Comparative interactome analysis reveals distinct and overlapping properties of Raf family kinases.

The three mammalian Raf proteins (A-Raf, B-Raf, and C-Raf) are key components of the MAPK pathway. Although diverse functions have been proposed for Raf kinases, it is still not clear how interacting proteins contribute to differences in the signaling functions of the three Raf kinases. Here, we report the comparative interactomes of the three Raf kinases under serum-starved and EGF-stimulated conditions. We identified nearly 400 novel interacting proteins; some interacted with all three isoforms while others interacted exclusively with one or two. Comparing the interactomes of the three Raf kinases under different conditions revealed Raf proteins perform distinct functions through specific interactions. Our interactome data help define the differences between the three Raf kinases and may uncover new functions or regulatory mechanisms. Knowledge of Raf kinase protein-protein interactions will help us to investigate the function of specific pathways in the future.