Structure of human Mad1 C-terminal domain reveals its involvement in kinetochore targeting.

ABSTRACT: The spindle checkpoint prevents aneuploidy by delaying anaphase onset until all sister chromatids achieve proper microtubule attachment. The kinetochore-bound checkpoint protein complex Mad1-Mad2 promotes the conformational activation of Mad2 and serves as a catalytic engine of checkpoint signaling. How Mad1 is targeted to kinetochores is not understood. Here, we report the crystal structure of the conserved C-terminal domain (CTD) of human Mad1. Mad1 CTD forms a homodimer and, unexpectedly, has a fold similar to those of the kinetochore-binding domains of Spc25 and Csm1. Nonoverlapping Mad1 fragments retain detectable kinetochore targeting. Deletion of the CTD diminishes, does not abolish, Mad1 kinetochore localization. Mutagenesis studies further map the functional interface of Mad1 CTD

SUBMITTER: Kim S 

PROVIDER: S-EPMC3340083 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature