Core component of nucleosome which plays a central role in DNA double strand break (DSB) repair. 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. 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. The [ST]-Q motif constitutes a recognition sequence for kinases from the PI3/PI4-kinase family. Phosphorylated to form H2AS128ph (gamma-H2A) in response to DNA double-strand breaks (DSBs) generated by exogenous genotoxic agents and by stalled replication forks. Phosphorylation is dependent on the DNA damage checkpoint kinases rad3/ATR and tel1/ATM, spreads on either side of a detected DSB site and may mark the surrounding chromatin for recruitment of proteins required for DNA damage signaling and repair. Gamma-H2A is required for recruiting crb2, a modulator of DNA damage checkpoint signaling, to DSB sites. Gamma-H2A is removed from the DNA prior to the strand invasion-primer extension step of the repair process and subsequently dephosphorylated. Dephosphorylation is necessary for efficient recovery from the DNA damage checkpoint. Acetylated by esa1 to form H2AK4ac and H2AK7ac. In contrast to vertebrates and insects, its C-terminus is not monoubiquitinated. Belongs to the histone H2A family. To ensure consistency between histone entries, we follow the 'Brno' nomenclature for histone modifications, with positions referring to those used in the literature for the 'closest' model organism. Due to slight variations in histone sequences between organisms and to the presence of initiator methionine in UniProtKB/Swiss-Prot sequences, the actual positions of modified amino acids in the sequence generally differ. In this entry the following conventions are used: H2AK4ac = acetylated Lys-5; H2AK7ac = acetylated Lys-9; H2AS128ph = phosphorylated Ser-128.