The Sim4 complex is required for loading the DASH complex onto the kinetochore via interaction with dad1. Has a role in the maintenance of core chromatin structure and kinetochore function. Required for the localization of mis6 and cnp1 to the kinetochore. Required for the establishment of a functional centromere where it has a role in silencing. Also has a role in regulating metaphase spindle length. {ECO:0000269|PubMed:12242294; ECO:0000269|PubMed:16079914; ECO:0000269|PubMed:8887647}.