View : 238 Download: 39

Mechanism of tyrosine phosphorylation and activation of phospholipase c-γ1. Tyrosine 783 phosphorylation is not sufficient for lipase activation

Title
Mechanism of tyrosine phosphorylation and activation of phospholipase c-γ1. Tyrosine 783 phosphorylation is not sufficient for lipase activation
Authors
Sekiya F.Poulin B.Kim Y.J.Rhee S.G.
Ewha Authors
이서구
SCOPUS Author ID
이서구scopusscopus
Issue Date
2004
Journal Title
Journal of Biological Chemistry
ISSN
0021-9258JCR Link
Citation
Journal of Biological Chemistry vol. 279, no. 31, pp. 32181 - 32190
Indexed
SCI; SCIE; SCOPUS WOS scopus
Document Type
Article
Abstract
Phospholipase C-γ1 (PLC-γ1) is phosphorylated on three tyrosine residues: Tyr-771, Tyr-783, and Tyr-1253. With the use of antibodies specific for each of these phosphorylation sites, we have now determined the kinetics and magnitude of phosphorylation at each site. Phosphorylation of Tyr-783, which is essential for lipase activation, was observed in all stimulated cell types examined. The extent of phosphorylation of Tyr-1253 was ∼50 to 70% of that of Tyr-783 in cells stimulated with platelet-derived growth factor (PDGF) or epidermal growth factor (EGF), but Tyr-1253 phosphorylation was not detected in B or T cell lines stimulated through B- and T-cell antigen receptors, respectively. Tyr-771 was phosphorylated only at a low level in all cells studied. In cells stimulated with PDGF, phosphorylation and dephosphorylaiion of Tyr-783 and of Tyr-1253 occurred with similar kinetics; the receptor kinase appeared to phosphorylate both sites, albeit with Tyr-783 favored over Tyr-1253, before the bound PLC-γ1 was released, and phosphorylation at the two sites occurred independently. PDGF and EGF induced similar levels of phosphorylation of Tyr-783 and of Tyr-1253 in a cell line that expressed receptors for both growth factors. However, only PDGF, not EGF, elicited substantial PLC activity, suggesting that Tyr-783 phosphorylation was not sufficient for enzyme activation. Finally, concurrent production of phosphatidylinositol 3,4,5-trisphosphate was found to contribute to the activation of phosphorylated PLC-γ1.
DOI
10.1074/jbc.M405116200
Appears in Collections:
일반대학원 > 생명·약학부 > Journal papers
Files in This Item:
Mechanism of tyrosine phosphorylation.pdf(408.89 kB) Download
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE