QM IS A NOVEL ZINC-BINDING TRANSCRIPTION REGULATORY PROTEIN - ITS BINDING TO C-JUN IS REGULATED BY ZINC IONS AND PHOSPHORYLATION BY PROTEIN-KINASE-C

A novel method was developed for cloning of zinc-binding proteins, We used Zn-65(2+) as a probe to screen a human lung cDNA library, and iso lated QM using this approach. QM appears to be a negative regulator of c-Jun that acts by binding to the leucine zipper region of c-Jun, We demonstrated that QM bound zinc ions and that such binding was necessa ry for the interaction of QM with c-Jun. We also showed that protein k inase C introduced about 1 mol of phosphate into 1 mol of QM. The bind ing of QM to c-Jun was decreased by 60% when QM had been phosphorylate d. These results suggest that QM is a novel zinc-binding transcription regulatory protein and that interaction between QM and c-Jun is regul ated by zinc ions and phosphorylation. (C) 1997 Academic Press