BubR1 Rabbit Polyclonal Antibody

Function

Human cells contain two related protein kinases, BUB1 and BUBR1, that appear to have evolved from a single ancestral BUB1 gene. Both kinases are concentrated near the surface of the kinetochore where they monitor kinetochore-microtubule interactions. BUB1 and BUBR1 bind to kinetochores and are postulated to be components of the mitotic checkpoint, which monitors kinetochore activities to determine if chromosomes have achieved alignment at the spindle equator. BUBR1 is essential for normal mitotic progression as it prevents cells from prematurely entering anaphase. BUB3 is a conserved component of the mitotic spindle assembly complex and is also involved with the essential spindle checkpoint pathway that operates during early embryogenesis.

Background References

1. Chan G.K et al. Human BUBR1 is a mitotic checkpoint kinase that monitors CENP-E functions at kinetochores and binds the cyclosome/APC. J Cell Biol 146:941-954 (1999).

2. Johnson V L et al. Bub1 is required for kinetochore localization of BubR1, Cenp-E, Cenp-F and Mad2, and chromosome congression. J Cell Sci 117:1577-1589 (2004).

Sequence Similarity

Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. BUB1 subfamily.

Tissue Specificity

Highly expressed in thymus followed by spleen. Preferentially expressed in tissues with a high mitotic index.

Post-translational Modification

Proteolytically cleaved by caspase-3 in a cell cycle specific manner. The cleavage might be involved in the durability of the cell cycle delay. Caspase-3 cleavage is associated with abrogation of the mitotic checkpoint. The major site of cleavage is at Asp-610.; Acetylation at Lys-250 regulates its degradation and timing in anaphase entry.; Ubiquitinated. Degraded by the proteasome.; Sumoylated with SUMO2 and SUMO3. The sumoylation mediates the association with CENPE at the kinetochore.; Autophosphorylated in vitro. Intramolecular autophosphorylation is stimulated by CENPE. Phosphorylated during mitosis and hyperphosphorylated in mitotically arrested cells. Phosphorylation at Ser-670 and Ser-1043 occurs at kinetochores upon mitotic entry with dephosphorylation at the onset of anaphase.

Subcellular Location

Nucleus, Cytoplasm, Cytoskeleton.

UNIPROT

SwissProt: O60566 Human

Synonyms