Disruption of the 14-3-3 Binding Site within the B-Raf Kinase Domain Uncouples Catalytic Activity from PC12 Cell Differentiation

摘要: A number of Raf-associated proteins have recently been identified, including members the 14-3-3 family phosphoserine-binding proteins. Although both positive and negative regulatory functions ascribed for interactions with Raf-1, mechanisms by which binding modulates Raf activity not fully established. We report that mutational disruption to B-Raf catalytic domain inhibits biological activity. Expression isolated (B-Rafcat) induces PC12 cell differentiation in absence nerve growth factor. By contrast, B-Rafcat mutant, S728A, was severely compromised induction differentiation. Interestingly, mutant retained significant vitro InXenopus oocytes, analogous full-length blocked progesterone-stimulated maturation activation endogenous mitogen-activated protein kinase kinase. Similarly, inhibited factor-stimulated conclude interaction is required per sebut essential couple downstream effector activation.