AIMS: The discovery of a specific prorenin receptor (PRR) suggests a biological function of prorenin independently from angiotensin I production. In the present study we investigated the role of PRR on smooth muscle cell (SMC) migration. METHODS AND RESULTS: PRR was expressed in human mammary arteries and in cultured human aortic SMCs. Prorenin induced SMC migration in a dose dependent manner, assessed by Boyden chamber chemotaxis assay, and increased SMC random motility, determined by video microscopy. The prorenin decoy peptide inhibited SMC migration in response to prorenin and knock down of PRR, by siRNA, completely affected the migratory response to prorenin, demonstrating that the chemotactic action of prorenin is mediated by the PRR. Prorenin induced cytoskeleton reorganization and lamellipodia formation, and increased the intracellular levels of both RhoA-GTP and Rac1-GTP through PRR. These effects were required for SMC migration since the suppression, by siRNA, of either Rac1 or RhoA GTP-bound forms completely blocked PRR-mediated chemotactive effect. Prorenin also induced the formation of larger focal adhesions and cleavage of the focal adhesion kinase (pp125(FAK)) in two main fragments with molecular weight of 50 and 90 kDa. The generation of these two fragments of pp125(FAK) was reduced by the calpain inhibitor ALLN, which also inhibited SMC migration in response to prorenin. CONCLUSIONS: These results demonstrated that prorenin is a chemotactic factor for human aortic SMCs expressing PRR. This effect is elicited through a cytoskeleton and focal adhesion re-organization, RhoA and Rac1 activation and calpain-mediated pp125(FAK) cleavage.