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)

Vitamin A and its metabolite retinoic acid (RA) are essential elements for normal lung development and the differentiation of lung epithelial cells. We previously showed that RA rapidly activated cyclic AMP response element-binding protein (CREB) in a nonclassical manner in normal human tracheobronchial epithelial (NHTBE) cells. In the present study, we further demonstrated that this nonclassical signaling of RA on the activation of CREB plays a critical role in regulating the expression of airway epithelial cell differentiation markers, the MUC2, MUC5AC, and MUC5B genes. We found that RA rapidly activates the protein kinase Calpha isozyme and transmits the activation signal to CREB via the Raf/MEK/extracellular signal-regulated kinase/p90 ribosomal S6 kinase (RSK) pathway. Activated RSK translocated from the cytoplasm to the nucleus, where it phosphorylates CREB. Activated CREB then binds to a cis-acting replication element motif on the promoter (at nucleotides [nt] -878 to -871) of the MUC5AC gene. The depletion of CREB using small interfering RNA abolished not only the RA-induced MUC5AC but also RA-induced MUC2 and MUC5B. Taken together, our findings demonstrate that CREB activation via this nonclassical RA signaling pathway may play an important role in regulating the expression of mucin genes and mediating the early biological effects of RA during normal mucous differentiation in NHTBE cells.
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PMID:Regulation of mucin gene expression by CREB via a nonclassical retinoic acid signaling pathway. 1764 88

To investigate the pathobiological behaviors of gastric mixed-type (MT) carcinomas and gastric carcinogenesis, the clinicopathological characteristics of MT carcinomas were analyzed and compared with intestinal-type (IT) and diffuse-type (DT) carcinomas. The expression of Ki-67, caspase-3, p53, fragile histine triad (FHIT), maspin, extracellular matrix metalloproteinase inducer (EMMPRIN), vascular growth factor (VEGF), MUC-2, 4, 5AC and 6, CD44, E-cadherin, beta-catenin, and phosphorylated glycogen synthase kinase 3beta-ser9 (P-GSK3beta-ser9) was examined on tissue microarrays using immunohistochemistry. It was found that MT carcinomas exhibited large size, deep invasion, frequent local invasion, and lymph node metastasis in comparison with IT and DT carcinomas (p < 0.05). All the markers except MUC-5AC showed higher expression in IT than DT carcinomas (p < 0.05). The expression of maspin, EMMPRIN, VEGF, MUC-4, and membrane E-cadherin was stronger in MT intestinal than diffuse component (p < 0.05). Immunoreactivities to Ki-67, EMMPRIN, and VEGF were weaker in IT carcinoma than in the MT intestinal portion (p < 0.05), while the opposite was true for CD44, MUC-2, and MUC-6 (p < 0.05). The MT diffuse component displayed a higher expression of FHIT, VEGF, and P-GSK3beta-ser9 than DT carcinoma (p < 0.05). The accumulative survival rate of the IT carcinoma patients was higher than the other types (p < 0.05). The invasive depth, venous invasion, lymph node, peritoneal or liver metastasis, and Lauren's classification were independent prognostic factors for gastric carcinomas (p < 0.05). These findings suggested that MT carcinomas were also indicated to be more aggressive than IT and DT carcinomas. Significant differences were observed in the proliferation, apoptosis, angiogenesis, mucin secretion, and cell adhesion between IT and DT carcinomas, whereas only a few of these characteristics showed differences between the MT intestinal and diffuse parts, thus suggesting that both the MT components might originate from the stem cells with similar genetic traits, but follow different histogenic pathways.
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PMID:Mixed-type gastric carcinomas exhibit more aggressive features and indicate the histogenesis of carcinomas. 1826 6

Sorogena stoianovitchae is the only ciliate that undergoes fruiting body development. Previously, we demonstrated that the developmental process is divided into five distinct stages: aggregation, compact aggregation, secretion of a mucous matrix, stalk elongation, and completion of the fruiting body. When S. stoianovitchae is mildly starved, several hundreds of cells aggregate beneath the water surface, and the aggregate develops into an aerial fruiting body. Essential requirements for fruiting body development are high-cell density, a light-dark cycle, and a dark period of more than 8 consecutive hours. In addition, the initial aggregation begins during the night, and light stimulation at sunrise triggers subsequent development. To elucidate the genes involved in fruiting body development, we carried out a reverse transcription-polymerase chain reaction (RT-PCR) in cells before and after such development. Thirty-six sequences with stage-specific expression patterns were cloned and partially sequenced. BLASTX search revealed that sequences with high identity for extracellular proteins (mucin, proteophosphoglycan) or membrane proteins (surface protein, TM9SF) are likely candidates for aggregation material, mucous matrix, and stalk material. Other sequences showed similarities to proteins, such as the casein kinase related to exocytosis in Paramecium, suggesting that they are involved in exocytosis signaling pathways for fruiting body development.
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PMID:Differentially expressed genes during fruiting body development in the aggregative ciliate Sorogena stoianovitchae (Ciliophora: Colpodea). 1831 64

Protease-activated receptor-2 (PAR-2) is activated when trypsin cleaves its NH(2) terminus to expose a tethered ligand. We previously demonstrated that PAR-2 activates ion channels in pancreatic duct epithelial cells (PDEC). Using real-time optical fluorescent probes, cyan fluorescence protein-Epac1-yellow fluorescence protein for cAMP, PH(PLC-delta1)-enhanced green fluorescent protein for phosphatidylinositol 4,5-bisphosphate, and protein kinase Cgamma (PKCgamma)-C1-yellow fluorescence protein for diacylglycerol, we now define the signaling pathways mediating PAR-2 effect in dog PDEC. Although PAR-2 activation does not stimulate a cAMP increase, it induces phospholipase C to hydrolyze phosphatidylinositol 4,5-bisphosphate into inositol 1,4,5-trisphosphate and diacylglycerol. Intracellular Ca(2+) mobilization from inositol 1,4,5-trisphosphate-sensitive Ca(2+) stores and a subsequent Ca(2+) influx through store-operated Ca(2+) channels cause a biphasic increase in intracellular Ca(2+) concentration ([Ca(2+)](i)), measured with Indo-1 dye. Single-cell amperometry demonstrated that this increase in [Ca(2+)](i) in turn causes a biphasic increase in exocytosis. A protein kinase assay revealed that trypsin also activates PKC isozymes to stimulate additional exocytosis. Paralleling the increased exocytosis, mucin secretion from PDEC was also induced by trypsin or the PAR-2 activating peptide. Consistent with the serosal localization of PAR-2, 1 microm luminal trypsin did not induce exocytosis in polarized PDEC monolayers; on the other hand, 10 microm trypsin at 37 degrees C damaged the epithelial barrier sufficiently so that it could reach and activate the serosal PAR-2 to stimulate exocytosis. Thus, in PDEC, PAR-2 activation increases [Ca(2+)](i) and activates PKC to stimulate exocytosis and mucin secretion. These functions may mediate the reported protective role of PAR-2 in different models of pancreatitis.
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PMID:Protease-activated receptor-2 increases exocytosis via multiple signal transduction pathways in pancreatic duct epithelial cells. 1844 25

MUC5B is a major mucin of the human respiratory tract, and it is not clear how MUC5B expression is regulated in various airway diseases. The goal of this study was to determine the mechanisms by which 17beta-estradiol induces MUC5B gene expression in airway epithelial cells. It was found that E2, a sex hormone, stimulates MUC5B gene overexpression by interaction with estrogen receptor alpha (ERalpha) and by acting through extracellular signal-regulated kinase 1/2 (ERK1/2)-mitogen-activated protein kinase (MAPK). Pretreatment with ER antagonist ICI 182,780 blocked both E2-induced ERK1/2-MAPK activation and MUC5B gene expression. It was also found that the activation of p90 ribosomal S 6 protein kinase 1 (RSK1), cAMP-response element-binding protein (CREB), and cAMP-response element (CRE) (-956 region of the MUC5B promoter)-responsive signaling cascades via ERK1/2 MAPK are crucial aspects of the intracellular mechanisms that mediate MUC5B gene expression. Taken together, these studies give additional insights into the molecular mechanism of hormone-induced MUC5B gene expression and enhance our understanding of abnormal mucin secretion in response to hormonal imbalances.
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PMID:Signal pathway of 17beta-estradiol-induced MUC5B expression in human airway epithelial cells. 1868 42

Mucus secretion is an important protective mechanism for the luminal lining of open tubular organs, but mucin overproduction in the respiratory tract can exacerbate the inflammatory process and cause airway obstruction. Production of MUC5AC, a predominant gel-forming mucin secreted by airway epithelia, can be induced by various inflammatory mediators such as prostaglandins. The two major prostaglandins involved in inflammation are PGE(2) and PGF(2alpha). PGE(2)-induced mucin production has been well studied, but the effect of PGF(2alpha) on mucin production remains poorly understood. To elucidate the effect and underlying mechanism of PGF(2alpha) on MUC5AC production, we investigated the signal transduction of PGF(2alpha) associated with this effect using normal human tracheobronchial epithelial cells. Our results demonstrated that PGF(2alpha) induces MUC5AC overproduction via a signaling cascade involving protein kinase C, ERK, p90 ribosomal S6 protein kinase, and CREB. The regulation of PGF(2alpha)-induced MUC5AC expression by CREB was further confirmed by cAMP response element-dependent MUC5AC promoter activity and by interaction between CREB and MUC5AC promoter. The abrogation of all downstream signaling activities via suppression of each signaling molecule along the pathway indicates that a single pathway from PGF(2alpha) receptor to CREB is responsible for inducing MUC5AC overproduction. As CREB also mediates mucin overproduction induced by PGE(2) and other inflammatory mediators, our findings have important clinical implications for the management of airway mucus hypersecretion.
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PMID:CREB mediates prostaglandin F2alpha-induced MUC5AC overexpression. 1920 89

Diabetes mellitus (DM) is a widespread disease with high morbidity and health care costs. An experimental animal model was employed, using morphological and biochemical methods, to investigate the effects of DM on the expression and compartmentation of salivary gland proteins. The distribution of proline-rich proteins (PRP), submandibular mucin (Muc10) and the regulatory (RI and RII) subunits of cyclic AMP-dependent protein kinase type I and type II was determined in the parotid and submandibular (SMG) glands of rats treated with streptozotocin. Quantitative immunocytochemistry of secretory granules in diabetic glands revealed decreases of 30% for PRP in both the parotid and SMG, and a 40% decrease in Muc10 in the SMG. Immunogold labelling showed that RII decreased in nuclei and the cytoplasm in diabetic acinar cells while labelling of secretory granules was similar in control and diabetic parotid. Electrophoresis and Western blotting of tissue extracts of two secretory proteins showed that the response to DM and insulin treatment was gland specific: PRP showed little change in the SMG, but decreased in the parotid in DM and was partially restored after insulin treatment. Photoaffinity labelling showed only RI present in the SMG and mainly RII in the parotid. The results of this and previous studies demonstrating highly specific changes in salivary protein expression indicate that the oral environment is significantly altered by DM, and that oral tissues and their function can be compromised. These findings may provide a basis for future studies to develop tests using saliva for diabetic status or progression in humans.
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PMID:Protein expression in salivary glands of rats with streptozotocin diabetes. 1965 99

Human epithelial mucin, the major glycoprotein component of mucus, plays a critical role in host innate defense response against invading microbes by facilitating the mucociliary clearance. Excess mucin production, however, overwhelms the mucociliary clearance, resulting in not only defective mucosal defense but also conductive hearing loss in the middle ear and mucus obstruction in the airway. Indeed, mucus overproduction is a hall-mark of otitis media (OM) and chronic obstructive pulmonary diseases (COPD). Thus, tight regulation of mucin production plays an important role in maintaining an appropriate balance between beneficial and detrimental outcomes. We previously reported that Streptococcus pneumoniae (S. pneumoniae) up-regulates MUC5AC mucin expression via a positive MAPK ERK1/2 and a negative JNK1/2 signaling pathway. However, the signaling components including the up-stream activators and the down-stream transcription factors involved in these two path-ways remain largely unknown. In the present study, we showed that positive regulation of MUC5AC mucin expression by ERK1/2 is dependent on Ras-Raf-1 signaling pathway, whereas the negative regulation of MUC5AC expression by JNK1/2 is dependent on MEKK3. Moreover, transcriptional factor AP-1 acts as a key regulator for both of the positive and negative regulation of MUC5AC mucin expression as evidenced by mutagenesis analysis of two AP-1 sites in the promoter region of human MUC5AC mucin gene. Ras-Raf1-ERK1/2-dependent AP-1 activation positively regulates MUC5AC mucin induction by S. pneumoniae, whereas MEKK3-JNK1/2-dependent AP-1 activation negatively regulates it. Therefore, our data unveiled a novel signaling mechanism underlying the tight regulation of MUC5AC mucin induction by S. pneumoniae and may lead to the development of new therapeutic strategy for reducing mucus overproduction in both OM and COPD.
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PMID:Differential regulation of Streptococcus pneumoniae-induced human MUC5AC mucin expression through distinct MAPK pathways. 1995 40

MUC2 is a major secretory mucin normally expressed by goblet cells of the intestine, but is aberrantly expressed in colonic neoplasia. Bile acids have been implicated in colorectal carcinogenesis and, therefore, we sought to determine the effects of bile acids on MUC2 expression and regulation in colon cancer cells. Since deoxycholic acid (DCA), a secondary bile acid, has been reported to be a potent mucin secretagogue and tumor promoter, DCA-treated HM3 colon cancer cells were analyzed using promoter-reporter assays of the 5' flanking region of the MUC2 gene. Chemical inhibitors, mutant reporter constructs and EMSA showed that DCA upregulates MUC2 transcription via multiple pathways involving activation of EGFR/PKC/Ras/Raf-1/MEK1/ERK/CREB, PI3/Akt/IkappaB/NF-kappaB and p38/MSK1/CREB while DCA induced MUC2 transcription is inhibited by JNK/c-Jun/AP-1 pathway. These results provide new insight into the complex molecular mechanisms involved in the regulation of mucin gene by bile acids in colon cancer cells that may contribute to further elucidation of colorectal carcinogenesis.
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PMID:Bile acid regulates MUC2 transcription in colon cancer cells via positive EGFR/PKC/Ras/ERK/CREB, PI3K/Akt/IkappaB/NF-kappaB and p38/MSK1/CREB pathways and negative JNK/c-Jun/AP-1 pathway. 2019 39

Exocytosis is evoked by intracellular signals, including Ca(2+) and protein kinases. We determined how such signals interact to promote exocytosis in exocrine pancreatic duct epithelial cells (PDECs). Exocytosis, detected using carbon-fiber microamperometry, was stimulated by [Ca(2+)](i) increases induced either through Ca(2+) influx using ionomycin or by activation of P2Y2 or protease-activated receptor 2 receptors. In each case, the exocytosis was strongly potentiated when cyclic AMP (cAMP) was elevated either by activating adenylyl cyclase with forskolin or by activating the endogenous vasoactive intestinal peptide receptor. This potentiation was completely inhibited by H-89 and partially blocked by Rp-8-Br-cAMPS, inhibitors of protein kinase A. Optical monitoring of fluorescently labeled secretory granules showed slow migration toward the plasma membrane during Ca(2+) elevations. Neither this Ca(2+)-dependent granule movement nor the number of granules found near the plasma membrane were detectably changed by raising cAMP, suggesting that cAMP potentiates Ca(2+)-dependent exocytosis at a later stage. A kinetic model was made of the exocytosis stimulated by UTP, trypsin, and Ca(2+) ionophores with and without cAMP increase. In the model, without a cAMP rise, receptor activation stimulates exocytosis both by Ca(2+) elevation and by the action of another messenger(s). With cAMP elevation the docking/priming step for secretory granules was accelerated, augmenting the releasable granule pool size, and the Ca(2+) sensitivity of the final fusion step was increased, augmenting the rate of exocytosis. Presumably both cAMP actions require cAMP-dependent phosphorylation of target proteins. cAMP-dependent potentiation of Ca(2+)-induced exocytosis has physiological implications for mucin secretion and, possibly, for membrane protein insertion in the pancreatic duct. In addition, mechanisms underlying this potentiation of slow exocytosis may also exist in other cell systems.
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PMID:Cyclic AMP potentiates Ca2+-dependent exocytosis in pancreatic duct epithelial cells. 2042 76


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