Acts as essential component of the kinetochore MIND complex; which is required for the spindle checkpoint and kinetochore integrity. MIND plays a role in establishing a bipolar spindle-kinetochore interaction by joining kinetochore subunits contacting DNA to those contacting microtubules. {ECO:0000269|PubMed:14602074; ECO:0000269|PubMed:14633972}.