Histone H3-like nucleosomal protein that is specifically found in centromeric nucleosomes. Replaces conventional H3 in the nucleosome core of centromeric chromatin at the inner plate of the kinetochore. The presence of CENPA subtly modifies the nucleosome structure and the way DNA is wrapped around the nucleosome and gives rise to protruding DNA ends that are less well-ordered and rigid compared to nucleosomes containing histone H3. May serve as an epigenetic mark that propagates centromere identity through replication and cell division (By similarity). Required for recruitment and assembly of kinetochore proteins, and as a consequence required for progress through mitosis, chromosome segregation and cytokinesis (PubMed:27499292). Component of centromeric nucleosomes, where DNA is wrapped around a histone octamer core. The octamer contains two molecules each of H2A, H2B, CENPA and H4 assembled in one CENPA-H4 heterotetramer and two H2A-H2B heterodimers. CENPA modulates the DNA-binding characteristics of nucleosomes so that protruding DNA ends have higher flexibility than in nucleosomes containing conventional histone H3. Inhibits binding of histone H1 to nucleosomes, since histone H1 binds preferentially to rigid DNA linkers that protrude from nucleosomes. Nucleosomes containing CENPA also contain histone H2A variants such as MACROH2A and H2A.Z/H2AZ1. The CENPA-H4 heterotetramer is more compact and structurally more rigid than corresponding H3-H4 heterotetramers. Can assemble into nucleosomes that contain both CENPA and histone H3.3; these nucleosomes interact with a single CENPC chain. Heterotrimer composed of HJURP, CENPA and histone H4, where HJURP interacts with the dimer formed by CENPA and histone H4 and prevents tetramerization of CENPA and H4. Component of the CENPA-NAC complex, at least composed of CENPA, CENPC, CENPH, CENPM, CENPN, CENPT and CENPU. Interacts (via CATD domain) with HJURP; the interaction is direct and is required for its localization to centromeres. Interacts with CENPC, CENPN and CENPT; interaction is direct. Part of a centromere complex consisting of CENPA, CENPT and CENPW. Identified in centromere complexes containing histones H2A, H2B and H4, and at least CENPA, CENPB, CENPC, CENPT, CENPN, HJURP, SUPT16H, SSRP1 and RSF1. Can self-associate. The CENPA-H4 heterotetramer can bind DNA by itself (in vitro). Interacts with CDK1, PPP1CA and RBBP7. Localizes exclusively in the kinetochore domain of centromeres. Occupies a compact domain at the inner kinetochore plate stretching across 2 thirds of the length of the constriction but encompassing only one third of the constriction width and height. Phosphorylation at Ser-62 during early mitosis abolishes association with chromatin and centromeres and results in dispersed nuclear location. The CATD (CENPA targeting domain) region is responsible for the more compact structure of nucleosomes containing CENPA. It is necessary and sufficient to mediate the localization into centromeres. Poly-ADP-ribosylated by PARP1. Trimethylated by NTMT1 at the N-terminal glycine after cleavage of Met-1. Methylation is low before incorporation into nucleosomes and increases with cell cycle progression, with the highest levels in mitotic nucleosomes. Phosphorylated by CDK1 at Ser-62 during early mitosis; this abolishes association with chromatin and centromeres, prevents interaction with HJURP and thereby prevents premature assembly of CENPA into centromeres. Dephosphorylated at Ser-62 by PPP1CA during late mitosis. Belongs to the histone H3 family.