Palmitoylation regulates intracellular trafficking of β2 adrenergic receptor/arrestin/phosphodiesterase 4D complexes in cardiomyocytes

PLoS One. 2012;7(8):e42658. doi: 10.1371/journal.pone.0042658. Epub 2012 Aug 9.

Abstract

β(2) adrenergic receptor (β(2)AR) is a prototypical G-protein coupled receptor that stimulates the classic cAMP-protein kinase A (PKA) signaling pathway. Recent studies indicate that the cAMP-PKA activities are spatiotemporally regulated in part due to dynamic association of β(2)AR with phosphodiesterase 4D (PDE4D), a group of cAMP degradation enzymes. Here, we demonstrate that in cardiomyocytes, palmitoylation of β(2)AR, the covalent acylation of cysteine residue 341, plays a critical role in shaping subcellular cAMP-PKA activities in cardiomyocytes via regulating β(2)AR association with arrestin/PDE4D. Replacing cysteine 341 on β(2)AR with alanine (C341A) leads to an impaired binding to β arrestin 2. Surprisingly, the C341A mutant is able to internalize via an arrestin-independent pathway at saturated concentration of agonist stimulation; the internalization becomes caveolae-dependent and requires dynamin GTPase. However, the impaired binding to β arrestin 2 also leads to an impaired recruitment of PDE4D to the C341A mutant. Thus, the mutant C341A β(2)AR is transported alone from the plasma membrane to the endosome without recruiting PDE4D. This alteration leads to an enhanced cytoplasmic cAMP signal for PKA activation under β(2)AR stimulation. Functionally, Mutation of the C341 residue or inhibition of palmitoylation modification of β(2)AR enhances the receptor-induced PKA activities in the cytoplasm and increases in myocyte contraction rate. Our data reveal a novel function of palmitoylation in shaping subcellular cAMP-PKA signaling in cardiomyocytes via modulating the recruitment of β arrestin 2-PDE4D complexes to the agonist-stimulated β(2)AR.

Publication types

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

MeSH terms

  • Adrenergic beta-2 Receptor Agonists / pharmacology
  • Animals
  • Arrestin / metabolism*
  • Basal Metabolism / drug effects
  • Cyclic AMP / metabolism
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Cyclic Nucleotide Phosphodiesterases, Type 4 / metabolism*
  • Enzyme Activation / drug effects
  • HEK293 Cells
  • Humans
  • Intracellular Space / drug effects
  • Intracellular Space / metabolism*
  • Isoenzymes / metabolism
  • Lipoylation* / drug effects
  • Mice
  • Muscle Contraction / drug effects
  • Myocytes, Cardiac / cytology*
  • Myocytes, Cardiac / drug effects
  • Myocytes, Cardiac / enzymology
  • Myocytes, Cardiac / metabolism*
  • Phosphorylation / drug effects
  • Protein Binding / drug effects
  • Protein Transport / drug effects
  • Receptors, Adrenergic, beta-2 / metabolism*
  • Signal Transduction / drug effects
  • Spatio-Temporal Analysis

Substances

  • Adrenergic beta-2 Receptor Agonists
  • Arrestin
  • Isoenzymes
  • Receptors, Adrenergic, beta-2
  • Cyclic AMP
  • Cyclic AMP-Dependent Protein Kinases
  • Cyclic Nucleotide Phosphodiesterases, Type 4