Ras recruits Raf‐1 to the plasma membrane for activation by tyrosine phosphorylation.

摘要: A central feature of signal transduction downstream both receptor and oncogenic tyrosine kinases is the Ras-dependent activation a protein kinase cascade consisting Raf-1, Mek (MAP kinase) ERKs kinases). To study role activity in we have examined properties p74Raf-1 Src that are necessary for p74Raf-1. We show mammalian cells by requires pp60Src to be myristoylated ability interact with p21Ras-GTP. The Ras/Raf interaction required p21Ras-GTP bring plasma membrane phosphorylation at 340 or 341, probably membrane-bound pp60Src. When expressed activated 5-fold; however, when co-expressed Ras Src, Raf-1 25-fold this associated further 3-fold increase phosphorylation. Thus, limiting component bringing Using mutants Tyr340/341, addition these sites, there an additional step resulting from recruiting membrane. least two different steps.