Chapter category: Signal Transduction

GTPases in Semaphorin Signalling

This chapter appears in the following book:

Semaphorins: Receptor and Intracellular Signaling Mechanisms

Edited by: R. Jeroen Pasterkamp
ISBN: 978-0-387-70955-0
» Get more information about this book at landesbioscience.com «

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A hallmark of semaphorin receptors is their interaction with multiple GTPases. Plexins, the signal transducing component of semaphorin receptors, directly associate with several GTPases. In addition, they not only recruit guaninine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs) but also are the only known integral membrane proteins that show a catalytic activity as GAPs for small GTPases. GTPases function upstream of semaphorin receptors and regulate the activity of plexins through an interaction with the cytoplasmic domain. The association of Plexin-A1 (Sema3A receptor) or Plexin-B1 (Sema4D receptor) with the GTPase Rnd1 and ligand-dependent receptor clustering are required for their activity as R-Ras GAPs. The GTPases R-Ras and Rho function downstream of plexins and are required for the repulsive effects of semaphorins. In this review, I will focus on the role of GTPases in signalling by two plexins that have been analyzed in most detail, Plexin-A1 and Plexin-B1.

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Chapter category: Signal Transduction

GTPases in Semaphorin Signalling

Additional chapters from this book:

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