Evidence that phospholipase C-γ2 interacts with SLP-76, Syk, Lyn, LAT and the Fc receptor γ-chain after stimulation of the collagen receptor glycoprotein VI in human platelets
Evidence that phospholipase C-γ2 interacts with SLP-76, Syk, Lyn, LAT and the Fc receptor γ-chain after stimulation of the collagen receptor glycoprotein VI in human platelets
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DOI：
10.1046/j.1432-1327.1999.00560.x
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发表时间：
1999-08-01
期刊：
影响因子：
--
通讯作者：
Watson, SP
中科院分区：
文献类型：
--
作者：
Gross, BS;Melford, SK;Watson, SP
Platelet activation by collagen is mediated by the sequential tyrosine phosphorylation of the Fc receptor gamma-chain (FcR gamma-chain), which is part of the collagen receptor glycoprotein VI, the tyrosine kinase Syk and phospholipase C-gamma 2 (PLC-gamma 2). In this study tyrosine-phosphorylated proteins that associate with PLC-gamma 2 after stimulation by a collagen-related peptide (CRP) were characterized using glutathione S-transferase fusion proteins of PLC-gamma 2 Src homology (SK) domains and by immunoprecipitation of endogenous PLC-gamma 2. The majority of the tyrosine-phosphorylated proteins that associate with PLC-gamma 2 bind to its C-terminal SH2 domain. These were found to include PLC-gamma 2, Syk, SH2-domain-containing leucocyte protein of 76 kDa (SLP-76), Lyn, linker for activation of T cells (LAT) and the FcR gamma-chain. Direct association was detected between PLC-gamma 2 and SLP-76, and between PLC-gamma 2 and LAT upon CRP stimulation of platelets by far-Western blotting. FcR gamma-chain and Lyn were found to co-immunoprecipitate with PLC-gamma 2 as well as with unidentified 110-kDa and 75-kDa phosphoproteins. The absence of an in vivo association between Syk and PLC-gamma 2 in platelets is in contrast with that for PLC-gamma 1 and Syk in B cells. The in vivo function of PLC-gamma 2 SH2 domains was examined through measurement of Ca2+ increases in mouse megakaryocytes that had been microinjected with recombinant proteins. This revealed that the C-terminal SH2 domain is involved in the regulation of PLC-gamma 2. These data indicate that the C-terminal SH2 domain of PLC-gamma 2 is important for PLC-gamma 2 regulation through possible interactions with SLP-76, Syk, Lyn, LAT and the FcR gamma-chain.
