A general approach for engineering RTKs optically controlled with far-red light

A suite of eight optogenetic receptor tyrosine kinases controlled by conformational changes in bacterial phytochrome induced by far-red light is introduced. These optogenetic tools perform well in cells and in the brain of behaving mice. Regulation of receptor tyrosine kinase (RTK) activity is necessary for studying cell signaling pathways in health and disease. We developed a generalized approach for engineering RTKs optically controlled with far-red light. We targeted the bacterial phytochrome DrBphP to the cell surface and allowed its light-induced conformational changes to be transmitted across the plasma membrane via transmembrane helices to intracellular RTK domains. Systematic optimization of these constructs has resulted in optically regulated epidermal growth factor receptor, HER2, TrkA, TrkB, FGFR1, IR1, cKIT and cMet, named eDrRTKs. eDrRTKs induced downstream signaling in mammalian cells in tens of seconds. The ability to activate eDrRTKs with far-red light enabled spectral multiplexing with fluorescent probes operating in a shorter spectral range, allowing for all-optical assays. We validated eDrTrkB performance in mice and found that minimally invasive stimulation in the neocortex with penetrating via skull far-red light-induced neural activity, early immediate gene expression and affected sleep patterns.

Automated summary

A suite of optogenetic receptor tyrosine kinases controlled by conformational changes induced by far-red light is introduced in this study. These tools perform well in cells and in the brain of behaving mice. The development of these optically regulated RTKs allows for the study of cell signaling pathways in a non-invasive and precise manner.