Fig. 1. Examples of localization and signaling of GPCRs from intracellular membranes.
In addition to the plasma membrane GPCRs localize and signal through G proteins in compartments along the biosynthetic pathway (solid arrows) and the endolysosomal pathway (dashed arrows). Non-canonical GPCR signaling through G proteins in these membranes can proceed by distinct interactions, such as a PTHR-G protein-arrestin signaling complex, and produce distinct downstream signaling effects, including but not limited to sustained signaling, transcriptional responses, and effects on cell growth, neurotransmission, and the perception of pain.