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.
Yamaguchi
Tomohiro
T
Graduate School of Life Science, Himeji Institute of Technology, University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678-1297, Japan.
Omatsu
Naoto
N
Matsushita
Shuhei
S
Osumi
Takashi
T
D051103:1-Acylglycerol-3-Phosphate O-Acyltransferase; D041721:3T3-L1 Cells; D017667:Adipocytes / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D016466:CHO Cells; D002352:Carrier Proteins; D002454:Cell Differentiation; D003001:Cloning, Molecular; D006224:Cricetinae; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004950:Esterases / Q000737:chemistry / Q000378:metabolism*; D005822:Genetic Vectors; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009154:Mutation; D000070778:Perilipin-1; D000070780:Perilipin-2; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D017354:Point Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013577:Syndrome; D013997:Time Factors; D014162:Transfection; D014280:Triglycerides / Q000737:chemistry; D020798:Two-Hybrid System Techniques
D002352:Carrier Proteins; D018076:DNA, Complementary; D008055:Lipids; D008565:Membrane Proteins; C000602982:PLIN2 protein, human; D000070778:Perilipin-1; D000070780:Perilipin-2; D010750:Phosphoproteins; C000602983:Plin2 protein, mouse; C000602984:Plin2 protein, rat; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014280:Triglycerides; D051103:1-Acylglycerol-3-Phosphate O-Acyltransferase; C439972:ABHD5 protein, human; D005982:Glutathione Transferase; D004950:Esterases; D008049:Lipase