title: Disturbing GTP-binding protein function through microinjection into the visual cell of Limulus.
abstract: We have tested the action of three agents microinjected into the ventral nerve photoreceptor of Limulus on the electrical response to dim light. 1. A monoclonal antibody (mAb 4A) against the G alpha subunit of frog transducin reduces the size of the receptor current to 60%, suggesting an interaction with G alpha in the Limulus photoreceptor. 2. Injection of Clostridium botulinum ADP-ribosyltransferase C3 reduces the size to 46%; latency is not affected. The results imply that small GTP-binding proteins play a functional role in photoreception of invertebrates. 3. Injection of GDP-beta-S reduces dose-dependently the size of the receptor current to 15% and prolongs the latency to 200%, presumably by reducing number and rate of G-protein activations.
authors.affiliation: Institut für Biologie II, RWTH Aachen, Bundesrepublik Deutschland.
authors.forename: H
authors.initials: H
authors.lastname: Stieve
authors.forename: B
authors.initials: B
authors.lastname: Niemeyer
authors.forename: K
authors.initials: K
authors.lastname: Aktories
authors.forename: H E
authors.initials: HE
authors.lastname: Hamm
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D006737:Horseshoe Crabs; D007700:Kinetics; D008027:Light; D008564:Membrane Potentials; D008845:Microinjections; D010786:Photoreceptor Cells / Q000187:drug effects / Q000502:physiology*; D011065:Poly(ADP-ribose) Polymerases / Q000494:pharmacology*; D013997:Time Factors; D015293:Transducin / Q000276:immunology / Q000502:physiology*; D014796:Visual Perception
chemical_list: D000911:Antibodies, Monoclonal; D011065:Poly(ADP-ribose) Polymerases; D015293:Transducin