ARHGDIB and acute lymphoblastic leukemia: Here, we find that RhoGDI2 is phosphorylated by Src and ABL1 in response to CXCR4 stimulation by CXCL12 in T-ALL cell lines and that RhoGDI2 decreases the CXCR4-mediated T-ALL cell line migration toward CXCL12 (Figures 1, 2).