Part of the MIS12 complex which is required for normal chromosome alignment and segregation and for kinetochore formation during mitosis (PubMed:12515822, PubMed:15502821, PubMed:16585270). Essential for proper kinetochore microtubule attachments (PubMed:23891108). 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.