Catalysis of the reaction: histone H2AX-serine (position 139) + ATP = histone H2AX-phosphoserine (position 139) + ADP. This reaction is the addition of a phosphate group to the serine residue at position 139 of histone variant H2AX.
Source:
GOC:yaf,
PMID:16061642,
PMID:11893489
Comment
Residue 1 of histone H2A is taken as the first residue following removal of the initiating Methionine (Met).