Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P51812 (mitogen-activated protein)
 10,636 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Annexin XI (CAP-50) is a probable target protein of calcyclin. Being different from other annexins, annexin XI localizes mainly in nuclei of cultured fibroblasts. In rat embryonic fibroblasts transformed by Rous sarcoma virus oncogene, SR-3Y1 cells, phosphorylation of annexin XI was increased on both serine and threonine residues (Ser < Thr), compared with findings in control 3Y1 cells. The amount of phosphorylated annexin XI was approximately 8.5% of the total cellular annexin XI and the phosphorylated annexin XI migrated slightly slower on SDS-polyacrylamide gel electrophoresis than did the non-phosphorylated form of annexin XI. Phosphorylated annexin XI was recovered in the cytoplasmic fraction and did not bind to phosphatidylserine vesicle in the presence of high Ca2+ (over 1 mM). Annexin XI was phosphorylated by mitogen-activated protein (MAP) kinase, which was reported to be activated in v-src-transformed fibroblast (Gupta, S. K., Gallego, C. Johnson, G.L. and Heasley, L.E. (1992) J. Biol. Chem. 267, 7987-7990), on both serine and threonine residues (Ser >> Thr) in vitro. Comparative phosphopeptide mappings analyzed by reverse-phase high performance liquid chromatography suggested that the sites phosphorylated in situ in SR-3Y1 cells are distinct from the sites by MAP kinase. Annexin XI phosphorylated by MAP kinase still possessed the ability to bind to phosphatidylserine vesicle. These results suggest that annexin XI is a substrate for some Ser/Thr kinase(s) which is activated in v-src-transformed cells and that the phosphorylation may regulate the function of annexin XI in living cells.
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PMID:Phosphorylation of annexin XI (CAP-50) in SR-3Y1 cells. 839 45

Tyrosine kinase activity of v-Src from Rous sarcoma virus (RSV) inhibits the differentiation of quail myoblasts. To clarify the inhibitory mechanism, we focused on the signaling pathways from v-Src. When the activation of the Ras/MAP (mitogen-activated protein) kinase pathway was inhibited by a dominant-negative mutant of Ras or PD98059, a specific inhibitor of p42 MAP kinase kinase, differentiation was restored; muscle specific proteins were expressed and myotubes formed even under active conditions of v-Src. Wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase (P13-kinase), showed no effects on the inhibition by v-Src. These findings suggest that v-Src activates the Ras/MAP kinase signaling pathway, but not the P13-kinase pathway, and inhibits the differentiation. However, the myotubes derived from the dominant-negative Ras did not form actin fibers, suggesting that myofibril assembly is regulated by other pathway(s) from v-Src.
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PMID:Ras/MAP kinase pathway is associated with the control of myotube formation but not myofibril assembly in quail myoblasts transformed with Rous sarcoma virus. 1183 57