Part of the MIS12 complex which is required for normal chromosome alignment and segregation and kinetochore formation during mitosis. May act as a cotranscription partner of NFE2L2 involved in regulation of polyamine-induced transcription of SSAT. {ECO:0000269|PubMed:10419538; ECO:0000269|PubMed:11256947; ECO:0000269|PubMed:15502821; ECO:0000269|PubMed:16585270}.