Optogenetic control of cell function using engineered photoreceptors

Over the past decades, there has been growing recognition that light can provide a powerful stimulus for biological interrogation. Light-actuated tools allow manipulation of molecular events with ultra-fine spatial and fast temporal resolution, as light can be rapidly delivered and focused with sub-micrometre precision within cells. While light-actuated chemicals such as photolabile 'caged' compounds have been in existence for decades, the use of genetically encoded natural photoreceptors for optical control of biological processes has recently emerged as a powerful new approach with several advantages over traditional methods. Here, we review recent advances using light to control basic cellular functions and discuss the engineering challenges that lie ahead for improving and expanding the ever-growing optogenetic toolkit.