CGI-58 interacts with perilipin and is localized to lipid droplets. Possible involvement of CGI-58 mislocalization in Chanarin-Dorfman syndrome.
Lipid droplets (LDs) are a class of ubiquitous cellular organelles that are involved in lipid storage and metabolism. Although the mechanisms of the biogenesis of LDs are still unclear, a set of proteins called the PAT domain family have been characterized as factors associating with LDs. Perilipin, a member of ... this family, is expressed exclusively in the adipose tissue and regulates the breakdown of triacylglycerol in LDs via its phosphorylation. In this study, we used a yeast two-hybrid system to examine the potential function of perilipin. We found direct interaction between perilipin and CGI-58, a deficiency of which correlated with the pathogenesis of Chanarin-Dorfman syndrome (CDS). Endogenous CGI-58 was distributed predominantly on the surface of LDs in differentiated 3T3-L1 cells, and its expression increased during adipocyte differentiation. Overexpressed CGI-58 tagged with GFP gathered at the surface of LDs and colocalized with perilipin. This interaction seems physiologically important because CGI-58 mutants carrying an amino acid substitution identical to that found in CDS lost the ability to be recruited to LDs. These mutations significantly weakened the binding of CGI-58 with perilipin, indicating that the loss of this interaction is involved in the etiology of CDS. Furthermore, we identified CGI-58 as a binding partner of ADRP, another PAT domain protein expressed ubiquitously, by yeast two-hybrid assay. GFP-CGI-58 expressed in non-differentiated 3T3-L1 or CHO-K1 cells was colocalized with ADRP, and the CGI-58 mutants were not recruited to LDs carrying ADRP, indicating that CGI-58 may also cooperate with ADRP.
Mesh Terms:
1-Acylglycerol-3-Phosphate O-Acyltransferase, 3T3-L1 Cells, Adipocytes, Amino Acid Sequence, Animals, Blotting, Western, CHO Cells, Cell Differentiation, Cloning, Molecular, Cricetinae, Cytosol, DNA, Complementary, Esterases, Genetic Vectors, Glutathione Transferase, Humans, Lipase, Lipid Metabolism, Lipids, Membrane Proteins, Mice, Microscopy, Fluorescence, Molecular Sequence Data, Mutation, Phosphoproteins, Phosphorylation, Plasmids, Point Mutation, Protein Binding, Protein Structure, Tertiary, RNA, Messenger, Rats, Recombinant Proteins, Sequence Homology, Amino Acid, Syndrome, Time Factors, Transfection, Triglycerides, Two-Hybrid System Techniques
1-Acylglycerol-3-Phosphate O-Acyltransferase, 3T3-L1 Cells, Adipocytes, Amino Acid Sequence, Animals, Blotting, Western, CHO Cells, Cell Differentiation, Cloning, Molecular, Cricetinae, Cytosol, DNA, Complementary, Esterases, Genetic Vectors, Glutathione Transferase, Humans, Lipase, Lipid Metabolism, Lipids, Membrane Proteins, Mice, Microscopy, Fluorescence, Molecular Sequence Data, Mutation, Phosphoproteins, Phosphorylation, Plasmids, Point Mutation, Protein Binding, Protein Structure, Tertiary, RNA, Messenger, Rats, Recombinant Proteins, Sequence Homology, Amino Acid, Syndrome, Time Factors, Transfection, Triglycerides, Two-Hybrid System Techniques
J. Biol. Chem.
Date: Jul. 16, 2004
PubMed ID: 15136565
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