The Aurora-B-mediated phosphorylation of SHCBP1 at the S634 site attenuates the interaction of SHCBP1 with RACGAP1 and prevents the premature localization of SHCBP1 to the central spindle, ensuring that RAC1 inactivation caused by RACGAP promotes the ingression of the cytokinetic furrow during early anaphase [15], which is consistent with our finding that SHCBP1 suppresses RACGAP-mediated hydrolysis of GTP-RAC1 but not RhoA and CDC42 in bladder cancer cells, leading to the accumulation of active RAC1. Here, RAC1 is linked to urinary bladder cancer.