title: A short peptide is a protein kinase C (PKC) alpha-specific substrate.
abstract: The purpose of this study was to find protein kinase C (PKC) isozyme-specific peptides. A peptide library containing 1772 sequences was designed using Scansite and screened by MALDI-TOF MS and kinase activity assays for PKC isozyme-specificity. A peptide (Alphatomega; H-FKKQGSFAKKK-NH(2)) with high specificity for PKC alpha relative to other isozymes was identified. The peptide was phosphorylated to a greater extent by tissue lysates from B16 melanoma, HepG2, and human breast cancer, which had higher levels of activated PKC alpha, when compared to normal skin, liver, and human breast tissue lysates, respectively. Moreover, addition of Ro-31-7549, an inhibitor with great specificity for PKC alpha, to the phosphorylation reaction caused a dose-dependent reduction in phosphorylation, but no inhibition was identified with the addition of rottlerin and H-89. These results show that this peptide has great potential as a PKC alpha-specific substrate.
authors.affiliation: CREST, Japan Science and Technology Corporation, Kawaguchi-Shi, Saitama, Japan.
authors.forename: Jeong-Hun
authors.initials: JH
authors.lastname: Kang
authors.forename: Daisuke
authors.initials: D
authors.lastname: Asai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamada
authors.forename: Riki
authors.initials: R
authors.lastname: Toita
authors.forename: Jun
authors.initials: J
authors.lastname: Oishi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mori
authors.forename: Takuro
authors.initials: T
authors.lastname: Niidome
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Katayama
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D019151:Peptide Library; D010455:Peptides / Q000378:metabolism*; D010766:Phosphorylation; D051571:Protein Kinase C-alpha / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013379:Substrate Specificity
chemical_list: D019151:Peptide Library; D010455:Peptides; D051571:Protein Kinase C-alpha