Part of the MIS12 complex, which may be fundamental for kinetochore formation and proper chromosome segregation during mitosis. Essential for proper kinetochore microtubule attachments. Component of the MIS12 complex composed of MIS12, DSN1, NSL1 and PMF1. Also interacts with KNL1, CBX3, CBX5, NDC80 and ZWINT. Associated with the kinetochore. Belongs to the mis12 family.