When trafficking and signaling mix: How subcellular location shapes G protein‐coupled receptor activation of heterotrimeric G proteins

• Published in: Traffic (Copenhagen, Denmark) Vol. 20; no. 2; pp. 130 - 136
• Main Authors: Lobingier, Braden T., Zastrow, Mark
• Format: Journal Article
• Language: English
• Published: Former Munksgaard John Wiley & Sons A/S 01.02.2019; Wiley Subscription Services, Inc
• Subjects: Animals; Cell surface; Cytoplasm; Endocytosis; endosome; Endosomes - metabolism; G protein; G protein-coupled receptors; GPCR; Humans; Intracellular signalling; Membrane trafficking; Protein Multimerization; Protein Transport; Receptor mechanisms; Receptors, G-Protein-Coupled - chemistry; Receptors, G-Protein-Coupled - metabolism; Signal Transduction; signaling; trafficking; GPCR; endosome; signaling; trafficking; G protein
• ISSN: 1398-9219; 1600-0854
• DOI: 10.1111/tra.12634

G protein‐coupled receptors (GPCRs) physically connect extracellular information with intracellular signal propagation. Membrane trafficking plays a supportive role by “bookending” signaling events: movement through the secretory pathway delivers GPCRs to the cell surface where receptors can sample the extracellular environment, while endocytosis and endolysosomal membrane trafficking provide a versatile system to titrate cellular signaling potential and maintain homeostatic control. Recent evidence suggests that, in addition to these important effects, GPCR trafficking actively shapes the cellular signaling response by altering the location and timing of specific receptor‐mediated signaling reactions. Here, we review key experimental evidence underlying this expanding view, focused on GPCR signaling mediated through activation of heterotrimeric G proteins located in the cytoplasm. We then discuss lingering and emerging questions regarding the interface between GPCR signaling and trafficking. Membrane trafficking processes modulate G protein‐coupled receptor (GPCR) signaling from the plasma membrane. Emerging evidence suggests that endocytic and biosynthetic membrane compartments, in addition to serving as waystations for cell surface delivery and removal of GPCRs, can also serve as sites of active GPCR signaling. The present review discusses this concept and highlights recent evidence regarding endomembrane GPCR signaling by trimeric G proteins.