RhoG GTPase Controls a Pathway That Independently Activates Rac1 and Cdc42Hs
AUTOR(ES)
Gauthier-Rouvière, Cécile
FONTE
The American Society for Cell Biology
RESUMO
RhoG is a member of the Rho family of GTPases that shares 72% and 62% sequence identity with Rac1 and Cdc42Hs, respectively. We have expressed mutant RhoG proteins fused to the green fluorescent protein and analyzed subsequent changes in cell surface morphology and modifications of cytoskeletal structures. In rat and mouse fibroblasts, green fluorescent protein chimera and endogenous RhoG proteins colocalize according to a tubular cytoplasmic pattern, with perinuclear accumulation and local concentration at the plasma membrane. Constitutively active RhoG proteins produce morphological and cytoskeletal changes similar to those elicited by a simultaneous activation of Rac1 and Cdc42Hs, i.e., the formation of ruffles, lamellipodia, filopodia, and partial loss of stress fibers. In addition, RhoG and Cdc42Hs promote the formation of microvilli at the cell apical membrane. RhoG-dependent events are not mediated through a direct interaction with Rac1 and Cdc42Hs targets such as PAK-1, POR1, or WASP proteins but require endogenous Rac1 and Cdc42Hs activities: coexpression of a dominant negative Rac1 impairs membrane ruffling and lamellipodia but not filopodia or microvilli formation. Conversely, coexpression of a dominant negative Cdc42Hs only blocks microvilli and filopodia, but not membrane ruffling and lamellipodia. Microtubule depolymerization upon nocodazole treatment leads to a loss of RhoG protein from the cell periphery associated with a reversal of the RhoG phenotype, whereas PDGF or bradykinin stimulation of nocodazole-treated cells could still promote Rac1- and Cdc42Hs-dependent cytoskeletal reorganization. Therefore, our data demonstrate that RhoG controls a pathway that requires the microtubule network and activates Rac1 and Cdc42Hs independently of their growth factor signaling pathways.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=25357Documentos Relacionados
- The GTPase-activating protein n-chimaerin cooperates with Rac1 and Cdc42Hs to induce the formation of lamellipodia and filopodia.
- Critical Activities of Rac1 and Cdc42Hs in Skeletal Myogenesis: Antagonistic Effects of JNK and p38 Pathways
- Immunological Function in Mice Lacking the Rac-Related GTPase RhoG
- The TRE17 Oncogene Encodes a Component of a Novel Effector Pathway for Rho GTPases Cdc42 and Rac1 and Stimulates Actin Remodeling
- Coiling Phagocytosis of Borrelia burgdorferi by Primary Human Macrophages Is Controlled by CDC42Hs and Rac1 and Involves Recruitment of Wiskott-Aldrich Syndrome Protein and Arp2/3 Complex