Activation of rhodopsin: new insights from structural and biochemical studies

Trends Biochem Sci. 2001 May;26(5):318-24. doi: 10.1016/s0968-0004(01)01799-6.


G-protein-coupled receptors (GPCRs) are involved in a vast variety of cellular signal transduction processes from visual, taste and odor perceptions to sensing the levels of many hormones and neurotransmitters. As a result of agonist-induced conformation changes, GPCRs become activated and catalyze nucleotide exchange within the G proteins, thus detecting and amplifying the signal. GPCRs share a common heptahelical transmembrane structure as well as many conserved key residues and regions. Rhodopsins are prototypical GPCRs that detect photons in retinal photoreceptor cells and trigger a phototransduction cascade that culminates in neuronal signaling. Biophysical and biochemical studies of rhodopsin activation, and the recent crystal structure determination of bovine rhodopsin, have provided new information that enables a more complete mechanism of vertebrate rhodopsin activation to be proposed. In many aspects, rhodopsin might provide a structural and functional template for other members of the GPCR family.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cattle
  • Cytoplasm / metabolism
  • GTP-Binding Proteins / metabolism
  • Guanine Nucleotide Exchange Factors / metabolism
  • Humans
  • Models, Chemical
  • Models, Molecular
  • Molecular Sequence Data
  • Photons
  • Protein Conformation
  • Receptors, Cell Surface / chemistry
  • Receptors, Cell Surface / metabolism
  • Retinal Diseases / metabolism
  • Rhodopsin / chemistry*
  • Rhodopsin / metabolism*
  • Signal Transduction


  • Guanine Nucleotide Exchange Factors
  • Receptors, Cell Surface
  • Rhodopsin
  • GTP-Binding Proteins