A non-canonical Grb2–PLC-γ1–Sos cascade triggered by lipovitellin 1, an apolipoprotein B homologue
- 作者：Edith Browaeys-Poly ; Isabelle Broutin ; Anne-Fré ; dé ; rique Antoine ; Matthieu Marin ; Arlette Lescuyer ; Jean Pierre Vilain ; Arnaud Ducruix ; Katia Cailliau
- 关键词：Grb2 ; PLC-γ ; 1 ; Sos ; Lipovitellin 1 ; G2/M transition
- 刊名：Cellular Signalling
- 出版年：2007
- 期刊代码：42_08986568
- 类别：bio
- 出版时间：December 2007
- 卷：19
- 期：12
- 页码：2540-2548
- 文件大小：700 K
摘要
The injection of the Grb2 adapter in Xenopus oocytes promotes G2/M transition without stimulation from a receptor only the first day after the oocytes removal from the ovaries. This cell cycle reinitiation is Ras-dependent and requires the SH2 and SH3 domains of Grb2. The SH2 domain of Grb2 binds the tyrosine phosphorylated lipovitellin1, a homologue of the human apolipoprotein B. The N-SH3 domain of Grb2 is linked to a proline-rich sequence of the C2 domain of PLC-γ1, PLC-γ1 itself is linked, through its SH3 domain, to the C-terminal proline-rich region of Sos. When Grb2–PLC-γ1–Sos is associated, PLC-γ1 is not phosphorylated on Y783 but shows a phospholipase activity. Inhibition of lipovitellin 1 or PLC-γ1 avoids Grb2-induced cell cycle reinitiation. Therefore, the Grb2–lipovitellin 1 association is the starting point of a novel signaling pathway, where PLC-γ1 binds Grb2 and recruits Sos.