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. Component of the CENPA-NAC complex, at least composed of CENPA, CENPC, CENPH, CENPM, CENPN, CENPT and CENPU. The CENPA-NAC complex interacts with the CENPA-CAD complex, composed of CENPI, CENPK, CENPL, CENPO, CENPP, CENPQ, CENPR and CENPS. Nuclear in non-confluent cells and cytoplasmic in confluent or dividing cells (By similarity). Localizes in the kinetochore domain of centromeres. Isoform 3 is highly expressed in spleen, and intermediately in heart, prostate and ovary. Isoform 3 is highly expressed in resting CD19 B-cells and B-lineage chronic lymphocytic leukemia (B-CLL) cells and weakly expressed in activated B-cells. Isoform 1 is selectively expressed in activated CD19 cells and weakly in resting CD19 B-cells. Due to intron retention.