Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.11.18 (MAP)
 7,412 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Angiotensin II (Ang II) receptors of the AT1 subtype are coupled to heterotrimeric G nucleotide-binding proteins, G(q/11), to activate phospholipase C-beta isoforms with production of inositol 1,4,5-trisphosphate (InsP3) and diacylglycerol. The resultant release of intracellular Ca2+ and increased Ca2+ influx are major determinants of several acute cellular responses initiated by Ang II, including secretion of aldosterone from the adrenal cortex and smooth muscle contraction. However, cellular events related to more prolonged effects of Ang II, such as hypertrophic and hyperplastic responses, are triggered by intracellular signaling cascades that are less dependent on Ca2+ signals. The Ang II-induced activation of Raf-1 kinase, p42 MAP-kinase and c-fos expression in response to Ang II in adrenal glomerulosa cells does not require Ca2+ influx. Moreover, the dose-response relationships for Raf-1 activation, MAP-kinase activation and mitogenesis show significantly higher sensitivity to Ang II than the InsP3, Ca2+-release and aldosterone secretory responses. The sensitivities of both Raf-1 kinase and MAP-kinase stimulation by Ang II to the inhibitors of phosphoinositide kinases, wortmannin and LY 294002, suggest that inositol phospholipids may play a role in these activation events unrelated to their role in Ca2+ signaling. To investigate the changes of various inositides after stimulation at the single cell level, fluorescent probes were developed in which pleckstrin homology domains with distinct binding specificities to inositol phospholipids were fused to the green fluorescent protein and expressed in NIH 3T3 cells. The use of these probes revealed heterogeneity of the inositol lipid pools and their complex relationship to Ca2+ signals. The use of these tools will help to further clarify the complex role of these lipids in initiating Ca2+-dependent and -independent signaling responses.
 ...
PMID:Signaling events activated by angiotensin II receptors: what goes before and after the calcium signals. 988 5

Platelet activation results in shape change, release of granule contents, aggregation and clot retraction. An intense intracellular 'machinery' is engaged to achieve these functions. Thrombin is one of the most important agonists for platelet recruitment and aggregation which is mediated by the binding of fibrinogen to its adhesive receptor: the glycoprotein (GP) IIb/IIIa complex or integrin alphaIIbbeta(3). The numerous biological processes consecutive to thrombin binding to platelet membrane are mainly controlled by phosphorylation mechanisms organized into signalling pathways. Schematically, the phospholipase Cbeta pathway activated by G protein coupled to the seven transmembrane thrombin receptors, provides the first intracellular relay and would generate regulators such as protein kinase C, phosphorylated pleckstrin but also modifications of the intracellular domain of beta(3). This inside-out signalling would lead to some changes in the extracellular domain of GPIIb/IIIa increasing access of fibrinogen to the receptor. Ligand interaction with GPIIb/IIIa induced reorganization of the cytoskeleton and would mediate the outside-in signals which involve a series of intracellular events including tyrosine kinases, phosphatidylinositol 3 kinases, MAP kinases and phosphatases. Some of these pathways and/or signalling metabolites could be associated to some well-characterized platelet functions: cortactin phosphorylation is involved in platelet shape change, phosphatidylinositol 3 kinase (p85) in the stabilisation of platelet aggregates and MAP kinase (p44) in postaggregation events. But in fact the sequence of events which has been described has to be viewed as integrated networks. At least three biochemical processes govern the highly integrated organization to send just the appropriate quanta of signal for a specific need: the reorganisation of the cytoskeleton following the binding of fibrinogen to alphaIIbbeta(3), the structure of the signal transducers that contain SH2, SH3, and PH domains leading to the formation of macromolecules of signalling and the crosstalk phenomena between the different pathways. Elucidating the mechanisms of such networks becomes an increasingly exciting project.
 ...
PMID:Platelet signal transduction pathways: could we organize them into a 'hierarchy'? 1049 30

Gab1 is a member of the Gab/DOS (Daughter of Sevenless) family of adapter molecules, which contain a pleckstrin homology (PH) domain and potential binding sites for SH2 and SH3 domains. Gab1 is tyrosine phosphorylated upon stimulation of various cytokines, growth factors, and antigen receptors in cell lines and interacts with signaling molecules, such as SHP-2 and phosphatidylinositol 3-kinase, although its biological roles have not yet been established. To reveal the functions of Gab1 in vivo, we generated mice lacking Gab1 by gene targeting. Gab1-deficient embryos died in utero and displayed developmental defects in the heart, placenta, and skin, which were similar to phenotypes observed in mice lacking signals of the hepatocyte growth factor/scatter factor, platelet-derived growth factor, and epidermal growth factor pathways. Consistent with these observations, extracellular signal-regulated kinase mitogen-activated protein (ERK MAP) kinases were activated at much lower levels in cells from Gab1-deficient embryos in response to these growth factors or to stimulation of the cytokine receptor gp130. These results indicate that Gab1 is a common player in a broad range of growth factor and cytokine signaling pathways linking ERK MAP kinase activation.
 ...
PMID:Role of Gab1 in heart, placenta, and skin development and growth factor- and cytokine-induced extracellular signal-regulated kinase mitogen-activated protein kinase activation. 1077 59

The Tec kinases represent the second largest family of mammalian non-receptor tyrosine kinases and are distinguished by the presence of distinct proline-rich regions and pleckstrin homology domains that are required for proper regulation and activation. Best studied in lymphocyte and mast cells, these kinases are critical for the full activation of phospholipase-C gamma (PLC-gamma) and Ca(2+) mobilization downstream of antigen receptors. However, it has become increasingly clear that these kinases are activated downstream of many cell-surface receptors, including receptor tyrosine kinases, cytokine receptors, integrins and G-protein-coupled receptors. Evidence suggests that the Tec kinases influence a wide range of signaling pathways controlling activation of MAP kinases, actin reorganization, transcriptional regulation, cell survival and cellular transformation. Their impact on cellular physiology suggests that the Tec kinases help regulate multiple cellular processes beyond Ca(2+) mobilization.
 ...
PMID:Beyond calcium: new signaling pathways for Tec family kinases. 1211 60