CGI-58/ABHD5 is phosphorylated on Ser239 by protein kinase A: control of subcellular localization

J Lipid Res. 2015 Jan;56(1):109-21. doi: 10.1194/jlr.M055004. Epub 2014 Nov 24.


CGI-58/ABHD5 coactivates adipose triglyceride lipase (ATGL). In adipocytes, CGI-58 binds to perilipin 1A on lipid droplets under basal conditions, preventing interaction with ATGL. Upon activation of protein kinase A (PKA), perilipin 1A is phosphorylated and CGI-58 rapidly disperses into the cytoplasm, enabling lipase coactivation. Because the amino acid sequence of murine CGI-58 has a predicted PKA consensus sequence of RKYS(239)S(240), we hypothesized that phosphorylation of CGI-58 is involved in this process. We show that Ser239 of murine CGI-58 is a substrate for PKA using phosphoamino acid analysis, MS, and immuno-blotting approaches to study phosphorylation of recombinant CGI-58 and endogenous CGI-58 of adipose tissue. Phosphorylation of CGI-58 neither increased nor impaired coactivation of ATGL in vitro. Moreover, Ser239 was not required for CGI-58 function to increase triacylglycerol turnover in human neutral lipid storage disorder fibroblasts that lack endogenous CGI-58. Both CGI-58 and S239A/S240A-mutated CGI-58 localized to perilipin 1A-coated lipid droplets in cells. When PKA was activated, WT CGI-58 dispersed into the cytoplasm, whereas substantial S239A/S240A-mutated CGI-58 remained on lipid droplets. Perilipin phosphorylation also contributed to CGI-58 dispersion. PKA-mediated phosphorylation of CGI-58 is required for dispersion of CGI-58 from perilipin 1A-coated lipid droplets, thereby increasing CGI-58 availability for ATGL coactivation.

Keywords: Chanarin Dorfman syndrome; adipocytes; adipose tissue; adipose triglyceride lipase; lipase; lipid droplets; lipolysis; perilipin.

Publication types

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

MeSH terms

  • 1-Acylglycerol-3-Phosphate O-Acyltransferase / chemistry*
  • 1-Acylglycerol-3-Phosphate O-Acyltransferase / metabolism*
  • Adipocytes / cytology
  • Adipocytes / drug effects
  • Adipocytes / metabolism
  • Amino Acid Sequence
  • Animals
  • COS Cells
  • Carrier Proteins / metabolism
  • Chlorocebus aethiops
  • Colforsin / pharmacology
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Gene Expression Regulation / drug effects
  • Humans
  • Intracellular Space / drug effects
  • Intracellular Space / metabolism*
  • Lipase / metabolism
  • Male
  • Mice
  • Molecular Sequence Data
  • Perilipin-1
  • Phosphoproteins / metabolism
  • Phosphorylation / drug effects
  • Protein Binding / drug effects
  • Protein Transport / drug effects
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Serine / metabolism*


  • Carrier Proteins
  • Perilipin-1
  • Phosphoproteins
  • Recombinant Proteins
  • Colforsin
  • Serine
  • 1-Acylglycerol-3-Phosphate O-Acyltransferase
  • ABHD5 protein, human
  • Abhd5 protein, mouse
  • Cyclic AMP-Dependent Protein Kinases
  • Lipase
  • PNPLA2 protein, human
  • PNPLA2 protein, mouse