Essential component of the mitotic checkpoint, which prevents cells from prematurely exiting mitosis. Required for the assembly of the dynein-dynactin and MAD1-MAD2 complexes onto kinetochores ( ). Its function related to the spindle assembly machinery is proposed to depend on its association in the mitotic RZZ complex.
Subcellular locations: Cytoplasm, Nucleus, Chromosome, Centromere, Kinetochore, Cytoplasm, Cytoskeleton, Spindle
Dynamic pattern of localization during the cell cycle. At interphase, uniformly distributed throughout the cytoplasm and nucleus. By prophase and until late stages of prometaphase, a fraction of the total pool is concentrated at kinetochores. By metaphase, detected at kinetochores, along spindle fibers and most prominently at the poles. By late anaphase until the end of telophase, no longer detectable on kinetochores or along spindle fibers, but still present at the spindle poles.
High expression in testis.