title: Rational design of a selective antagonist of epsilon protein kinase C derived from the selective allosteric agonist, pseudo-RACK peptide.
abstract: We have previously shown that domains involved in binding of protein kinase C (PKC) isozymes to their respective anchoring proteins (RACKs) and short peptides derived from these domains are PKC isozyme-selective antagonists. We also identified PKC isozyme-selective agonists, named psiRACK peptides, derived from a sequence within each PKC with high homology to its respective RACK. We noted that all the psiRACK sequences within each PKC isozyme have at least one non-homologous amino acid difference from their corresponding RACK that constitutes a charge change. Based on this information, we have devised here a new approach to design an isozyme-selective PKC antagonist, derived from the psiRACK sequence. We focused on epsilonPKC psiRACK peptide, where the pseudo-epsilonRACK sequence (psiepsilonRACK; HDAPIGYD; corresponding to epsilonPKC85-92) is different in charge from the homologous RACK-derived sequence (NNVALGYD; corresponding to epsilonRACK285-292) in the second amino acid. Here we show that changing the charge of the psiepsilonRACK peptide through a substitution of only one amino acid (aspartate to asparagine) resulted in a peptide with an opposite activity on the same cell function and a substitution for aspartate with an alanine resulted in an inactive peptide. These data support our hypothesis regarding the mechanism by which pseudo-RACK peptide activates PKC in heart cells and suggest that this approach is applicable to other signaling proteins with inducible protein-protein interactions.
authors.affiliation: Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305-5332, USA.
authors.forename: Tamar
authors.initials: T
authors.lastname: Liron
authors.forename: Leon E
authors.initials: LE
authors.lastname: Chen
authors.forename: Hanita
authors.initials: H
authors.lastname: Khaner
authors.forename: Alice
authors.initials: A
authors.lastname: Vallentin
authors.forename: Daria
authors.initials: D
authors.lastname: Mochly-Rosen
mesh_terms: D000494:Allosteric Regulation; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D004330:Drosophila / Q000378:metabolism; D015195:Drug Design; D008297:Male; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D051744:Protein Kinase C-epsilon / Q000037:antagonists & inhibitors* / Q000378:metabolism; D021381:Protein Transport; D051381:Rats; D015398:Signal Transduction
chemical_list: D010446:Peptide Fragments; D051744:Protein Kinase C-epsilon