Functions both as protein phosphatase and as transcriptional coactivator for SIX1, and probably also for SIX2, SIX4 and SIX5 (PubMed:10490620, PubMed:17098221). Tyrosine phosphatase that dephosphorylates 'Tyr-142' of histone H2AX (H2AXY142ph) and promotes efficient DNA repair via the recruitment of DNA repair complexes containing MDC1. 'Tyr-142' phosphorylation of histone H2AX plays a central role in DNA repair and acts as a mark that distinguishes between apoptotic and repair responses to genotoxic stress. Its function as histone phosphatase may contribute to its function in transcription regulation during organogenesis (By similarity). Plays an important role in hypaxial muscle development together with SIX1 and DACH2; in this it is functionally redundant with EYA1 (By similarity). H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Binds 1 Mg(2+) ion per subunit. Probably interacts with SIX2, SIX4 and SIX5. Interacts with DACH2. Interacts with GNAZ and GNAI2; this retains EYA2 in the cytoplasm and prevents its translocation into the nucleus and transcriptional activity (By similarity). Interacts with SIX1. Interacts with CAPN8. Retained in the cytoplasm via interaction with GNAZ and GNAI2 (By similarity). Interaction with SIX1, SIX2, SIX4 or SIX5 is required for translocation to the nucleus. Extensively expressed in cranial placodes, branchial arches, CNS and developing eye and nose. Low expression in lung with little or no expression in skin, liver, intestine and kidney. Predominantly expressed in the upper one-third of the oxyntic mucosa and in most regions of the pyloric mucosa. No visible phenotype. In contrast, mice lacking both Eya1 and Eya2 display complete embryonic lethality, due to severe defects in muscle development, including the absence of the diaphragm, the absence of ventral hypaxial muscles of the trunk and muscles in forelimbs and hindlimbs, similar to the phenotype of mice lacking both Six1 and Six4. While Six1 is normally expressed in these mice, it does not activate transcription from cognate promoter elements, and does not activate transcription of Pax3. Belongs to the HAD-like hydrolase superfamily. EYA family.