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. NNF1 is required for a number of nuclear functions. Cells depleted of NNF11 or containing a temperature-sensitive NNF1 mutation have elongated microtubules and become bi- and multinucleate. They also have a fragmented nucleolus and accumulate poly(A)+ RNA inside the nucleus. {ECO:0000269|PubMed:12455957; ECO:0000269|PubMed:14633972}.