title: Antipeptide antibodies against a Torpedo cysteine-string protein.
abstract: An antipeptide antiserum was raised against the C-terminal undecapeptide of a Torpedo cysteine-string protein (csp), a putative subunit or modulator of presynaptic calcium channels. This antiserum was shown to identify selectively the 27-kDa in vitro translation product of the csp cRNA both by immunoprecipitation and on immunoblots. When affinity-purified anti-csp antibodies were used to probe immunoblots of membrane proteins from Torpedo electric organ or liver, specific immunoreactivity was detected only in electric organ. This immunoreactivity was associated principally with a single protein species of about 34 kDa. These results indicate that csp immunoreactivity is detectably expressed in electroplax, a heavily innervated tissue, but not in liver, which should have an appreciably lower abundance of presynaptic calcium channel proteins. Moreover, the increased relative molecular mass of csp in electric organ (compared with in vitro translated material) implies that csp is posttranslationally modified. Finally, immunoblot analysis of either intact, alkali-treated, or solubilized membrane fractions of electric organ reveals that csp is predominantly a membrane protein.
authors.affiliation: Department of Pharmacology, Jerry Lewis Neuromuscular Research Center, UCLA School of Medicine 90024.
authors.forename: A
authors.initials: A
authors.lastname: Mastrogiacomo
authors.forename: C J
authors.initials: CJ
authors.lastname: Evans
authors.forename: C B
authors.initials: CB
authors.lastname: Gundersen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology*; D003902:Detergents; D004557:Electric Organ / Q000378:metabolism; D015151:Immunoblotting; D008099:Liver / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D008969:Molecular Sequence Data; D017830:Octoxynol; D010446:Peptide Fragments / Q000276:immunology*; D011092:Polyethylene Glycols; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D018075:RNA, Complementary / Q000235:genetics; D014101:Torpedo / Q000378:metabolism*
chemical_list: D000906:Antibodies; D003902:Detergents; D008565:Membrane Proteins; D010446:Peptide Fragments; D018075:RNA, Complementary; D011092:Polyethylene Glycols; D017830:Octoxynol; C010615:Nonidet P-40