Forms a kinetochore complex with SPC105 which is required for kinetochore binding by a discrete subset of kMAPs (BIM1, BIK1 and SLK19) and motors (CIN8, KAR3). Involved in kinetochore-microtubule binding and the spindle assembly checkpoint. Component of the SPC105 complex composed of at least SPC105 and KRE28. The SPC105 complex interacts with the MIND and NDC80 complexes at the centromere. Localizes to the nuclear side of the spindle pole body.