RanBP2 and SENP3 function in a mitotic SUMO2/3 conjugation-deconjugation cycle on Borealin.
The ubiquitin-like SUMO system controls cellular key functions, and several lines of evidence point to a critical role of SUMO for mitotic progression. However, in mammalian cells mitotic substrates of sumoylation and the regulatory components involved are not well defined. Here, we identify Borealin, a component of the chromosomal passenger complex (CPC), as a mitotic target of SUMO. The CPC, which additionally comprises INCENP, Survivin, and Aurora B, regulates key mitotic events, including chromosome congression, the spindle assembly checkpoint, and cytokinesis. We show that Borealin is preferentially modified by SUMO2/3 and demonstrate that the modification is dynamically regulated during mitotic progression, peaking in early mitosis. Intriguingly, the SUMO ligase RanBP2 interacts with the CPC, stimulates SUMO modification of Borealin in vitro, and is required for its modification in vivo. Moreover, the SUMO isopeptidase SENP3 is a specific interaction partner of Borealin and catalyzes the removal of SUMO2/3 from Borealin. These data thus delineate a mitotic SUMO2/3 conjugation-deconjugation cycle of Borealin and further assign a regulatory function of RanBP2 and SENP3 in the mitotic SUMO pathway.
Pubmed ID: 18946085 RIS Download
Animals | Aurora Kinase B | Aurora Kinases | COS Cells | Cell Cycle Proteins | Cercopithecus aethiops | Chromosomal Proteins, Non-Histone | Cysteine Endopeptidases | HeLa Cells | Humans | Inhibitor of Apoptosis Proteins | Microtubule-Associated Proteins | Mitosis | Molecular Chaperones | Nuclear Pore Complex Proteins | Protein-Serine-Threonine Kinases | Small Ubiquitin-Related Modifier Proteins | Two-Hybrid System Techniques | Ubiquitins