Defects in cytokinesis, actin reorganization and the contractile vacuole in cells deficient in RhoGDI.

ABSTRACT: Rho GDP-dissociation inhibitors (RhoGDIs) modulate the cycling of Rho GTPases between active GTP-bound and inactive GDP-bound states. We identified two RhoGDI homologues in DICTYOSTELIUM: GDI1 shares 51-58% similarity to RhoGDIs from diverse species. GDI2 is more divergent (40-44% similarity) and lacks the N-terminal regulatory arm characteristic for RhoGDI proteins. Both are cytosolic proteins and do not relocalize upon reorganization of the actin cytoskeleton. Using a two-hybrid approach, we identified Rac1a/1b/1c, RacB, RacC and RacE as interacting partners for GDI1. Cells lacking GDI1 are multinucleate, grow slowly and display a moderate pinocytosis defect, but rates of phagocytosis are unaffected. Mutant cells present prominent actin-rich protrusions, and large vacuoles that are conti

SUBMITTER: Rivero F 

PROVIDER: S-EPMC126189 | biostudies-literature | 2002 Sep

REPOSITORIES: biostudies-literature