title: Novel peptide inhibitor of ecto-ADP-ribosyl cyclase of bone marrow stromal cell antigen-1 (BST-1/CD157).
abstract: cADP-ribose, which is produced by ecto-ADP-ribosyl cyclase of CD38 or bone marrow stromal cell antigen-1 (BST-1), is a key regulator of Ca2+-induced calcium release in an Ins(1,4,5)P3-independent manner. In the present study, we have identified a specific peptide inhibitor for ADP-ribosyl cyclase of BST-1. A 15-mer random peptide phage library was screened with a soluble form of BST-1 expressed in baculovirus-infected insect cells. After biopanning, two potent sequences reactive towards BST-1 were isolated. The two synthetic peptides corresponding to the identified sequences were shown to antagonize each other's ability to inhibit the binding of the two isolated phage to BST-1, suggesting that they bind at a common binding site on BST-1. One of the peptides (SNP-1) was shown to inhibit ADP-ribosyl cyclase activity of BST-1 in an uncompetitive manner with a Ki value of 180+/-40 nM (n=3). SNP-1 also inhibited cyclic ADP-ribose hydrolase activity of BST-1 dose-dependently. Selected phage did not cross-react with a soluble form of CD38. SNP-1 did not show any inhibitory effect on ADP-ribosyl cyclase activity of CD38, and therefore this peptide inhibitor will be useful to serve as a starting tool for understanding the roles of these intriguing ecto-enzymes. This is the first report of a specific ADP-ribosyl cyclase inhibitor.
authors.affiliation: Department of Molecular Biology, Biomolecular Engineering Research Institute, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Sato
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
authors.forename: K
authors.initials: K
authors.lastname: Ishihara
authors.forename: T
authors.initials: T
authors.lastname: Hirano
authors.forename: H
authors.initials: H
authors.lastname: Jingami
mesh_terms: D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis / Q000378:metabolism*; D000943:Antigens, Differentiation / Q000378:metabolism*; D001435:Bacteriophages / Q000235:genetics; D016367:Baculoviridae / Q000235:genetics; D001854:Bone Marrow Cells / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D058851:GPI-Linked Proteins; D007313:Insecta / Q000166:cytology / Q000378:metabolism; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000378:metabolism*; D008969:Molecular Sequence Data; D009244:NAD+ Nucleosidase / Q000378:metabolism*; D019151:Peptide Library; D010455:Peptides / Q000235:genetics / Q000494:pharmacology*; D012995:Solubility; D017154:Stromal Cells / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D004791:Enzyme Inhibitors; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D019151:Peptide Library; D010455:Peptides; D036541:ADP-ribosyl Cyclase; C087521:ADP-ribosyl cyclase 2; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1