Optogenetic user's guide to Opto-GPCRs.

Optogenetics has taken biomedical research by storm. The power and precision at which light-gated ion channels control cellular excitability in diverse biological systems has convinced researchers of an optical future. Growing interest in optical methods has sparked the development of multiple new optogenetic tools, which allow precise control of numerous cellular processes. Among these new tools are the light-activatable G-protein coupled receptors (GPCRs) or Opto-GPCRs. The extent of the GPCR family, which in humans alone encompasses approximately 800 different proteins, and the immense therapeutic potential of Opto-GPCRs predict a big future for this juvenile field. Here the different approaches taken to design Opto-GPCRs are reviewed, outlining the advantages and disadvantages of each method for physiological and potential clinical application.