title: Tumor promoter binding of the protein kinase C C1 homology domain peptides of RasGRPs, chimaerins, and Unc13s.
abstract: Recent investigations discovered nonkinase-type phorbol ester receptors, RasGRPs, chimaerins, and Unc13s. Phorbol ester binding occurs at the cysteine-rich sequences of about 50 residues in the C1 domains of these receptors. Fifty-one-residue RasGRP C1 peptides except for RasGRP2 showed significant phorbol 12,13-dibutyrate (PDBu) binding, but the K(d) values of the RasGRP1 and RasGRP3 C1 peptides were about 10-fold larger than those for the corresponding whole enzymes. Addition of the C-terminal basic amino acid cluster decreased their K(d) values about 10-fold, suggesting that the positive charges of these C1 peptides play an important role in the PDBu binding in the presence of negatively-charged phosphatidylserine. The 51-mer chimaerin C1 peptides showed potent PDBu binding, while the Unc13 and Munc13-1 C1 peptides without sufficient positive charges hardly bound PDBu. By the rapid screening system using this C1 peptide library, 5-prenyl-indolactam-V was identified as a promising lead for the novel protein kinase C isozyme specific ligands.
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan. irie@kais.kyoto-u.ac.jp
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Irie
authors.forename: Akiko
authors.initials: A
authors.lastname: Masuda
authors.forename: Mayumi
authors.initials: M
authors.lastname: Shindo
authors.forename: Yu
authors.initials: Y
authors.lastname: Nakagawa
authors.forename: Hajime
authors.initials: H
authors.lastname: Ohigashi
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000187:drug effects; D002273:Carcinogens / Q000494:pharmacology*; D020740:Chimerin Proteins / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D006006:Glycogen Synthase / Q000737:chemistry / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000187:drug effects / Q000378:metabolism; D007769:Lactams / Q000494:pharmacology; D008024:Ligands; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011493:Protein Kinase C / Q000737:chemistry / Q000378:metabolism*
chemical_list: C098228:C1 peptide; D002273:Carcinogens; D020740:Chimerin Proteins; D004268:DNA-Binding Proteins; D020662:Guanine Nucleotide Exchange Factors; D007211:Indoles; D007527:Isoenzymes; D007769:Lactams; D008024:Ligands; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; C491790:RASGRP1 protein, human; C485548:UNC13B protein, human; D015240:Phorbol 12,13-Dibutyrate; C043969:indolactam V; D006006:Glycogen Synthase; D011493:Protein Kinase C