Distinct requirement for an intact dimer interface in wild-type, V600E and kinase-dead B-Raf signalling.

摘要: The dimerisation of Raf kinases involves a central cluster within the kinase domain, dimer interface (DIF). Yet, importance DIF for signalling potential wild-type B-Raf (B-Raf(wt)) and its oncogenic counterparts remains unknown. Here, we show that plays pivotal role activity B-Raf(wt) several gain-of-function (g-o-f) mutants. In contrast, B-Raf(V600E), B-Raf(insT) B-Raf(G469A) oncoproteins are remarkably resistant to mutations in DIF. However, compared with B-Raf(wt), B-Raf(V600E) displays extended protomer contacts, increased homodimerisation incorporation into larger protein complexes. Raf-1(wt) mediated triggered by Ras as well paradoxical activation Raf-1 kinase-inactivated require an intact Surprisingly, is not required between B-Raf, which was inactivated D594A mutation, sorafenib or PLX4720. This suggests MEK/ERK represents two-step mechanism consisting DIF-dependent transactivation. Our data further implicate target against Ras-driven Raf-mediated (paradoxical) ERK activation.