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

• Published in: Journal of lipid research Vol. 56; no. 1; pp. 109 - 121
• Main Authors: Sahu-Osen, Anita, Montero-Moran, Gabriela, Schittmayer, Matthias, Fritz, Katarina, Dinh, Anna, Chang, Yu-Fang, McMahon, Derek, Boeszoermenyi, Andras, Cornaciu, Irina, Russell, Deanna, Oberer, Monika, Carman, George M., Birner-Gruenberger, Ruth, Brasaemle, Dawn L.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2015; The American Society for Biochemistry and Molecular Biology; Elsevier
• Subjects: 1-Acylglycerol-3-Phosphate O-Acyltransferase - chemistry; 1-Acylglycerol-3-Phosphate O-Acyltransferase - metabolism; adipocytes; Adipocytes - cytology; Adipocytes - drug effects; Adipocytes - metabolism; adipose tissue; adipose triglyceride lipase; Amino Acid Sequence; Animals; Carrier Proteins - metabolism; Chanarin Dorfman syndrome; Chlorocebus aethiops; Colforsin - pharmacology; COS Cells; Cyclic AMP-Dependent Protein Kinases - metabolism; Gene Expression Regulation - drug effects; Humans; Intracellular Space - drug effects; Intracellular Space - metabolism; lipase; Lipase - metabolism; lipid droplets; lipolysis; Male; Mice; Molecular Sequence Data; perilipin; Perilipin-1; Phosphoproteins - metabolism; Phosphorylation - drug effects; Protein Binding - drug effects; Protein Transport - drug effects; Recombinant Proteins - chemistry; Recombinant Proteins - metabolism; Serine - metabolism; perilipin; adipose triglyceride lipase; lipase; adipose tissue; lipid droplets; lipolysis; adipocytes; Chanarin Dorfman syndrome
• ISSN: 0022-2275; 1539-7262
• DOI: 10.1194/jlr.M055004

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 RKYS239S240, 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 immuno­blotting 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.