Functionally distinct and selectively phosphorylated GPCR subpopulations co-exist in a single cell

Nat Commun. 2018 Mar 13;9(1):1050. doi: 10.1038/s41467-018-03459-7.

Abstract

G protein-coupled receptors (GPCRs) transduce pleiotropic intracellular signals in a broad range of physiological responses and disease states. Activated GPCRs can undergo agonist-induced phosphorylation by G protein receptor kinases (GRKs) and second messenger-dependent protein kinases such as protein kinase A (PKA). Here, we characterize spatially segregated subpopulations of β2-adrenergic receptor (β2AR) undergoing selective phosphorylation by GRKs or PKA in a single cell. GRKs primarily label monomeric β2ARs that undergo endocytosis, whereas PKA modifies dimeric β2ARs that remain at the cell surface. In hippocampal neurons, PKA-phosphorylated β2ARs are enriched in dendrites, whereas GRK-phosphorylated β2ARs accumulate in soma, being excluded from dendrites in a neuron maturation-dependent manner. Moreover, we show that PKA-phosphorylated β2ARs are necessary to augment the activity of L-type calcium channel. Collectively, these findings provide evidence that functionally distinct subpopulations of this prototypical GPCR exist in a single cell.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Calcium Channels, L-Type / metabolism
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • G-Protein-Coupled Receptor Kinases / metabolism*
  • HEK293 Cells
  • Hippocampus / metabolism
  • Humans
  • Mice
  • Neurons / metabolism
  • Phosphorylation
  • Receptors, Adrenergic, beta-2 / metabolism*
  • Single Molecule Imaging
  • Single-Cell Analysis

Substances

  • Calcium Channels, L-Type
  • Receptors, Adrenergic, beta-2
  • Cyclic AMP-Dependent Protein Kinases
  • G-Protein-Coupled Receptor Kinases