查看文章

PKN is a serine/threonine protein kinase with a catalytic domain homologous to the protein kinase C family and unique N-terminal leucine zipper-like sequences. Using analyses with the yeast two-hybrid system andin vitrobinding assay, we found that the regulatory domain of PKN interacted with vimentin. We then examined whether PKN would phosphorylate vimentinin vitro.Vimentin proved to be an excellent substrate for PKN, and the phosphorylation of vimentin by PKN occurred in the head domain with the result of a nearly complete inhibition of its filament formationin vitro.Similar results were also obtained with another type III intermediate filament protein, glial fibrillary acidic protein (GFAP). These results raise the possibility that PKN may regulate filament structures of vimentin and GFAP by domain-specific phosphorylation.