Maintains the proteasome and its anchor cut8 at the nucleus envelope and is required for kinetochore component proteostasis (PubMed:28974540). Proper kinetochore stoichiometry ensures the correct attachment of kinetochores to spindle microtubules during cytokinesis (PubMed:28974540, PubMed:10660053). Required for the localization of spindle assembly checkpoint (SAC) protein mad2 and bub1 to the nucleus envelope during interphase, but not their localization during mitosis (PubMed:28974540). Decreases cut8 localization to the nuclear envelope (PubMed:28974540). Increases kinetochore component protein levels, including cnp3 (PubMed:28974540). Asynchronous kinetochore segregation during metaphase, with lagging kinetochores present during anaphase B (PubMed:28974540). Increases spindle assembly checkpoint (SAC) activation and results in mitotic metaphase/anaphase transition delay (PubMed:28974540). Abnormal chromosome segregation; lagging mitotic chromosomes during anaphase B and unequal mitotic sister chromatid segregation (PubMed:28974540). Sensitive to thiabendazole (PubMed:28974540). Simultaneous disruption of spindle assembly checkpoint (SAC) proteins bub1 or mad2 results in a growth defect (PubMed:28974540).