Fig. 2.

Summary of the functions, interacting partners, and targets of the spindle checkpoint kinases Bub1 and BubR1. The domain architectures of Bub1, BubR1, and its orthologue Mad3 are illustrated, and the contribution of each motif to the mitotic checkpoint or to chromosome congression and biorientation is shown. A solid arrow indicates a clear requirement for the motif for a particular function across evolution, whereas a dashed arrow indicates that the contribution of the domain remains controversial. The gray arrow indicates our own unpublished results. Bold arrows indicate the interaction partners identified to date for each of the domains and interaction motifs highlighted in Bub1 and Mad3/BubR1. In the case of Cenp-F, Cenp-E, and MCAK, their kinetochore recruitment is Bub1 kinase independent.