Mitotic spindle checkpoint protein Bub1/Mad3 (IPR015661)

Short name: Bub1/Mad3

Overlapping homologous superfamilies


Family relationships



This represents the mitotic checkpoint serine/threonine-protein kinase Bub1.

Saccharomyces cerevisiae Bub1 has a paralogue, Mad3, which is also included in this entry. Bub1 forms a complex with Mad1 and Bub3 that is crucial for preventing cell cycle progression into anaphase in the presence of spindle damage [PMID: 12769845], while Mad3 is a component of the spindle-assembly complex consisting of Mad2, Mad3, Bub3 and Cdc20 [PMID: 10704439]. Mad3 contains a D-box and two KEN- boxes, which function together to mediate Cdc20-Mad3 interaction. Mad3 and an anaphase-promoting complex (APC) substrate, Hsl1, compete for Cdc20 binding in a D-box- and KEN-box-dependent manner [PMID: 17369399].

Similar to its yeast homologues, human Bub1 is a critical component of the mitotic checkpoint that delays the onset of anaphase until all chromosomes have established bipolar attachment to the microtubules. In interphase cells it localises to centrosomes and suppresses centrosome amplification via regulating Plk1 activity [PMID: 19503101]. Mutations in the human Bub1 gene have been linked to cancers [PMID: 10395177, PMID: 9521327].

GO terms

Biological Process

GO:0007094 mitotic spindle assembly checkpoint

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.