The activity of the GTPase-activating protein CdGAP is regulated by the endocytic protein intersectin

Sarah Jenna, Natasha K. Hussain, Eric I. Danek, Ibtissem Triki, Sylwia Wasiak, Peter S. McPherson, Nathalie Lamarche-Vane

Research output: Contribution to journalArticlepeer-review

Abstract

The Rho GTPases RhoA, Rac1, and Cdc42 play a major role in regulating the reorganization of the actin cytoskeleton. We recently identified CdGAP, a novel GTPase-activating protein with activity toward Rac1 and Cdc42. CdGAP consists of a N-terminal GAP domain, a central domain, and a C-terminal proline-rich domain. Here we show that through a subset of its Src homology 3 domains, the endocytic protein intersectin interacts with CdGAP. In platelet-derived growth factor-stimulated Swiss 3T3 cells, intersectin co-localizes with CdGAP and inhibits its GAP activity toward Rac1. Intersectin-Src homology 3 also inhibits CdGAP activity in GAP assays in vitro. Although the C-terminal prolinerich domain of CdGAP is required for the regulation of its GAP activity by intersectin both in vivo and in vitro, it is not necessary for CdGAP-intersectin interaction. Our data suggest that the central domain of CdGAP is required for CdGAP-intersectin interaction. Thus, we propose a model in which intersectin binding results in a change of CdGAP conformation involving the prolinerich domain that leads to the inhibition of its GAP activity. These observations provide the first demonstration of a direct regulation of RhoGAP activity through a protein-protein interaction and suggest a function for intersectin in Rac1 regulation and actin dynamics.

Original languageEnglish (US)
Pages (from-to)6366-6373
Number of pages8
JournalJournal of Biological Chemistry
Volume277
Issue number8
DOIs
StatePublished - Feb 22 2002
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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