Binding of Rac1, Rnd1, and RhoD to a novel Rho GTPase interaction motif destabilizes dimerization of the plexin-B1 effector domain.

ABSTRACT: Plexins are the first known transmembrane receptors that interact directly with small GTPases. On binding to certain Rho family GTPases, the receptor regulates the remodeling of the actin cytoskeleton and alters cell movement in response to semaphorin guidance cues. In a joint solution NMR spectroscopy and x-ray crystallographic study, we characterize a 120-residue cytoplasmic independent folding domain of plexin-B1 that directly binds three Rho family GTPases, Rac1, Rnd1, and RhoD. The NMR data show that, surprisingly, the Cdc42/Rac interactive binding-like motif of plexin-B1 is not involved in this interaction. Instead, all three GTPases interact with the same region, beta-strands 3 and 4 and a short alpha-helical segment of the plexin domain. The 2.0 A resolution x-ray structure shows t

SUBMITTER: Tong Y 

PROVIDER: S-EPMC2655321 | biostudies-literature | 2007 Dec

REPOSITORIES: biostudies-literature