Selective activation of G-protein subtypes by vertebrate and invertebrate rhodopsins

FEBS Lett. 1998 Nov 13;439(1-2):110-4. doi: 10.1016/s0014-5793(98)01340-4.

Abstract

We have quantitatively investigated specificities in activating G-protein subtype by bovine and squid rhodopsins to examine whether or not the phototransduction cascade in each of the photoreceptor cells is determined by the colocalization of a large amount of G-protein subtype (Gt or Gq). In contrast to the efficient activation of respective Gt and Gq, bovine and squid rhodopsins scarcely activated G-protein counterparts. Exchange of alpha- and betagamma-subunits of Gt and Gq indicated the critical role of the alpha-subunit in specific binding to respective rhodopsins. Thus the specific recognition of G-protein subtype by each rhodopsin is a major mechanism in determining the phototransduction cascade.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding, Competitive
  • Cattle
  • Decapodiformes
  • GTP-Binding Proteins / classification
  • GTP-Binding Proteins / isolation & purification
  • GTP-Binding Proteins / metabolism*
  • Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
  • Receptors, Cell Surface / metabolism
  • Rhodopsin / metabolism*
  • Time Factors

Substances

  • Receptors, Cell Surface
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Rhodopsin
  • GTP-Binding Proteins