title: Engineered Substrate-Specific Delta PKC Antagonists to Enhance Cardiac Therapeutics.
abstract: Most protein kinases phosphorylate multiple substrates, each of which induces different and sometimes opposing functions. Determining the role of phosphorylation of each substrate following a specific stimulus is challenging but is essential to elucidate the role of that substrate in the signaling event. Here we describe a rational approach to identify inhibitors of delta protein kinase C (δPKC), each inhibiting the phosphorylation of only one of δPKC's substrates. δPKC regulates many signaling events and we hypothesized that a docking inhibitor of a given substrate to δPKC should selectively abrogate the phosphorylation of only that substrate, without affecting the phosphorylation of the other δPKC substrates. Here we report the development of selective inhibitors of three δPKC substrates (in vitro Kd≈3 nm); two greatly reduced ischemia-induced cardiac injury with an IC50of ≈200 nm and the third had no effect, indicating that its respective substrate phosphorylation by δPKC has no role in the response to cardiac ischemia and reperfusion. The three inhibitors are highly specific; even at 1 μm, the phosphorylation of other δPKC protein substrates was unaffected. The rationale we describe is likely applicable for the development of other substrate-specific inhibitors as well.
authors.affiliation: Department of Chemical and Systems Biology, School of Medicine Stanford, Stanford University, CA, 94305-5174, USA.
authors.forename: Nir
authors.identifier: 0000-0002-2578-1048
authors.initials: N
authors.lastname: Qvit
authors.affiliation: Department of Chemical and Systems Biology, School of Medicine Stanford, Stanford University, CA, 94305-5174, USA.
authors.forename: Opher S
authors.initials: OS
authors.lastname: Kornfeld
authors.affiliation: Department of Chemical and Systems Biology, School of Medicine Stanford, Stanford University, CA, 94305-5174, USA.
authors.forename: Daria
authors.initials: D
authors.lastname: Mochly-Rosen
mesh_terms: D000818:Animals; D055808:Drug Discovery; D006801:Humans; D062105:Molecular Docking Simulation; D009203:Myocardial Infarction / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation / Q000187:drug effects; D051745:Protein Kinase C-delta / Q000037:antagonists & inhibitors* / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D013379:Substrate Specificity / Q000187:drug effects
chemical_list: D047428:Protein Kinase Inhibitors; D051745:Protein Kinase C-delta
keywords: docking site; ischemia; peptides; protein kinase C (PKC); protein-protein interaction