PRC1 (also known as protein regulator of cytokinesis 1 and mitotic spindle-associated CDK substrate) is a member of the MAP65/ASE1 family with a molecular weight of approximately 72 kD. PRC1 localization changes with cell-cycle position and can be found in the nucleus, the mitotic spindle, and the cell mid-body. PRC1 is a mitotic spindle-associated CDK substrate protein required for cytokinesis and maintenance of the spindle midzone. PRC1 can be modified by phosphorylation and has been shown to interact with Cdc2 and Cdk2. The 6G2 antibody recognizes the human PRC1 protein and has been shown to be useful for Western blotting.