Go protein as signal transducer in the pertussis toxin-sensitive phosphatidylinositol pathway

Nature. 1990 Jan 4;343(6253):79-82. doi: 10.1038/343079a0.


Receptors stimulating phospholipase C do so through heterotrimeric GTP-binding proteins to produce two second messengers, inositol 1,4,5-trisphosphate (InsP3) and diacylglycerol. In spite of the detailed understanding of phospholipase C structure and phosphatidyl inositol signalling, the identity of the GTP-binding protein involved is so far unknown. To address this issue, we have used the Xenopus oocyte in which muscarinic receptors couple to phospholipase C through a pertussis toxin-sensitive GTP-binding protein. In this cell, InsP3 mobilizes intracellular Ca2+ to evoke a Cl- current. The magnitude of this Cl- current is proportional to the amount of InsP3 in the cell, and therefore can be used as an assay for InsP3 production. We report here that the activated alpha-subunit of the GTP-binding protein GO, when directly injected into oocytes, evokes a Cl- current by mobilizing Ca2+ from intracellular InsP3-sensitive stores. We also show that holo-GO, when injected into oocytes, can specifically enhance the muscarinic receptor-stimulated Cl- current. These data indicate that GO can serve as the signal transducer of the receptor-regulated phospholipase C in Xenopus oocytes.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Calcium / metabolism
  • Chlorides / physiology
  • GTP-Binding Proteins / physiology*
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Guanosine Triphosphate / analogs & derivatives
  • Guanosine Triphosphate / pharmacology
  • Inositol 1,4,5-Trisphosphate / physiology*
  • Microinjections
  • Oocytes
  • Pertussis Toxin*
  • Receptors, Muscarinic / physiology
  • Signal Transduction
  • Thionucleotides / pharmacology
  • Type C Phospholipases / physiology
  • Virulence Factors, Bordetella / pharmacology*
  • Xenopus laevis


  • Chlorides
  • Receptors, Muscarinic
  • Thionucleotides
  • Virulence Factors, Bordetella
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Inositol 1,4,5-Trisphosphate
  • Guanosine Triphosphate
  • Pertussis Toxin
  • Type C Phospholipases
  • GTP-Binding Proteins
  • Calcium