title: Characterization of a selective CaMKII peptide inhibitor.
abstract: Analogs of potent CaMKinase II inhibitor, CaM-KNtide, were prepared to explore new structural requirements for the inhibitory activity. The full potency of CaMKII inhibition by CaM-KIINα is contained within a minimal region of 19 amino acids. Here, analysis of the homologous CaM-KIINβ showed that a 17 mer peptide (CN17β) was the shortest sequence that still retained useful inhibitory potency. Ala substitution of almost any residue of CN17β dramatically reduced potency, except for substitution of P3, R14, and V16. Fusion with the tat sequence generated the cell-penetrating inhibitor version tat-5. This tat-5 fusion peptide maintained selectivity for CaMKII over CaMKI and CaMKIV, and appeared to slightly further enhance potency (IC50 ∼30 nM). Within a breast cancer cell line and in primary human fibroblasts, tat-5 inhibited the Erk signaling pathway and proliferation without any measurable cytotoxicity. Structural analysis of CN17β by CD and NMR indicated an α-helix conformation in the Leu6-Arg11 segment well overlapping with the crystal structure of 21-residue segment of CaM-KNtide bound to the kinase domain of CaMKII.
authors: Depart. of Pharmaceutical and Toxicological Chemistry, University of Naples Federico II, Naples, Italy.
authors: Isabel
authors: I
authors: Gomez-Monterrey
authors: Marina
authors: M
authors: Sala
authors: Maria Rosaria
authors: MR
authors: Rusciano
authors: Sara
authors: S
authors: Monaco
authors: Angela Serena
authors: AS
authors: Maione
authors: Guido
authors: G
authors: Iaccarino
authors: Paolo
authors: P
authors: Tortorella
authors: Anna Maria
authors: AM
authors: D'Ursi
authors: Mario
authors: M
authors: Scrima
authors: Alfonso
authors: A
authors: Carotenuto
authors: Giuseppe
authors: G
authors: De Rosa
authors: Alessia
authors: A
authors: Bertamino
authors: Ermelinda
authors: E
authors: Vernieri
authors: Paolo
authors: P
authors: Grieco
authors: Ettore
authors: E
authors: Novellino
authors: Maddalena
authors: M
authors: Illario
authors: Pietro
authors: P
authors: Campiglia
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000037:antagonists & inhibitors* / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D006801:Humans; D061986:MCF-7 Cells; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D011921:Rats, Inbred WKY; D013329:Structure-Activity Relationship
chemical_list: D000970:Antineoplastic Agents; C583782:CN17beta peptide; D010446:Peptide Fragments; D047428:Protein Kinase Inhibitors; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2