Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.13 (protein kinase C)
 49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Insulin stimulates glucose transport into muscle and fat cells by enhancing GLUT4 abundance in the plasma membrane through activation of phosphatidylinositol 3-kinase (PI3K). Protein kinase B (PKB) and PKCzeta are known PI3K downstream targets in the regulation of GLUT4. The serum- and glucocorticoid-inducible kinase SGK1 is similarly activated by insulin and capable to regulate cell surface expression of several metabolite transporters. In this study, we evaluated the putative role of SGK1 in the modulation of GLUT4. Coexpression of the kinase along with GLUT4 in Xenopus oocytes stimulated glucose transport. The enhanced GLUT4 activity was paralleled by increased transporter abundance in the plasma membrane. Disruption of the SGK1 phosphorylation site on GLUT4 ((S274A)GLUT4) abrogated the stimulating effect of SGK1. In summary, SGK1 promotes glucose transporter membrane abundance via GLUT4 phosphorylation at Ser274. Thus, SGK1 may contribute to the insulin and GLUT4-dependent regulation of cellular glucose uptake.
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PMID:Role of SGK1 kinase in regulating glucose transport via glucose transporter GLUT4. 1738 6

Leucine-rich repeat C4 (LRRC4) has been shown to inhibit glioma cell proliferation, however, little is known about the mechanism(s) underlying the action of LRRC4. Here, we show that two glioblstoma U251 cell clones stably expressing LRRC4 were established. LRRC4 expression significantly inhibited the expression of some cytokines and their receptors determined by microarray and Western blot assays, and dramatically reduced cytokine-induced AP-1, NF-kB, and CyclinD1 activation in glioma cells. Furthermore, LRRC4 expression in glioma cells significantly downregulated spontaneous and cytokine-induced expression of K-RAS and phosphorylation of c-Raf, ERK, AKT, NF-kBp65, p70S6K, and PKC, suggesting that LRRC4 inhibited receptor tyrosine kinase (RTK) signaling pathways. Moreover, treatment with bFGF, IGF1, or IGF2 stimulated LRRC4(-/-), but not the LRRC4(+), glioma cell proliferation, indicating that LRRC4 mitigated cytokine-stimulated proliferation in glioma cells. In addition, treatment of LRRC4(-/-) glioma cells with EGF, IGF2, or PDGF promoted long distance mobilization, but induced little migration in LRRC4(+) glioma cells, suggesting that LRRC4 retarded cytokine-promoted glioma cell migration in vitro. Finally, human vessel endothelial cells (ECV304) treated with VEGF grew, aligned and formed hollow tube-like structures in vitro. In contrast, LRRC4(+) ECV304 treated with VEGF failed to form vessel-tube structures. Collectively, LRRC4 expression inhibited the expression of some growth factors, cytokines and their receptors, and the capacity of glioma cells responding to cytokine stimulation, leading to inhibition of glioma cell proliferation. Conceivably, induction of LRRC4 expression may provide new intervention for human glioma in the clinic.
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PMID:LRRC4 inhibits glioblastoma cell proliferation, migration, and angiogenesis by downregulating pleiotropic cytokine expression and responses. 1754 39

Genetic factors, Helicobacter pylori infection, salt over-uptake, decreased vegetable/fruit consumption, smoking, and metabolic syndrome are risk factors of human gastric cancer. Germline mutations of CDH1 gene, and SNPs of PTPN11 (SHP2), TLR4, IL1B, TNFA, BMP6, GDF15 and RUNX3 genes are associated with gastric cancer. Helicobacter pylori activates CagA-SHP2-ERK and peptidoglycan-NOD1-NFkappaB signaling cascades in gastric epithelial cells using type IV secretion system, and also TRAF6-MAP3K7-NFkappaB and TRAF6-MAP3K7-AP-1 signaling cascades in epithelial and immune cells through lipopolysaccharide recognition by TLR2 or TLR4. IL-1beta, IL-6, IL-8, TNFalpha and IFNgamma are elevated in gastric mucosa with Helicobacter pylori infection. IL-6 and TNFalpha induce upregulation of WNT5A and WNT10B, respectively. WNT signals are transduced to beta-catenin-TCF/LEF, RhoA, JNK, PKC, NFAT, and NLK signaling cascades. WNT-beta-catenin-TCF/LEF signaling induces upregulation of MYC, CCND1, WISP1, FGF20, JAG1 and DKK1 genes. Notch signals are transduced to CSL-NICD-MAML and NFkappaB signaling cascades. FGF signals are transduced to ERK, PI3K-AKT, PKC, and NFAT signaling cascades. Helicobacter pylori infection induces SHH upregulation in parietal cell lineage, while BMP signals induce IHH upregulation in pit cell lineage. Hedgehog signals induce upregulation of GLI1, PTCH1, CCND2, FOXL1, JAG2 and SFRP1 genes. JAG1 and JAG2 activate Notch signaling, while DKK1 and SFRP1 inhibit WNT signaling. Stem cell signaling network, consisting of WNT, Notch, FGF, Hedgehog and BMP signaling pathways, is activated during chronic Helicobacter pylori infection. Epigenetic silencing of SFRP1 gene occurs in the earlier stage of carcinogenesis in the stomach, while amplification and overexpression of FGFR2 gene in the later stage. Dysregulation of the stem cell signaling network due to the accumulation of germline mutation, SNP, Helicobacter pylori infection, epigenetic change and genetic alteration gives rise to gastric cancer. SNP typing and custom-made microarray analyses on genes encoding stem cell signaling molecules could be utilized for the personalized medicine.
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PMID:Dysregulation of stem cell signaling network due to germline mutation, SNP, Helicobacter pylori infection, epigenetic change and genetic alteration in gastric cancer. 1756 83

The c-MET receptor can be overexpressed, amplified, or mutated in solid tumours including small cell lung cancer (SCLC). In c-MET-overexpressing SCLC cell line NCI-H69, hepatocyte growth factor (HGF) dramatically induced c-MET phosphorylation at phosphoepitopes pY1230/1234/1235 (catalytic tyrosine kinase), pY1003 (juxtamembrane), and also of paxillin at pY31 (CRKL-binding site). We utilised a global proteomics phosphoantibody array approach to identify further c-MET/HGF signal transduction intermediates in SCLC. Strong HGF induction of specific phosphorylation sites in phosphoproteins involved in c-MET/HGF signal transduction was detected, namely adducin-alpha [S724], adducin-gamma [S662], CREB [S133], ERK1 [T185/Y187], ERK1/2 [T202/Y204], ERK2 [T185/Y187], MAPKK (MEK) 1/2 [S221/S225], MAPKK (MEK) 3/6 [S189/S207], RB [S612], RB1 [S780], JNK [T183/Y185], STAT3 [S727], focal adhesion kinase (FAK) [Y576/S722/S910], p38alpha-MAPK [T180/Y182], and AKT1[S473] and [T308]. Conversely, inhibition of phosphorylation by HGF in protein kinase C (PKC), protein kinase R (PKR), and also CDK1 was identified. Phosphoantibody-based immunohistochemical analysis of SCLC tumour tissue and microarray established the role of c-MET in SCLC biology. This supports a role of c-MET activation in tumour invasive front in the tumour progression and invasion involving FAK and AKT downstream. The c-MET serves as an attractive therapeutic target in SCLC, as shown through small interfering RNA (siRNA) and selective prototype c-MET inhibitor SU11274, inhibiting the phosphorylation of c-MET itself and its downstream molecules such as AKT, S6 kinase, and ERK1/2. Investigation of mechanisms of invasion and, ultimately, metastasis in SCLC would be very useful with these signal transduction molecules.
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PMID:Downstream signalling and specific inhibition of c-MET/HGF pathway in small cell lung cancer: implications for tumour invasion. 1766 9

Enzastaurin, an oral serine/threonine kinase inhibitor, suppresses signaling through protein kinase C (PKC)-beta and the phosphatidylinositol 3-kinase/AKT pathway to induce tumor cell apoptosis, reduce proliferation, and suppress tumor-induced angiogenesis. In contrast to previous PKC inhibitors, enzastaurin is very well tolerated with a favorable safety profile, allowing it to be dosed for extended durations. In the present review, we summarize the rationale for targeting PKC in cancer, the preclinical experience of enzastaurin, and the clinical findings of the current phase I and II studies. Based on the combined information, we present the rationale for its future assessment in the treatment of lung cancer.
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PMID:Enzastaurin, a protein kinase Cbeta- selective inhibitor, and its potential application as an anticancer agent in lung cancer. 1767 Nov 57

Calcium is a second messenger for many signaling pathways in B cells, but its role as a receptor ligand has not been well characterized. However, pulses of free calcium were found to cause the rapid release of internal calcium stores in normal human B cells. This response appeared to be mediated by a cell surface protein with receptor properties as it could be blocked by pretreatment with trypsin and with kinase and phospholipase Cgamma inhibitors. The calcium receptor on B cells was not the conventional calcium-sensing receptor (CaSR) since B cells did not express CaSR and calcium-induced responses could not be blocked by specific CaSR inhibitors. B-cell responses to extracellular calcium activated phosphoinositide-3 kinase/AKT, calcineurin, extracellular signal regulated kinase, p38 mitogen-activated protein kinase, protein kinase C, Ca(2+)/calmodulin kinase II, and nuclear factor-kappaB signaling pathways, and resulted in transcription of the early response gene, CD83. This extracellular calcium sensor enhanced B-cell responses to Toll-like receptor, B-cell receptor, and cytokine receptor agonists. These findings suggest a means by which B cells prepare to engage in immune responses by responding to calcium fluctuations in their environment.
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PMID:Extracellular calcium sensing promotes human B-cell activation and function. 1772 42

Chemotaxis plays an important role in metastasis of cancer cells. In the current study, we investigated the role of PTEN, a tumor suppressor, in chemotaxis of human breast cancer cells. Over-expression of PTEN inhibited EGF-induced chemotaxis, probably due to an overall reduction of PIP(3) levels. Disruption of PTEN by siRNA caused a marked decrease in chemokinesis, cell adhesion, and membrane spreading, resulting in a severe defect in chemotaxis. In PTEN disrupted cells, PDK1, AKT, and PKCzeta exhibited elevated basal activities, which prevented EGF-induced further activation of these molecules. In the absence of EGF, active PDK1 was detected on multiple directions of the plasma membranes of PTEN disrupted cells, which competed against EGF-induced gradient sensing. To confirm the biological relevance of in vitro studies, both PTEN disrupted cells and its parental human breast cancer cells were injected into tail veins of SCID mice. Mice injected with PTEN disrupted cancer cells showed a marked decrease in lung metastasis. Taken together, our data show that PTEN plays a non-redundant role in EGF-induced chemotaxis of human breast cancer cells, and an optimal level of PTEN is required in these responses.
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PMID:Investigate the role of PTEN in chemotaxis of human breast cancer cells. 1776

Growth factor receptor-bound protein-7 (GRB-7), an adaptor molecule, can interact with multiple signal transduction molecules. GRB-7 is amplified concurrently with HER-2/Neu in most, if not all, of breast cancer with chromosome 17q11-21 amplification. GRB-7 gene amplification is associated with RNA over-expression. We show GRB-7 protein is over-expressed by immunoblotting in breast cancer cell lines and primary breast tumors with HER-2/Neu protein over-expression. Over-expression of GRB-7 in MCF-7 breast cancer cells that over-express HER-2/Neu leads to activation of tyrosine phosphorylation of HER-2/Neu. Knockdown of GRB-7 expression in SKBR-3 breast cancer cells with naturally occurring HER-2/Neu gene amplification decreases tyrosine phosphorylation of HER-2/Neu. Activation of HER-2/Neu phosphorylation is associated with increase in tyrosine phosphorylation of phosphoinositide-specific lipase C-gamma-1 (PLC-gamma-1) and recruitment of PLC-gamma-1 to HER-2/Neu protein molecule. Activation of downstream protein kinase C (PKC) pathway is evidenced by increase in the phosphorylation of a common PKC substrate-myristoylated alanine-rich protein kinase C substrate (MARCKS). In addition, over-expression of GRB-7 in MCF-7 breast cancer cells that over-express HER-2/Neu leads to activation of AKT phosphorylation. Knockdown of GRB-7 expression in MB-453 and SKBR-3 breast cancer cells results in decrease in AKT phosphorylation. GRB-7 over-expression therefore facilitates activation of phosphorylation of HER-2/Neu and AKT in breast cancer cells with HER-2/Neu over-expression. GRB-7 over-expression in MCF-7 cells over-expressing HER-2/Neu leads to morphologic change of cells and promotes tumor xenograft growth in nude mice. GRB-7 over-expression therefore plays pivotal roles in activating signal transduction and promoting tumor growth in breast cancer cells with chromosome 17q11-21 amplification.
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PMID:GRB-7 facilitates HER-2/Neu-mediated signal transduction and tumor formation. 1791 6

Na/H exchange regulatory factor 1 (NHERF1) is a scaffolding protein that regulates signaling and trafficking of several G protein-coupled receptors (GPCRs), including the parathyroid hormone receptor (PTH1R). GPCRs activate extracellular signal-regulated kinase (ERK)1/2 through different mechanisms. Here, we characterized NHERF1 regulation of PTH1R-stimulated ERK1/2. Parathyroid hormone (PTH) stimulated ERK1/2 phosphorylation by a protein kinase A (PKA)-dependent, but protein kinase C-, cyclic adenosine 5'-monophosphate-, and Rap1-independent pathway in Chinese hamster ovary cells stably transfected with the PTH1R and engineered to express NHERF1 under the control of tetracycline. NHERF1 blocked PTH-induced ERK1/2 phosphorylation downstream of PKA. This suggested that NHERF1 inhibitory effects on ERK1/2 occur at a postreceptor locus. Forskolin activated ERK1/2, and this effect was blocked by NHERF1. NHERF1 interacted with AKT and inhibited ERK1/2 activation by decreasing the stimulatory effect of 14-3-3 binding to B-Raf, while increasing the inhibitory influence of AKT negative regulation on ERK1/2 activation. This novel regulatory mechanism provides a new model by which cytoplasmic adapter proteins modulate ERK1/2 activation through a receptor-independent mechanism involving B-Raf.
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PMID:Na/H exchange regulatory factor 1, a novel AKT-associating protein, regulates extracellular signal-regulated kinase signaling through a B-Raf-mediated pathway. 1827 83

We have reported that Erbin expression was down-regulated in the Jurkat leukaemia T lymphocytes treated with the recombinant soluble tumour necrosis factor-related apoptosis-inducing ligand (rsTRAIL). Herein, we studied the expression and the regulation of Erbin and its binding partner, ErbB2, in the MCF-7 breast cancer cell line. We showed that the expressions of Erbin and ErbB2 were modulated by PKCdelta inhibitor, rottlerin, in the TRAIL-resistant MCF-7 cell line. The affinity of Erbin-ErbB2 interaction was reduced by ErbB2 phosphorylation. Inhibiting the expression of Erbin facilitated the sensitivity of the MCF-7 cells to TRAIL via suppressing the ErbB2/AKT/NF-kappaB signalling pathway.
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PMID:Erbin-regulated sensitivity of MCF-7 breast cancer cells to TRAIL via ErbB2/AKT/NF-kappaB pathway. 1831 30


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