Mutations in RVS161 and RVS167 yeast genes induce identical phenotypes associated to actin cytoskeleton disorders. The whole Rvs161 protein is similar to the amino-terminal part of Rvs167p, thus defining a RVS domain. In addition to this domain, Rvs167p contains a central glycine-proline-alanine rich domain and a SH3 domain. To assess the function of these different domains we have expressed recombinant Rvs proteins in rvs mutant strains. Phenotype analysis has shown that the RVS and SH3 domains are necessary for phenotypical complementation, whereas the GPA domain is not. Moreover, we have demonstrated that the RVS domains from Rvs161p and Rvs167p have distinct roles, and that the SH3 domain needs the specific RVS domain of Rvs167p to function. These results suggest that Rvs161p and Rvs167p play distinct roles, while acting together in a common function.