PRC1: Proteins and Enzymes

Novel human protein Protein regulator of cytokinesis 1 (PRC1) is involved in cytokinesis. PRC1 is a good substrate for several CDKs in vitro and is phosphorylated in vivo at sites that are phosphorylated by CDK in vitro, strongly suggesting that PRC1 is an in vivo CDK substrate. PRC1 protein levels are high during S and G2/M and drop dramatically after cells exit mitosis and enter G1. PRC1 is a nuclear protein in interphase, becomes associated with mitotic spindles in a highly dynamic manner during mitosis, and localizes to the cell mid-body during cytokinesis (1). PRC1, a mitotic spindle-associated Cdk substrate that is essential to cell cleavage, is a microtubule binding and bundling protein both in vivo and in vitro. Over expression of PRC1 extensively bundles interphase microtubules, but does not affect early mitotic spindle organization (2). PRC1 has been shown to down-regulate the GAP activity of MgcRac-GAP during the metaphase and thereby contributes to the correct formation of the spindle (3).