Methods and constructs are provided for controlling processes in live animals, plants or microbes via genetically engineered near-infrared light-activated or light-inactivated proteins including chimeras including the photosensory modules of bacteriohytochromes and output modules that possess enzymatic activity and/or ability to bind to DNA, RNA, protein, or small molecules. DNA encoding these proteins are introduced as genes into live animals, plants or microbes, where their activities can be turned on by near-infrared light, controlled by the intensity of light, and turned off by near-infrared light of a different wavelength than the activating light. These proteins can regulate diverse cellular processes with high spatial and temporal precision, in a nontoxic manner, often using external light sources. For example, near-infrared light-activated proteins possessing nucleotidyl cyclase, protein kinase, protease, DNA-binding and RNA-binding activities are useful to control signal transduction, cell apoptosis, proliferation, adhesion, differentiation and other cell processes.