GPR116 (Adgrf5) is a member of the adhesion class of GPCRs (AdGPCRs), which share extracellular domains containing highly conserved GPCR autoproteolysis–inducing (GAIN) domains. In the lung, GPR116 is localized to the plasma membrane of alveolar type I (AT1) and AT2 cells and its RNA is detected in pulmonary endothelial cells. GPR116 is activated by its extracellular domain to activate GNAQ/GNA11, in turn regulating secretion of pulmonary surfactant. The loss of Gpr116 causes early accumulation of surfactant in the lungs, followed producing an emphysema-like pathology. References: JCI Insight. 2017 Jun 2; 2(11): e93700.; Plos One https://doi.org/10.1371/journal.pone.0137949