The AP‐1 repressor, JDP2, is a bona fide substrate for the c‐Jun N‐terminal kinase

Abstract
The Jun dimerization protein 2 (JDP2) is a novel member of the basic leucine zipper family of transcription factors. JDP2 binds DNA as a homodimer and heterodimer with ATF2 and Jun proteins but not with c‐Fos proteins. JDP2 overexpression represses activating protein 1 transcription activity. Whereas JDP2 mRNA and protein levels are stable following different cell stimuli, JDP2 is rapidly phosphorylated upon UV irradiation, oxidative stress and low levels of translation inhibitor. The c‐Jun N‐terminal kinase phosphorylates JDP2 both in vitro and in vivo. JDP2 contains a putative consensus JNK docking‐site and a corresponding phosphoacceptor site. Substitution of threonine 148 to an alanine residue blocks JNK‐dependent JDP2 phosphorylation. Our data indicate that JDP2 is a bona fide substrate for the c‐Jun N‐terminal kinase. The precise role of JDP2 phosphorylation on its function is not yet known.