Spatiotemporal optical control of Gαq-PLCβ interactions

Cells experience time-varying and spatially heterogeneous chemokine signals in vivo, activating cell surface proteins, including G protein-coupled receptors (GPCRs). The Gq pathway activation by GPCRs is a major signaling axis with a broad physiological and pathological significance. Compared to other G members, GqGTP activates many crucial effectors, including PLC{beta} (Phospholipase C{beta}) and Rho GEFs (Rho guanine nucleotide exchange factors). PLC{beta} regulates many key processes, such as hematopoiesis, synaptogenesis, and cell cycle, and is therefore implicated in terminal - debilitating diseases, including cancer, epilepsy, Huntingtons Disease, and Alzheimers Disease. However, due to a lack of genetic and pharmacological tools, examining how the dynamic regulation of PLC{beta} signaling controls cellular physiology has been difficult. Since activated PLC{beta} induces several abrupt cellular changes, including cell morphology, examining how the other pathways downstream of Gq-GPCRs contribute to the overall signaling has also been difficult. Here we show the engineering, validation, and application of a highly selective and efficient optogenetic inhibitor (Opto-dHTH) to completely disrupt GqGTP-PLC{beta} interactions reversibly in user-defined cellular-subcellular regions on optical command. Using this newly gained PLC{beta} signaling control, our data indicate that the molecular competition between RhoGEFs and PLC{beta} for GqGTP determines the potency of Gq-GPCR-governed directional cell migration.