Variant histone H2A which replaces conventional H2A in a subset of nucleosomes. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. May be involved in the formation of constitutive heterochromatin. May be required for chromosome segregation during cell division (By similarity). The nucleosome is a histone octamer containing two molecules each of H2A, H2B, H3 and H4 assembled in one H3-H4 heterotetramer and two H2A-H2B heterodimers. The octamer wraps approximately 147 bp of DNA. H2A or its variant H2AZ1 forms a heterodimer with H2B. H2AZ1 interacts with INCENP. Interacts (via M6 cassette) with ANP32E; leading to removal of H2A.Z/H2AZ1 from the nucleosome. Interacts with VPS72 (via N-terminal domain). Interacts with PWWP2A. Interacts with FH (when phosphorylated by PRKDC). Monoubiquitination of Lys-122 gives a specific tag for epigenetic transcriptional repression. Acetylated on Lys-5, Lys-8, Lys-12 and Lys-14 by KAT2A; KAT2A is recruited by the XPC complex in absence of DNA damage (By similarity). Acetylated on Lys-5, Lys-8 and Lys-12 during interphase; acetylation disappears at mitosis (By similarity). Acetylation by the NuA4 histone acetyltransferase complex is required for hematopoietic stem cell maintenance (By similarity). Not phosphorylated. Monomethylated on Lys-5 and Lys-8 by SETD6. SETD6 predominantly methylates Lys-8, lys-5 being a possible secondary site. Lactylated in macrophages by EP300/P300 by using lactoyl-CoA directly derived from endogenous or exogenous lactate, leading to stimulates gene transcription. Belongs to the histone H2A family.