RAC1 and Miyoshi myopathy: CXCR4 was shown to induce MM cell migration via signaling through Rho GTPases; RhoA and Rac1 were shown to play key roles in SDF1-induced adhesion of MM cells to BM stromal cells, and inhibition by small molecule-specific inhibitors for Rac1 GTPase and for ROCK (the main effector protein downstream of RhoA) showed that RhoA was important for both adhesion and chemotaxis, whereas Rac1 was important for adhesion but not chemotaxis in MM [76].