Component of the CENPA-NAC (nucleosome-associated) complex, a complex that plays a central role in assembly of kinetochore proteins, mitotic progression and chromosome segregation. The CENPA-NAC complex recruits the CENPA-CAD (nucleosome distal) complex and may be involved in incorporation of newly synthesized CENPA into centromeres. Required for chromosome congression and efficiently align the chromosomes on a metaphase plate. {ECO:0000269|PubMed:14536089, ECO:0000269|PubMed:16875666, ECO:0000269|PubMed:18007590}. This is the function of CENPH (centromere protein H, Ensembl gene identifier ENSG00000153044).