Phorbol ester-induced translocation of PKC epsilon to the nucleus in fibroblasts: identification of nuclear PKC epsilon-associating proteins

Abstract

We show that phorbol ester treatment of NIH 3T3 fibroblasts induces rapid translocation of PKCε from a perinuclear site to the nucleus, extending findings in PC12 and NG108-15 cells and in myocytes. We have immunoprecipitated the PKCε from nuclei isolated from phorbol ester-treated fibroblasts and identified six proteins which associate with nuclear PKCε. These have been characterised as matrin 3, transferrin, Rac GTPase activating protein 1, vimentin, β-actin and annexin II by MALDI–TOF–MS. We have confirmed that these proteins associate with PKCε by gel overlay and/or dot blotting assays. The role of these PKCε-associating proteins in the nucleus and their interaction with PKCε are considered.