Direct interaction of Ras and the amino-terminal region of Raf-1 in vitro

摘要: The Ras proteins are key regulators of the growth eukaryotic cells, but their direct target enzymes, or 'effectors', unknown. protein encoded by c-raf-1 proto-oncogene is thought to function downstream p21ras because disruption Raf blocks signalling in a number systems. Here we report that amino-terminal cysteine-rich regulatory region p74c-raf-1 expressed as glutathione-S-transferase (GST) fusion binds directly with relatively high affinity (50 nM). binding strictly dependent on being active GTP-bound conformation rather than inactive GDP-bound state. Raf-GST interacts wild-type and oncogenic (Val 12) fails interact biologically inert effector mutant (Ala 38) dominant negative (Asn 17). A peptide based inhibits interaction. acts potent competitive inhibitor GTPase-activating p120GAP neurofibromin. In addition, itself displays weak GTPase-stimulating activity towards Ras. It therefore likely