Optogenetic technologies combine technologies from optics and genetics to use light to control cell behaviors and molecular processes in real-time.
Optogenetic reporters are one of the most important tools of optogenetics. Most of these indicator proteins are composed of naturally evolved fluorescent proteins that have been tuned by protein engineering in conjunction with a variety of other proteins that evolved to sense biological parameters such as ion concentrations or membrane potential. These biosensors are genetically encoded, which means that living cells can be instructed by genetic modification to synthesize these fluorescent proteins. The cell’s fluorescence then indicates the biological parameter of interest.

Thomas Knöpfel, RIKEN Brain Science Institute, Japan, and colleagues from the University of Alberta, Edmonton, Canada, systematize the established transduction mechanisms of these engineered proteins. They also outline some of the challenges that need to be overcome to move this field of research forward. One of the most pressing challenges is the development of proteins with stable bright far-red or infra-red fluorescence, long wavelength light that penetrates tissue very well.

• Optogenetic Reporters,
  Spencer C. Alford, Jiahui Wu, Yongxin Zhao, Robert E. Campbell, Thomas Knöpfel,
  Biol. Cell 2013, 105, 14–29.
  DOI: 10.1111/boc.201200054