Component of the kinetochore, a multiprotein complex that assembles on centromeric DNA and attaches chromosomes to spindle microtubules, mediating chromosome segregation and sister chromatid segregation during meiosis and mitosis. Component of the inner kinetochore COMA complex, which connects centromere-associated proteins and the outer kinetochore. COMA interacts with other inner kinetochore proteins to form the inner kinetochore constitutive centromere-associated network (CCAN), which serves as a structural platform for outer kinetochore assembly. Component of the heterotetrameric kinetochore subcomplex COMA, which consists of fta2, fta7, mal2 and mis17 (By similarity). The COMA subcomplex is part of a larger constitutive centromere-associated network (CCAN) (also known as central kinetochore Sim4 complex in fission yeast), which is composed of at least cnl2, cnp3, cnp20, fta1, fta2, fta3, fta4, fta6, fta7, mal2, mhf1, mhf2, mis6, mis15, mis17, sim4 and wip1 (PubMed:15369671, PubMed:16079914). Interacts with mis6 and mis15 (PubMed:15369671). Belongs to the CENP-U/AME1 family.