Dephosphorylation of the C-terminal Tyrosyl Residue of the DNA Damage-related Histone H2A.X Is Mediated by the Protein Phosphatase Eyes Absent

Navasona Krishnan,Dae Gwin Jeong,Suk-Kyeong Jung,Seong Eon Ryu,Andrew Xiao,C David Allis,Seung Jun Kim,Nicholas K Tonks

doi:10.1074/jbc.c900032200

Abstract

In mammalian cells, the DNA damage-related histone H2A variant H2A.X is characterized by a C-terminal tyrosyl residue, Tyr-142, which is phosphorylated by an atypical kinase, WSTF. The phosphorylation status of Tyr-142 in H2A.X has been shown to be an important regulator of the DNA damage response by controlling the formation of gammaH2A.X foci, which are platforms for recruiting molecules involved in DNA damage repair and signaling. In this work, we present evidence to support the identification of the Eyes Absent (EYA) phosphatases, protein-tyrosine phosphatases of the haloacid dehalogenase superfamily, as being responsible for dephosphorylating the C-terminal tyrosyl residue of histone H2A.X. We demonstrate that EYA2 and EYA3 displayed specificity for Tyr-142 of H2A.X in assays in vitro. Suppression of eya3 by RNA interference resulted in elevated basal phosphorylation and inhibited DNA damage-induced dephosphorylation of Tyr-142 of H2A.X in vivo. This study provides the first indication of a physiological substrate for the EYA phosphatases and suggests a novel role for these enzymes in regulation of the DNA damage response.

Highlights

In mammalian cells, the DNA damage-related histone H2A variant H2A.X is characterized by a C-terminal tyrosyl residue, Tyr-142, which is phosphorylated by an atypical kinase, WSTF
We present evidence to support the identification of the Eyes Absent (EYA) phosphatases, protein-tyrosine phosphatases of the haloacid dehalogenase superfamily, as being responsible for dephosphorylating the C-terminal tyrosyl residue of histone H2A.X
We report that a striking feature of the EYA domain (ED) of EYA2, domain has a typical ␣/␤-hydrolase fold and possesses the three as revealed by the crystal structure, is the clustering of acidic resi- conserved sequence motifs and the bound magnesium ion that dues around the active site to present a negatively charged surface. are common to the active site of members of the haloacid dehalogenase (HAD) family

Summary

ACCELERATED PUBLICATION

Dephosphorylation of the C-terminal Tyrosyl Residue of the DNA Damage-related Histone H2A.X Is Mediated by the Protein Phosphatase Eyes Absent*. We present evidence to support the identification of the Eyes Absent (EYA) phosphatases, protein-tyrosine phosphatases of the haloacid dehalogenase superfamily, as being responsible for dephosphorylating the C-terminal tyrosyl residue of histone H2A.X. We demonstrate that EYA2 and EYA3 displayed specificity for Tyr-142 of H2A.X in assays in vitro. A HAD phosphatase known as Dullard has been shown to dephosphorylate the phosphatidic acid phosphatase lipin, functioning in a phosphatase cascade that regulates nuclear membrane biogenesis [6] In these cases, the HADs are functioning as protein-Ser/Thr phosphatases.

RESULTS

MATERIALS AND METHODS