Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cellular isoform of prion protein (PrP(C)) is a cell-surface glycosyl-phosphatidylinositol-anchored protein which is ubiquitously expressed on the cell membrane. It may function as a cell receptor or as a cell adhesion molecule. Thyroid follicles, obtained from patients with Graves' disease at thyroidectomy, were cultured in F-12/RPMI-1640 medium supplemented with 0.5% fetal bovine serum and bovine thyroid stimulating hormone (bTSH). Northern blot analyses revealed that bTSH increased the steady-state expression levels of PrP mRNA in a time- and dose-dependent manner. This increase was reproduced by dibutyryl-cAMP and 12-decanoylphorbol-13-acetate. The mRNA expression was greater in thyroid follicles in suspension culture than in thyrocytes cultured in a monolayer. These findings suggest that TSH stimulates PrP mRNA expression in thyrocytes through the protein kinase A and C pathways. The greater mRNA expression in thyroid follicles than in monolayer cells suggests that PrP(C) may be involved in structure formation or maintenance of thyroid follicles.
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PMID:Stimulation of cellular prion protein expression by TSH in human thyrocytes. 1276 34

Individuals affected with tuberous sclerosis complex (TSC) develop cortical tubers characterized by disorganized cytoarchitecture and morphologically abnormal cell types, such as dysplastic neurons (DNs) and giant cells (GCs). As part of ongoing cDNA array analysis to study the molecular pathogenesis of tuber formation, we detected increased expression of intercellular adhesion molecule-1 (ICAM-1) mRNA, a cell adhesion molecule (CAM) that functions in cytokine signaling, in tubers. Western and immunohistochemical analyses revealed that ICAM-1 protein was selectively expressed in tubers, but was only minimally expressed in control cortex, adjacent nontuberal cortex, or in non-TSC focal cortical dysplasia. Increased expression of ICAM-1 was found in mice in which the Tsc1 gene was conditionally inactivated in astrocytes. Expression of molecules involved in ICAM-1 activation and cytokine signaling were increased in tubers, including tumor necrosis factor alpha (TNF-alpha), mitogen activated protein kinase (MAPK), and nuclear factor kappa B (NF-kappaB). Numerous CD68-immunoreactive macrophages were observed clustered around GCs further supporting an inflammatory response in tubers. Expression of caspase 8 and Fas support cytokine activation and detection of TUNEL reactivity suggests ongoing cell death in tubers. Specific alterations in ICAM-1, TNF-alpha, NF-kappaB1, and MAPK expression coupled with the detection of numerous CD68-immunoreactive macrophages suggests activation of proinflammatory cytokine signaling pathways in tubers that may culminate in cell death.
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PMID:Expression of ICAM-1, TNF-alpha, NF kappa B, and MAP kinase in tubers of the tuberous sclerosis complex. 1457 49

Axonal growth cones migrate along the correct paths during development, not only directed by guidance cues but also contacted by local environment via cell adhesion molecules (CAMs). Asymmetric Ca2+ elevations in the growth cone cytosol induce both attractive and repulsive turning in response to the guidance cues (Zheng, J.Q. 2000. Nature. 403:89-93; Henley, J.R., K.H. Huang, D. Wang, and M.M. Poo. 2004. Neuron. 44:909-916). Here, we show that CAMs regulate the activity of ryanodine receptor type 3 (RyR3) via cAMP and protein kinase A in dorsal root ganglion neurons. The activated RyR3 mediates Ca2+-induced Ca2+ release (CICR) into the cytosol, leading to attractive turning of the growth cone. In contrast, the growth cone exhibits repulsion when Ca2+ signals are not accompanied by RyR3-mediated CICR. We also propose that the source of Ca2+ influx, rather than its amplitude or the baseline Ca2+ level, is the primary determinant of the turning direction. In this way, axon-guiding and CAM-derived signals are integrated by RyR3, which serves as a key regulator of growth cone navigation.
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PMID:Cell adhesion molecules regulate Ca2+-mediated steering of growth cones via cyclic AMP and ryanodine receptor type 3. 1617 6

Extracellular ATP exerts both short-term and long-term effects in the CNS by stimulating cell-surface purinergic receptors. Here we have examined the effect of purinergic receptor activation on N-cadherin expression, a calcium-dependent cell adhesion molecule involved in many processes, including glia-glia and axon-glia interactions. When primary cultures of rat cortical astrocytes were treated with ATP, N-cadherin protein expression increased in a time- and concentration-dependent manner. In addition, ATP treatment caused an increase in N-cadherin immunoreactivity in both the cytoplasm and on the cell surface membrane. Interestingly, experiments with cycloheximide revealed that relocalization of N-cadherin to the cell surface membrane were independent of protein synthesis. The ATP-induced increase in N-cadherin protein expression was blocked by reactive blue 2 and 8-(p-sulfophenyl)-theophylline, suggesting involvement of both P2 and P1 purinergic receptors, respectively. In addition, N-cadherin expression was partially blocked when signaling from purinergic receptors to extracellular signal regulated protein kinase or Akt was inhibited by 1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene or wortmannin, respectively. By using an in vitro model of traumatic CNS injury, we found that N-cadherin expression was increased when astrocytes were subjected to rapid and reversible mechanical strain. The findings presented here demonstrate a role for extracellular ATP, purinergic receptors and protein kinase signaling in regulating N-cadherin expression and suggest a role for this mechanism in cell-cell interactions.
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PMID:Purinergic receptor signaling regulates N-cadherin expression in primary astrocyte cultures. 1818 57

Uptake of oxidized LDL (ox-LDL) by vascular endothelial cells is a critical step in the initiation and development of atherosclerosis. Adhesion molecules are upregulated by ox-LDL and numerous inflammatory cytokines and play a pivotal role in atherogenesis. In this study, we examined whether diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS), 3 major organosulfur compounds of garlic oil, reduce adhesion molecule expression induced by ox-LDL and, if so, through what mechanism. Human umbilical vein endothelial cells were preincubated with 1 mmol/L DAS, 200 mumol/L DADS, or 100 mumol/L DATS for 16 h and then with 40 mg/L ox-LDL for an additional 24 h. ox-LDL induction of cellular and cell surface expression of E-selectin and vascular cell adhesion molecule (VCAM)-1 was suppressed by garlic allyl sulfides in the order DATS > DADS > DAS. The adhesion of HL-60 cells to endothelial cells was inhibited 27 and 33% and the production of cellular peroxides was inhibited 43 and 50% by DADS and DATS, respectively (P < 0.05). ox-LDL alone dephosphorylated protein kinase B (PKB) and cAMP responsive element binding protein (CREB); such deactivation was reversed by DADS and DATS. Electrophoretic mobility shift assay showed that the activation of CREB binding to DNA was consistent with changes in CREB phosphorylation. The protein kinase A (PKA) inhibitor H89 reversed the suppression of VCAM-1 by DADS and DATS, but the phosphoinositide 3-kinase (PI3K) inhibitor wortmannin had no effect. In contrast, wortmannin abolished DADS- and DATS-induced suppression of ox-LDL-induced E-selectin expression. These results suggest that the suppression of ox-LDL-induced E-selectin and VCAM-1 expression by DADS and DATS and, thus, monocyte adhesion to endothelial cells is likely dependent on the PI3K/PKB or PKA/CREB signaling pathway in an adhesion molecule-specific manner. To our knowledge, this is the first report that garlic modulates ox-LDL-mediated leukocyte adhesion to human endothelial cells through the PKB and PKA pathways.
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PMID:Diallyl disulfide and diallyl trisulfide suppress oxidized LDL-induced vascular cell adhesion molecule and E-selectin expression through protein kinase A- and B-dependent signaling pathways. 1849 25

Receptor protein tyrosine phosphatase alpha (RPTPalpha) phosphatase activity is required for intracellular signaling cascades that are activated in motile cells and growing neurites. Little is known, however, about mechanisms that coordinate RPTPalpha activity with cell behavior. We show that clustering of neural cell adhesion molecule (NCAM) at the cell surface is coupled to an increase in serine phosphorylation and phosphatase activity of RPTPalpha. NCAM associates with T- and L-type voltage-dependent Ca(2+) channels, and NCAM clustering at the cell surface results in Ca(2+) influx via these channels and activation of NCAM-associated calmodulin-dependent protein kinase IIalpha (CaMKIIalpha). Clustering of NCAM promotes its redistribution to lipid rafts and the formation of a NCAM-RPTPalpha-CaMKIIalpha complex, resulting in serine phosphorylation of RPTPalpha by CaMKIIalpha. Overexpression of RPTPalpha with mutated Ser180 and Ser204 interferes with NCAM-induced neurite outgrowth, which indicates that neurite extension depends on NCAM-induced up-regulation of RPTPalpha activity. Thus, we reveal a novel function for a cell adhesion molecule in coordination of cell behavior with intracellular phosphatase activity.
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PMID:NCAM induces CaMKIIalpha-mediated RPTPalpha phosphorylation to enhance its catalytic activity and neurite outgrowth. 1880 27

The neurofibromatosis-2 (NF2) tumor suppressor protein, merlin or schwannomin, inhibits cell proliferation by modulating the growth activities of its binding partners, including the cell surface glycoprotein CD44, membrane-cytoskeleton linker protein ezrin and PIKE (PI 3-kinase enhancer) GTPase, etc. Merlin exerts its growth suppressive activity through a folded conformation that is tightly controlled through phosphorylation by numerous protein kinases including PAK, PKA and Akt. Merlin inhibits PI 3-kinase activity through binding to PIKE-L. Now, we show that merlin is a physiological substrate of Akt, which phosphorylates merlin on both T230 and S315 residues. This phosphorylation abolishes the folded conformation of merlin and inhibits its association with PIKE-L, provoking merlin polyubiquitination and proteasome-mediated degradation. This finding demonstrates a negative feed-back loop from merlin/PIKE-L/PI 3-kinase to Akt in tumors- The proliferation repressive activity of merlin is also partially regulated by S518 phosphorylation- Thus, Akt-mediated merlin T230/S315 phosphorylation, combined with S518 phosphorylation by PAK and PKA, provides new insight into abrogating merlin function in the absence of merlin mutational inactivation.
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PMID:Phosphorylation of merlin regulates its stability and tumor suppressive activity. 1926 46

Initiation of cell growth and neoplastic transformation frequently involves activation of growth factor receptor-coupled tyrosine kinases and stimulation of the phosphoinositide second messenger system. Altered expression of CD44 variants was reported in several malignant tumor types with possible implications for tumor progression and prognosis. CD44 variant expression was reported to be associated with second messenger activation and differentiation. We therefore investigated the effects of butyrate-induced short-term differentiation on phosphoinositide signaling, phospholipase C and protein kinase C activity and alteration of CD44 variant expression in human HT-29 colon carcinoma cells. HT-29 cells were cultured with sodium butyrate for 6 days. Phosphoinositide turnover was measured by [32P]orthophosphate incorporation and phospholipase C activity by determination of the release of [3H]inositolphosphates from [3H]myoinositol prelabeled cells. Protein kinase C activity was determined by histone III-S phosphorylation, PKC subtype expression by RNase protection analysis, and CD44 variant expression was determined by RT-PCR using variant-specific primers. Treatment of HT-29 human colon carcinoma cells with sodium butyrate caused a dose-dependent inhibition of cell proliferation (IC50, 2.5 mM) with morphologic signs of an enterocytic differentiation following 6 days of treatment. The phosphoinositide turnover as determined by 32P-incorporation under non-equilibrium conditions showed a 30-40% inhibition of labeled phosphoinositides and phosphatidic acid and a dose-dependent inhibition of cholinergically stimulated phospholipase C activity as a secondary event following butyrate-induced enterocytic differentiation. However, long-term incubation of HT-29 cells with phorbol ester or an inhibitor of classical and novel PKC subtypes did not affect cell proliferation. In butyrate-treated HT-29 cells activation of calcium-dependent protein kinase C by cholinergic stimulation or phorbolester treatment induced an increase in membrane-bound cPKC activity, while expression of distinct high- molecular CD44 variant transcripts v3 (670 bp), v5 (940 bp) and v8 (535 bp) were drastically reduced after butyrate pretreatment. Enterocytic differentiation of HT-29 colon carcinoma cells seems to be associated with alterations in phosphoinositide resynthesis, phospholipase C activity and ligand/receptor-induced PKC translocation. The observed reduction of distinct high-molecular CD44v3, v5 and v8 variants following butyrate-induced differentiation indicates an association of specific CD44 variant expression with the malignant phenotype of HT-29 colon cancer cells, thus being possible targets for new diagnostic and therapeutic strategies.
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PMID:Butyrate-induced alterations of phosphoinositide metabolism, protein kinase C activity and reduced CD44 variant expression in HT-29 colon cancer cells. 1936 Mar 23

Vascular endothelial (VE)-cadherin is a cell-cell adhesion molecule involved in endothelial barrier functions. Previously, we reported that cAMP-Epac-Rap1 signal enhances VE-cadherin-dependent cell adhesion. Here, we further scrutinized how cAMP-Epac-Rap1 pathway promotes stabilization of VE-cadherin at the cell-cell contacts. Forskolin induced circumferential actin bundling and accumulation of VE-cadherin fused with green fluorescence protein (VEC-GFP) on the bundled actin filaments. Fluorescence recovery after photobleaching (FRAP) analyses using VEC-GFP revealed that forskolin stabilizes VE-cadherin at cell-cell contacts. These effects of forskolin were mimicked by an activator for Epac but not by that for protein kinase A. Forskolin-induced both accumulation and stabilization of junctional VEC-GFP was impeded by latrunculin A. VE-cadherin, alpha-catenin, and beta-catenin were dispensable for forskolin-induced circumferential actin bundling, indicating that homophilic VE-cadherin association is not the trigger of actin bundling. Requirement of alpha- and beta-catenins for forskolin-induced stabilization of VE-cadherin on the actin bundles was confirmed by FRAP analyses using VEC-GFP mutants, supporting the classical model that alpha-catenin could potentially link the bundled actin to cadherin. Collectively, circumferential actin bundle formation and subsequent linkage between actin bundles and VE-cadherin through alpha- and beta-catenins are important for the stabilization of VE-cadherin at the cell-cell contacts in cAMP-Epac-Rap1 signal-activated cells.
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PMID:Vascular endothelial-cadherin stabilizes at cell-cell junctions by anchoring to circumferential actin bundles through alpha- and beta-catenins in cyclic AMP-Epac-Rap1 signal-activated endothelial cells. 2003 4

CV-159 is a unique dihydropyridine Ca(2+) antagonist with an anti-calmodulin (CaM) action. A pathogenic feature of atherosclerosis is vascular inflammatory change. In the present study, we examined whether CV-159 exerts protective effects on smooth muscle inflammatory responses. After pretreatment of rat mesenteric arterial smooth muscle cells (SMCs) with CV-159 (0.1 - 10 microM, 30 min), TNF-alpha (10 ng/ml) was applied for 20 min or 24 h. CV-159 inhibited TNF (24 h)-induced vascular cell adhesion molecule (VCAM)-1 as determined by Western blotting. CV-159 inhibited TNF (20 min)-induced phosphorylation of Akt (Ser473) and NF-kappaB p65 (Ser536). An Akt inhibitor, LY294002, and an NF-kappaB inhibitor, pyrrolidine dithiocarbamate, inhibited TNF-induced VCAM-1. An antioxidant drug, N-acetyl-L-cysteine (NAC) inhibited TNF-induced VCAM-1. NAC also inhibited TNF-induced phosphorylation of Akt and NF-kappaB. Furthermore, CV-159 inhibited TNF-induced reactive oxygen species (ROS) production as determined fluorometrically using dichlorodihydrofluorescein diacetate. A CaM inhibitor, W-7, and a calcium/CaM-dependent protein kinase type II inhibitor, KN93, inhibited TNF-induced VCAM-1. W-7 and KN93 inhibited TNF-induced phosphorylation of Akt but not NF-kappaB. The present results indicate that in vascular SMCs, CV-159 inhibits TNF-induced VCAM-1 through inhibition of NF-kappaB and Akt phosphorylation. CV-159 prevents NF-kappaB phosphorylation by inhibiting ROS, while it prevents Akt phosphorylation by inhibiting both ROS and CaM.
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PMID:Mechanisms underlying the anti-inflammatory effects of the Ca2+/calmodulin antagonist CV-159 in cultured vascular smooth muscle cells. 2056 16


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