16 ng of TNF-alpha per ml, respectively, and then heated at 40.5 degrees C for 24 h (L929) or at 43 degrees C for 1 h (L929) or 1.5 h (EMT-6) beginning 1 h later. For both cell lines at both temperatures, the addition of heating to the TNF-alpha treatment significantly decreased viability and increased DNA fragmentation at earlier time points than seen with either TNF-alpha or heat alone. DNA fragmentation was further studied using agarose gel electrophoresis to examine the size distribution of the DNA fragments and the ability of intracellular calcium buffering agents BAPTA and quin-2 to inhibit fragmentation. At 4.5 h after L929 cells were treated with TNF-alpha at 43 degrees C, the size distribution of DNA fragments more closely resembled the oligonucleosome sized apoptotic DNA fragmentation, as seen in irradiated rat thymocytes, than the spectrum of DNA fragments seen in necrotic fragmentation. However, while BAPTA and quin-2 inhibited the calcium-dependent apoptotic fragmentation seen in thymocytes they did not inhibit the DNA fragmentation in L929 cells. In addition, the loss of membrane integrity in both L929 and EMT-6 cells preceded or approximated the appearance of DNA fragmentation, whereas loss of membrane integrity usually follows DNA fragmentation in apoptosis. However, morphological studies showed that apoptotic bodies were present in L929 cell cultures treated with TNF-alpha and heat, and were distinguishable from necrosing cells. We conclude that both types of DNA fragmentation are operant in some cell lines exhibiting a cytotoxic response to TNF-alpha and heat treatments, and that increased fragmentation reflects the greatly enhanced cytotoxic interactions seen with combination treatments in those cells.
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PMID:Cytotoxic manifestations of the interaction between hyperthermia and TNF: DNA fragmentation. 806 83

The neuro-intestinal peptide hormone cholecystokinin (CCK)/gastrin has been suggested to have a trophic effect on gastro-intestinal tract in vivo as well as in vitro. In the present study, the human CCK-B/gastrin receptor was expressed in mouse NIH3T3 fibroblasts to investigate the molecular basis of signal transduction pathway of the guanine nucleotide regulatory protein (G protein)-coupled receptor. Human CCK-B/gastrin receptor expressed in NIH3T3 cells coupled efficiently to phosphoinositide hydrolysis and mobilization of intracellular Ca2+, and transduced mitogenic signals assessed by [3H]thymidine incorporation in a dose-dependent manner. Moreover, CCK-8 or gastrin I alone promoted the cell growth in serum-free medium. CCK-8 induced tyrosine phosphorylation of several protein species. Among them, mitogen-activated protein (MAP) kinase was tyrosine phosphorylated and activated in response to CCK-8, as was induced by platelet-derived growth factor (PDGF). In contrast, tyrosine phosphorylation of p125FAK (focal adhesion kinase) was induced by CCK-8 but not by PDGF. CCK-8 as well as gastrin I induced the expression of early responsive genes such as c-fos and c-myc. These results suggest that CCK-B/gastrin receptors might transmit mitogenic signals by cross-talking with the tyrosine kinase cascades.
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PMID:Cholecystokinin-B/gastrin receptor signaling pathway involves tyrosine phosphorylations of p125FAK and p42MAP. 810 29

The effects of subchronic (30 days) drinking water exposure of rats to ZnSO4 or Pb(CH3COO)2 alone or in combination on the adrenergically-mediated contractile responses of isolated vas deferens were studied. The contractile effects of the alpha 1, alpha 2-adrenoceptor agonist noradrenaline (NA) and to the alpha 1-adrenoceptor agonist 1-phenylephrine (1-PhE) were decreased after zinc exposure, whereas after lead exposure or lead plus zinc exposure they were not changed. The contractile responses to field electrical stimulation (FES, 0.1 Hz, 1 msec, 80 V) were diminished in amplitude in all metal-treated preparations as compared to controls. The yohimbine-induced restoration of the clonidine inhibited contractions in response to FES was decreased in both lead- and zinc-treated preparations, the EC50 for yohimbine being 0.018 +/- 0.001 microM in control preparations, 0.073 +/- 0.019 microM in lead-treated preparations and 0.056 +/- 0.021 microM in zinc-treated preparations. The calcium-channel blocker verapamil was found to inhibit at low concentrations and to increase at higher concentrations the FES-induced contractile responses in preparations from zinc-exposed rats. The inhibitory effect of cumulatively applied nitrendipine on the FES-induced contractions was increased in both lead- and zinc-treated smooth muscles, but was not altered in the preparations from lead plus zinc-treated rats. Therefore, subchronic exposure to subtoxic doses of lead of zinc led to different changes in the adrenergically-mediated contractility of isolated vas deferens. The changes induced by zinc exposure were not observed after lead plus zinc exposure. All these findings might be of pharmacological, toxicological or clinical importance.
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PMID:Effects of subchronic exposure of rats to lead or zinc on alpha-adrenoceptor-mediated contractile responses in isolated vas deferens. 820 81

The integrin family of heterodimeric cell surface receptors play critical roles in multiple biological processes by mediating cellular adhesion to the extracellular matrix (ECM). Adhesion triggers intracellular signaling cascades, including tyrosine phosphorylation and elevation of [Ca2+]i. The Focal Adhesion Kinase (FAK or pp125FAK), a protein tyrosine kinase that colocalizes with integrins in cellular focal adhesions, is a prime candidate for a mediator of integrin signaling events. Here we report an analysis of the domain structure of FAK in which we have identified a contiguous stretch of 159 amino acids within the COOH terminus essential for correct subcellular localization. When placed in the context of an unrelated cytosolic protein, this Focal Adhesion Targeting (FAT) sequence functions to efficiently mediate the focal adhesion localization of this fusion protein. Furthermore, this analysis suggests that pp125FAK cannot be activated oncogenically by mutation. This result could be explained if pp125FK either exhibits a narrow substrate specificity or is diametrically opposed by cellular phosphatases or other cellular processes.
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PMID:Identification of sequences required for the efficient localization of the focal adhesion kinase, pp125FAK, to cellular focal adhesions. 822 54

Activation of protein kinase C (PKC) in quiescent Swiss 3T3 cells using either the tumor promoter phorbol 12,13-dibutyrate (PDB) or diacylglycerols increased the tyrosine phosphorylation of p125 focal adhesion kinase (p125FAK) by 3.8-fold. PDB stimulation of p125FAK tyrosine phosphorylation was detected within 1 min and reached a maximum within 5 min, considerably slower than PDB stimulation of 80K/MARCKS phosphorylation which was maximal within 1 min. In sharp contrast, bombesin-induced tyrosine phosphorylation of p125FAK reached a maximum (8-fold stimulation) within 1 min after addition of the peptide and occurred with a half-maximal effect of 0.08 nM, 6-fold lower than the half-maximal effect of bombesin on 80K/MARCKS phosphorylation. Down-regulation of PKC by prolonged treatment with PDB blocked the effect of PDB on p125FAK tyrosine phosphorylation but had no effect on the response to bombesin. A selective inhibitor of PKC, GF 109203X, markedly inhibited the stimulation of p125FAK tyrosine phosphorylation by PDB but had little effect on the response to bombesin, vasopressin, and endothelin. Bombesin stimulation of tyrosine phosphorylation could also be dissociated from mobilization of Ca2+ from intracellular stores. Depletion of the intracellular Ca2+ pool by treatment with the tumor promoter thapsigargin completely blocked the ability of bombesin to transiently increase the cytosolic Ca2+ concentration but had no effect on bombesin stimulation of p125FAK tyrosine phosphorylation. In contrast, cytochalasin D, an agent which selectively disrupts the network of actin microfilaments, completely inhibited bombesin- and PDB-induced p125FAK tyrosine phosphorylation. Within the same concentration range (0.3-2 microM), the drug had no effect on other early events stimulated by bombesin, including Ca2+ mobilization and activation of PKC. These findings demonstrate that neither the PKC nor Ca2+ pathways are responsible for the rapid stimulation of p125FAK tyrosine phosphorylation by neuropeptide growth factors. Furthermore, the integrity of the actin cytoskeleton is essential for the effects of both PDB and bombesin.
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PMID:Bombesin stimulation of p125 focal adhesion kinase tyrosine phosphorylation. Role of protein kinase C, Ca2+ mobilization, and the actin cytoskeleton. 831 89

We have investigated the effect that some products of protein catabolism have on endothelium-dependent and -independent relaxation of rabbit aorta rings precontracted with phenylephrine (PE). All the products tested, i.e., creatinine (CRT), guanidinosuccinic acid (GSA), urea (UR), guanidine (GND) and methylguanidine (MG), are structurally related to L-arginine (L-ARG), the substrate for nitric oxide (NO) biosynthesis which accounts for the biological properties of endothelium-derived relaxing factor (EDRF). Endothelium-derived NO (EDNO) release was induced by agents acting via a receptor- [acetylcholine (ACh)] or a nonreceptor-mediated mechanism (calcium ionophore A23187), and the endothelial-independent relaxation was induced by the NO donor glyceryl trinitrate (GTN). CRT (0.1-10 mM) did not modify the endothelium-dependent relaxation caused by ACh or A23187 but produced a small increase in the response to the endothelium-independent vasorelaxant GTN. Concentrations of GSA up to 1 mM did not affect the relaxation of rabbit aortic rings induced by either ACh or A23187, but at 10 mM, GSA enhanced the relaxation produced by these agents. UR (1-100 mM) inhibited, in a concentration-dependent manner, the relaxation induced by ACh, but not that caused by A23187 or GTN. By comparison, GND and MG (0.1-10 mM) produced a concentration-related inhibition of both ACh- and A23187-induced relaxation. The inhibition by these compounds was either completely or partially reversed by L-ARG. In contrast, the relaxation induced by GTN was inhibited only by higher concentrations (10 mM) of GND or MG. These results indicate that some products of protein catabolism can reduce EDNO formation in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of some products of protein catabolism on the endothelium-dependent and -independent relaxation of rabbit thoracic aorta rings. 835 96

We evaluated a new analyzer designed for point-of-care testing of blood gases, sodium, potassium, ionized calcium, and hematocrit. The Gem Premier (Mallinckrodt) system has two components: the analyzer and a disposable cartridge. Analysis takes place in the cartridge, which contains the electrochemical sensors, the calibrants, the reagents, the sampling stylus, and the waste container. The system was evaluated for imprecision and accuracy. With aqueous control materials, total imprecision (CV) was: pH, 0.10-0.18%; PCO2, 3.16-5.78%; PO2, 2.92-4.85%; sodium, 0.82-1.44%; potassium, 1.35-1.48%; ionized calcium, 0.75-1.45%; and hematocrit, 1.13-1.83%. Accuracy of the system was assessed by split-sample comparison with the Radiometer ABL 330 blood gas analyzer for pH and blood gases, the Nova Stat Profile 5 for whole-blood electrolyte and hematocrit analysis, and the IL Phoenix for plasma electrolyte analysis. After outlier correction, regression statistics were excellent for all analytes except sodium, which demonstrated Sy[x values between 1.80 and 2.30 mmol/L and 0.85 < or = r < 0.90.
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PMID:Performance of Gem Premier blood gas/electrolyte analyzer evaluated. 837 66

Platelet adhesion to immobilized fibrinogen stimulates the induction of tyrosine phosphorylation of multiple proteins. However, platelet spreading and tyrosine phosphorylation of three proteins, the focal adhesion kinase pp125FAK and proteins of 101 and 105 kD (pp101 and pp105), require a second adenosine diphosphate (ADP)-dependent costimulatory event. In this study we show that protein kinase C (PKC) inhibitors prevented the induction of tyrosine phosphorylation of pp125FAK, pp101 and pp105, and abolished spreading. These inhibitory effects were not observed after treatment of the platelets with the intracellular Ca2+ chelator BAPTA-AM. This suggested that in platelets, PKC regulates spreading and related protein tyrosine phosphorylation. In addition, the inhibitory effects of apyrase, an ADP scavenger, on spreading and tyrosine phosphorylation of pp125FAK, pp101, and pp105, were not observed in the presence of phorbol 12-myristate 13-acetate (PMA). These data implied that in fibrinogen-adherent platelets integrin ligation and an agonist receptor occupancy are required for the functional association of PKC and the alpha IIb beta 3-mediated signaling pathways. Taken together these results show that PKC plays a central role in the transduction of intracellular signals downstream from alpha IIb beta 3 that regulate spreading and pp125FAK phosphorylation.
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PMID:Protein kinase C regulates tyrosine phosphorylation of pp125FAK in platelets adherent to fibrinogen. 854 37


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