Interaction of small G proteins with photoexcited rhodopsin

FEBS Lett. 1990 Apr 24;263(2):195-8. doi: 10.1016/0014-5793(90)81372-u.

Abstract

Bovine rod outer segment (ROS) membranes contain in addition to the heterotrimeric G protein transducin, several small GTP-binding proteins (23-27 kDa). Furthermore, these membranes contain two substrate proteins (about 22 and 24 kDa) for botulinum C3 ADP-ribosyltransferase known to ADP-ribosylate small G proteins in any mammalian cell type studied so far. Most interestingly, [32P]ADP-ribosylation of ROS membrane small G proteins by C3 is regulated by light and guanine nucleotides in a manner similar to pertussis toxin-catalyzed [32P]ADP-ribosylation of the alpha-subunit of transducin. These findings suggest that not only the heterotrimeric G protein transducin but also the C3 substrate small G proteins present in ROS membranes interact with photoexcited rhodopsin and thus contribute to its signalling action.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADP Ribose Transferases / metabolism
  • Adenosine Diphosphate Ribose / metabolism
  • Animals
  • Botulinum Toxins*
  • Cattle
  • Electrophoresis, Polyacrylamide Gel
  • Eye Proteins / metabolism*
  • GTP-Binding Proteins / metabolism*
  • Heterotrimeric GTP-Binding Proteins*
  • Light
  • Membrane Proteins / metabolism*
  • Molecular Weight
  • Pertussis Toxin
  • Retina / metabolism
  • Retinal Pigments / metabolism*
  • Rhodopsin / metabolism*
  • Transducin
  • Virulence Factors, Bordetella / metabolism

Substances

  • Eye Proteins
  • GNAT1 protein, human
  • Membrane Proteins
  • Retinal Pigments
  • Virulence Factors, Bordetella
  • Adenosine Diphosphate Ribose
  • Rhodopsin
  • ADP Ribose Transferases
  • exoenzyme C3, Clostridium botulinum
  • Pertussis Toxin
  • Botulinum Toxins
  • GTP-Binding Proteins
  • Heterotrimeric GTP-Binding Proteins
  • Transducin