BUB1B Recombinant Protein

This gene encodes a kinase involved in spindle checkpoint function. The protein has been localized to the kinetochore and plays a role in the inhibition of the anaphase-promoting complex/cyclosome (APC/C), delaying the onset of anaphase and ensuring proper chromosome segregation. Impaired spindle checkpoint function has been found in many forms of cancer. [provided by RefSeq, Jul 2008]

BUB1B: Essential component of the mitotic checkpoint. Required for normal mitosis progression. The mitotic checkpoint delays anaphase until all chromosomes are properly attached to the mitotic spindle. One of its checkpoint functions is to inhibit the activity of the anaphase-promoting complex/cyclosome (APC/C) by blocking the binding of CDC20 to APC/C, independently of its kinase activity. The other is to monitor kinetochore activities that depend on the kinetochore motor CENPE. Required for kinetochore localization of CENPE. Negatively regulates PLK1 activity in interphase cells and suppresses centrosome amplification. Also implicated in triggering apoptosis in polyploid cells that exit aberrantly from mitotic arrest. May play a role for tumor suppression. Interacts with CENPE, CENPF, mitosin, PLK1 and BUB3. Part of a complex containing BUB3, CDC20 and BUB1B. Interacts with anaphase-promoting complex/cyclosome (APC/C). Interacts with CASC5. Induced during mitosis. Highly expressed in thymus followed by spleen. Preferentially expressed in tissues with a high mitotic index. Kinase activity stimulated by CENPE. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. BUB1 subfamily. 3 isoforms of the human protein are produced by alternative splicing.

Protein type: BUB family; EC 2.7.11.1; Kinase, protein; Other group; Protein kinase, Other; Protein kinase, Ser/Thr (non-receptor); Tumor suppressor

Chromosomal Location of Human Ortholog: 15q15.1

Cellular Component: anaphase-promoting complex; cytoplasm; cytosol; kinetochore; outer kinetochore of condensed chromosome; perinuclear region of cytoplasm

Molecular Function: protein binding; protein kinase activity

Biological Process: anaphase-promoting complex-dependent proteasomal ubiquitin-dependent protein catabolic process; cell proliferation; meiotic sister chromatid cohesion, centromeric; mitotic cell cycle checkpoint; mitotic cell cycle spindle assembly checkpoint; negative regulation of ubiquitin-protein ligase activity during mitotic cell cycle; positive regulation of ubiquitin-protein ligase activity during mitotic cell cycle; proteasomal ubiquitin-dependent protein catabolic process; protein ubiquitination during ubiquitin-dependent protein catabolic process; sister chromatid cohesion

Disease: Colorectal Cancer; Mosaic Variegated Aneuploidy Syndrome 1; Premature Chromatid Separation Trait