Functions both as protein phosphatase and as transcriptional coactivator for SIX1, and probably also for SIX2, SIX4 and SIX5 (PubMed:12500905, PubMed:23435380). 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 (PubMed:19351884). Its function as histone phosphatase may contribute to its function in transcription regulation during organogenesis. Plays an important role in hypaxial muscle development together with SIX1 and DACH2; in this it is functionally redundant with EYA1 (PubMed:12500905). H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Binds 1 Mg(2+) ion per subunit. Interacts with DACH2 and SIX1, and probably with SIX2, SIX4 and SIX5. Interacts with CAPN8 (By similarity). Interacts with GNAZ and GNAI2; this precludes interaction with SIX1. Retained in the cytoplasm via interaction with GNAZ and GNAI2 (PubMed:10906137). Interaction with SIX1, SIX2, SIX4 or SIX5 is required for translocation to the nucleus (PubMed:10906137, PubMed:12500905). Experimental confirmation may be lacking for some isoforms. Highest expression in muscle with lower levels in kidney, placenta, pancreas, brain and heart. At the begin of fourth week of development detected in cytoplasm of somite cells. Between the sixth and eighth week of development detected in cytoplasm of limb bud cells. Belongs to the HAD-like hydrolase superfamily. EYA family. Extended N-terminus.