title: The identification and characterization of novel PKCepsilon phosphorylation sites provide evidence for functional cross-talk within the PKC superfamily.
abstract: PKCepsilon (protein kinase Cepsilon) is a phospholipid-dependent serine/threonine kinase that has been implicated in a broad array of cellular processes, including proliferation, survival, migration, invasion and transformation. Here we demonstrate that, in vitro, PKCepsilon undergoes autophosphorylation at three novel sites, Ser(234), Ser(316) and Ser(368), each of which is unique to this PKC isoform and is evolutionarily conserved. We show that these sites are phosphorylated over a range of mammalian cell lines in response to a number of different stimuli. Unexpectedly, we find that, in a cellular context, these phosphorylation events can be mediated in-trans by cPKC (classical PKC) isoforms. The functional significance of this cross-talk is illustrated through the observation that the cPKC-mediated phosphorylation of PKCepsilon at residue Ser(368) controls an established PKCepsilon scaffold interaction. Thus our current findings identify three new phosphorylation sites that contribute to the isoform-specific function of PKCepsilon and highlight a novel and direct means of cross-talk between different members of the PKC superfamily.
authors.affiliation: Protein Phosphorylation Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3PX, UK.
authors.forename: Joanne
authors.initials: J
authors.lastname: Durgan
authors.forename: Angus J
authors.initials: AJ
authors.lastname: Cameron
authors.forename: Adrian T
authors.initials: AT
authors.lastname: Saurin
authors.forename: Sarah
authors.initials: S
authors.lastname: Hanrahan
authors.forename: Nick
authors.initials: N
authors.lastname: Totty
authors.forename: Robert O
authors.initials: RO
authors.lastname: Messing
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Parker
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D017124:Conserved Sequence; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D011485:Protein Binding; D051744:Protein Kinase C-epsilon / Q000737:chemistry / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D048948:14-3-3 Proteins; D010768:Phosphoserine; D051744:Protein Kinase C-epsilon