CGI-58 Interacts with Perilipin and Is Localized to Lipid Droplets

Abstract

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. 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. Lipid droplets (LDs) 1The abbreviations used are: LDs, lipid droplets; CDS, ChanarinDorfman syndrome; ADRP, adipose differentiation-related protein; PAT, perilipin, ADRP, and TIP47; LDH, lactose dehydrogenase; TAG, triacylglyceride; GFP, green fluorescent protein; CHO, Chinese hamster ovary; HSL, hormone-sensitive lipase; PBS, phosphate-buffered saline; CGI, comparative gene identification; GST, glutathione S-transferase; RT, reverse transcriptase.1The abbreviations used are: LDs, lipid droplets; CDS, ChanarinDorfman syndrome; ADRP, adipose differentiation-related protein; PAT, perilipin, ADRP, and TIP47; LDH, lactose dehydrogenase; TAG, triacylglyceride; GFP, green fluorescent protein; CHO, Chinese hamster ovary; HSL, hormone-sensitive lipase; PBS, phosphate-buffered saline; CGI, comparative gene identification; GST, glutathione S-transferase; RT, reverse transcriptase. are subcellular structures, containing triacylglycerol or cholesterol ester. They are surrounded by a phospholipid monolayer, and function as energy depots (1Murphy D.J. Vance J. Trends Biochem. Sci. 1999; 24: 109-115Abstract Full Text Full Text PDF PubMed Scopus (474) Google Scholar, 2Brown D.A. Curr. Biol. 2001; 11: R446-R449Abstract Full Text Full Text PDF PubMed Scopus (220) Google Scholar, 3Tauchi-Sato K. Ozeki S. Houjou T. Taguchi R. Fujimoto T. J. Biol. Chem. 2002; 277: 44507-44512Abstract Full Text Full Text PDF PubMed Scopus (499) Google Scholar). Moreover, LDs seem to have important roles in lipid trafficking and disorders such as obesity, inflammation, and atherosclerosis (4Murphy D.J. Prog. Lipid Res. 2001; 40: 325-438Crossref PubMed Scopus (748) Google Scholar). Recently, LDs have been characterized as ubiquitous organelles existing in most types of cells and tissues of higher eukaryotes (1Murphy D.J. Vance J. Trends Biochem. Sci. 1999; 24: 109-115Abstract Full Text Full Text PDF PubMed Scopus (474) Google Scholar). However, the mechanism of the biogenesis of LDs is not entirely clear. It is expected that, similar to other organelles, the protein components associated with the membrane surface would regulate the dynamics of LDs. Indeed, a specific set of proteins called the PAT domain family consisting of four members (perilipin, ADRP, TIP47, and S3–12) that share a conserved region at the N terminus (except for S3–12 carrying the region at the C terminus) have been identified as factors associated with the surface of LDs (5Miura S. Gan J.W. Brzostowski J. Parisi M.J. Schultz C.J. Londos C. Oliver B. Kimmel A.R. J. Biol. Chem. 2002; 277: 32253-32257Abstract Full Text Full Text PDF PubMed Scopus (303) Google Scholar). Perilipin is a phosphoprotein that is selectively expressed in adipocytes and steroidogenic cells, involved in cAMP-dependent lipolysis (6Greenberg A.S. Egan J.J. Wek S.A. Moos Jr., M.C. Londos C. Kimmel A.R. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 12035-12039Crossref PubMed Scopus (209) Google Scholar, 7Servetnick D.A. Brasaemle D.L. Gruia-Gray J. Kimmel A.R. Wolff J. Londos C. J. Biol. Chem. 1995; 270: 16970-16973Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar, 8Sztalryd C. Xu G. Dorward H. Tansey J.T. Contreras J.A. Kimmel A.R. Londos C. J. Cell Biol. 2003; 161: 1093-1103Crossref PubMed Scopus (412) Google Scholar). ADRP is ubiquitously expressed in mammalian cells, being involved in lipid uptake, LD formation, milk lipid secretion, and surfactant biosynthesis, and has been used as a marker for diseases involving fat-accumulating cells (9Jiang H.P. Serrero G. Proc. Natl. Acad. Sci. U. S. A. 1992; 89: 7856-7860Crossref PubMed Scopus (225) Google Scholar, 10Brasaemle D.L. Barber T. Wolins N.E. Serrero G. Blanchette-Mackie E.J. Londos C. J. Lipid Res. 1997; 38: 2249-2263Abstract Full Text PDF PubMed Google Scholar, 11Gao J. Serrero G. J. Biol. Chem. 1999; 274: 16825-16830Abstract Full Text Full Text PDF PubMed Scopus (191) Google Scholar, 12McManaman J.L. Palmer C.A. Wright R.M. Neville M.C. J. Physiol. 2002; 545: 567-579Crossref PubMed Scopus (103) Google Scholar, 13Schultz C.J. Torres E. Londos C. Torday J.S. Am. J. Physiol. Lung Cell Mol. Physiol. 2002; 283: L288-L296Crossref PubMed Scopus (101) Google Scholar, 14Corsini E. Viviani B. Zancanella O. Lucchi L. Visioli F. Serrero G. Bartesaghi S. Galli C.L. Marinovich M. J. Investig. Dermatol. 2003; 121: 337-344Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar). S3–12 coats the surface of LDs that are distinct from those surrounded by perilipin in adipocytes (15Wolins N.E. Skinner J.R. Schoenfish M.J. Tzekov A. Bensch K.G. Bickel P.E. J. Biol. Chem. 2003; 278: 37713-37721Abstract Full Text Full Text PDF PubMed Scopus (163) Google Scholar). TIP47 is predicted to exist in LDs or the trans-Golgi network and may regulate intracellular membrane trafficking (16Wolins N.E. Rubin B. Brasaemle D.L. J. Biol. Chem. 2001; 276: 5101-5108Abstract Full Text Full Text PDF PubMed Scopus (241) Google Scholar, 17Diaz E. Pfeffer S.R. Cell. 1998; 93: 433-443Abstract Full Text Full Text PDF PubMed Scopus (321) Google Scholar, 18Krise J.P. Sincock P.M. Orsel J.G. Pfeffer S.R. J. Biol. Chem. 2000; 275: 25188-25193Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar). Despite these functions, the PAT proteins seem to lack any catalytic domains. Hence, it is expected that partners of PAT proteins in the cells help with the functions. Hormone-sensitive lipase (HSL) is a well-characterized partner of perilipin. Perilipin basically blocks the access of HSL to LDs in quiescent adipocytes and thus restricts the lipolytic activity. On the other hand, under conditions of lipolysis, perilipin is multiphosphorylated by cAMP-dependent protein kinase (PKA), and facilitates the access of HSL to LDs, thereby promoting lipolysis (8Sztalryd C. Xu G. Dorward H. Tansey J.T. Contreras J.A. Kimmel A.R. Londos C. J. Cell Biol. 2003; 161: 1093-1103Crossref PubMed Scopus (412) Google Scholar, 19Zhang H.H. Souza S.C. Muliro K.V. Kraemer A.S. J. Biol. Chem. 2003; 278: Full Text Full Text PDF PubMed Scopus Google Scholar). It was that a and increased lipolysis J. A. M.J. L. 2000; PubMed Scopus Google Scholar, J.T. C. Gruia-Gray J. D.L. O. C. Kimmel A.R. Londos C. Proc. Natl. Acad. Sci. U. S. A. 2001; PubMed Scopus Google Scholar). In not being of the of triacylglycerol lipase J. S. T. H. R. Fujimoto A. F. Kraemer O. Proc. Natl. Acad. Sci. U. S. A. 2000; PubMed Scopus Google Scholar, G. R. J.G. M. G. R. J. Biol. Chem. 2002; 277: Full Text Full Text PDF PubMed Scopus Google Scholar). Moreover, an in HSL that the still a of lipolytic H. J. S. F. K. K. S. T. H. S. 2002; PubMed Scopus Google Scholar, S.C. Muliro K.V. L. Kraemer M. A.S. J. Biol. Chem. 2002; 277: Full Text Full Text PDF PubMed Scopus Google Scholar). These that perilipin is a of lipolysis, and other HSL in this the mechanism of lipolysis, it is to the proteins with perilipin. In this study, we found that CGI-58 gene which is as a gene of Chanarin-Dorfman syndrome with perilipin as as ADRP, on the surface of LDs. adipose tissue in a the domain was to yeast two-hybrid for an of perilipin and ADRP were from adipocyte by reverse and a the of the of perilipin to amino acid was was the yeast and was to the were on and by were from the yeast cells and were of containing a similar to which was to be a of was as another the of an for ADRP, the of ADRP was and to as were of the were four the region of four other were similar to Cell cells were as S. M. T. J. Biochem. 2002; PubMed Scopus Google Scholar). cells were with a containing and in the was and cells were in the with of CHO-K1 cells were in of the yeast two-hybrid a CGI-58 the of CGI-58 was by and was to a GFP expression a GFP that has an increased M. C. T. T. T. J. Biol. Chem. 1999; 274: Full Text Full Text PDF PubMed Scopus (23) Google of or mutations of CGI-58 were by or and were by the expression of and were Biochem. PubMed Scopus Google and was in a CGI-58 expressed in was with with and and were from was a from to the was from of cells were with phosphate-buffered and in the adipose tissue was in containing and of the were to to a with the CGI-58 and by of proteins were as an and cells on were with the expression the or mutants of was to the for cells were with for for ADRP or containing for at for perilipin cells were in for and with were with ADRP and perilipin for with PBS, and with for with PBS, cells were and under a the of CGI-58, differentiated 3T3-L1 cells were with and by or CHO-K1 cells were by a as S. T. M. M. T. 1997; PubMed Scopus Google Scholar). were with for and as for ADRP was used for the were as S. M. T. J. Biochem. 2002; PubMed Scopus Google Scholar). was from 3T3-L1 cells an to the was with a in a of and was for at with reverse RT, was with of the as a of the and and were with a and in a proteins were expressed in E. and on Biochem. PubMed Scopus Google Scholar). of the proteins were on perilipin and ADRP were in E. an expression were and by in containing and of of and of the of at were at for at containing a protein was with containing of at the were four with a binding containing and in of the were by and by with an were the binding with perilipin and the the 3T3-L1 was used as the of perilipin. 3T3-L1 cells were with and in binding containing and was by was used as a for the of CGI-58 as a of Perilipin and the yeast two-hybrid we a adipose tissue with perilipin as of perilipin used was to and and the PAT domain and region Gruia-Gray J. D.J. Londos C. Kimmel A.R. 2001; PubMed Scopus Google Scholar, A. A. Brasaemle D.L. J. Biol. Chem. 2003; 278: Full Text Full Text PDF PubMed Scopus Google Scholar). which were for on and were and the of the was identical to CGI-58 and identical to to be a CGI-58 we this to be the It the CGI-58, a protein of amino acid Furthermore, we also a yeast two-hybrid with the ADRP as the CGI-58 was the of four CGI-58 in this the protein other the region to the and amino the region to the C CGI-58 has been as a gene for CDS C. F. F. B. A. R. H. A. J.L. J. M. M. J. Am. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). CDS is a of and is characterized by the intracellular of LDs in types of tissues L. A. PubMed Google Scholar, A. G. E.J. G. J. PubMed Scopus (220) Google Scholar, C. S. F. Dermatol. PubMed Scopus Google Scholar). CGI-58 protein is conserved from to It to a protein family by a M. 1997; PubMed Scopus Google and conserved members of the M. 1997; PubMed Scopus Google Scholar). However, as with the conserved of the that is of the catalytic is by in the region of CGI-58 in In of CGI-58 to Perilipin and the found in yeast two-hybrid we of perilipin or ADRP, the or was to containing or a of the the and perilipin and ADRP to not These in the interaction of CGI-58 with perilipin and ADRP and that the of perilipin and ADRP are not for the Endogenous CGI-58 on the of LDs in 3T3-L1 to the CGI-58, an was the protein expressed in was and used in an of protein from adipose tissue and 3T3-L1 We expected the to with the and CGI-58, on the amino a protein in the adipose tissue at a of which was the of CGI-58 However, the CGI-58 expressed from a mammalian expression was also with this as a of to not we that this CGI-58, and the would be a of the On the of 3T3-L1 we a in the protein expression adipocyte differentiation. the from the cells on we not any with the In for the on of cells the by an in to the for the adipose tissue by another were by not were the Although are another would be the of of Indeed, on a in of of CGI-58 are These that protein expression of CGI-58 is adipocyte differentiation. We the subcellular of CGI-58 in differentiated 3T3-L1 cells by the 3T3-L1 cells were and with the and Endogenous CGI-58 a similar to that of perilipin, that CGI-58 is colocalized with perilipin on the surface of LDs. CGI-58 was also expressed with a in the perilipin was non-differentiated 3T3-L1 cells were for CGI-58, was not CGI-58 in the of the in the of CGI-58 during the of 3T3-L1 in with that of PAT proteins and adipose protein a marker for Cell Biol. 2000; PubMed Scopus Google Scholar). was used as an by the differentiation. was from cells on the to CGI-58 was expressed at a the increased and during the of the This was with that for the CGI-58 protein expression On the other hand, the for perilipin, ADRP, and were with those of a D.L. Barber T. Wolins N.E. Serrero G. Blanchette-Mackie E.J. Londos C. J. Lipid Res. 1997; 38: 2249-2263Abstract Full Text PDF PubMed Google Scholar, Cell Biol. 2000; PubMed Scopus Google of perilipin and were not and with the that these are by the Cell Biol. 2000; PubMed Scopus Google Scholar, A.S. Mol. 1998; PubMed Google Scholar, M. A. T. T. Mol. Cell. Biol. 24: PubMed Scopus Google Scholar). ADRP an in by a from a of D.L. Barber T. Wolins N.E. Serrero G. Blanchette-Mackie E.J. Londos C. J. Lipid Res. 1997; 38: 2249-2263Abstract Full Text PDF PubMed Google Scholar). of S3–12 increased from and to to the in protein (15Wolins N.E. Skinner J.R. Schoenfish M.J. Tzekov A. Bensch K.G. Bickel P.E. J. Biol. Chem. 2003; 278: 37713-37721Abstract Full Text Full Text PDF PubMed Scopus (163) Google Scholar). These that CGI-58 at an of to the in PAT protein CGI-58 is by a mechanism distinct from that of PAT In we that TIP47 was the PAT domain protein in its expression during the and to be to CGI-58 to LDs in 3T3-L1 the mechanisms the of CGI-58 to LDs, we CGI-58 was recruited to LDs similar to the We an expression with GFP to the CGI-58 differentiated 3T3-L1 cells and the of the protein and perilipin GFP-CGI-58 a subcellular with perilipin by the specific Moreover, GFP-CGI-58 was expressed in the non-differentiated cells, a was the being colocalized with ADRP In GFP distributed in the and under set of conditions These that expressed CGI-58 was recruited to LDs and colocalized with perilipin and ADRP. We the of CGI-58 that are for its to LDs. this a of mutants of CGI-58 were as proteins we the CGI-58 mutants were colocalized with perilipin and ADRP, in differentiated and non-differentiated 3T3-L1 cells, perilipin and ADRP, of the amino from the N terminus of CGI-58 its ability to be recruited to the surface of LDs, its on the LDs was in cells other to be recruited to LDs. a was from the C terminus the was These that the region of CGI-58 is for the at the surface of LDs. for CDS, the of CGI-58 to is a of lipid characterized by the of of lipid droplets in with CDS an intracellular of LDs containing triacylglycerol in Recently, CGI-58 mutations were identified as the of CDS C. F. F. B. A. R. H. A. J.L. J. M. M. J. Am. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). distinct mutations were found in the CGI-58 gene of CDS C. F. F. B. A. R. H. A. J.L. J. M. M. J. Am. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, M. M. H. J. Investig. Dermatol. 2003; 121: Full Text Full Text PDF PubMed Scopus Google Scholar). They mutations and amino acid of mutations and to in and a in and an in a and to a of In the mutations of of the region of CGI-58 would be On the other hand, the mutations in a in amino acid at conserved the Hence, these have important roles in the function of the of these we the mutations the CGI-58 to GFP, and the of the CGI-58 proteins in 3T3-L1 cells and in to the a with perilipin or ADRP. these mutations of CGI-58 in On the other hand, the was to the surface of LDs, similar to the with perilipin and ADRP in differentiated and non-differentiated cells, also a to LDs similar to the and not for and with the that of a of the N terminus still the protein to be to LDs in cells We the of CGI-58 mutants in other or to GFP were CHO-K1 cells, which ADRP not perilipin, and the subcellular were to with 3T3-L1 cells, and mutants were recruited to LDs and colocalized with ADRP, and mutants to be were with cells not These that the of mutations of CGI-58 were not to the adipocytes or with the that the of CDS and L. A. PubMed Google Scholar, A. G. E.J. G. J. PubMed Scopus (220) Google Scholar, C. S. F. Dermatol. PubMed Scopus Google Scholar). of CGI-58 the to with examine the mutations found in the CDS the direct interaction of CGI-58 with perilipin, we a the proteins of the and the mutants of CGI-58, and in the to LDs. proteins were with the from the differentiated 3T3-L1 cells containing perilipin, and with that the CGI-58 to perilipin, the and mutants were in the Hence, the CGI-58 mutants to be recruited to LDs to the for perilipin, which in to the We also the binding of ADRP in 3T3-L1 with to the binding not This is with the of the yeast two-hybrid and proteins for this would be that other factors are for the interaction in and are or during the of from the In the study, we identified CGI-58 as a binding partner of perilipin and ADRP a yeast two-hybrid interaction between CGI-58 and perilipin was in a and by an We that CGI-58 is at the surface of LDs in 3T3-L1 cells, with perilipin, and its expression is for adipocyte differentiation. CGI-58 gene was identified a comparative with the as an and the Res. 2000; PubMed Scopus Google Scholar). amino acid of CGI-58 protein is conserved from to its and a region to the found in a family of It is as a member of the on the of its catalytic M. 1997; PubMed Scopus Google Scholar). CGI-58 was identified as a gene of CDS, a characterized by the of of lipid droplets in C. F. F. B. A. R. H. A. J.L. J. M. M. J. Am. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). identified mutations of CGI-58 in CDS C. F. F. B. A. R. H. A. J.L. J. M. M. J. Am. J. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, M. M. H. J. Investig. Dermatol. 2003; 121: Full Text Full Text PDF PubMed Scopus Google Scholar). of would a of were of which and to LDs, indicating that the of CGI-58 is physiologically and its loss may CDS. other was the and thus the via a mechanism other This may a catalytic function of CGI-58, or its interaction with another protein It is also that this the function of perilipin, the LDs are with a specific class of the being perilipin in adipocytes and steroidogenic cells, and ADRP in most other types (6Greenberg A.S. Egan J.J. Wek S.A. Moos Jr., M.C. Londos C. Kimmel A.R. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 12035-12039Crossref PubMed Scopus (209) Google Scholar, 7Servetnick D.A. Brasaemle D.L. Gruia-Gray J. Kimmel A.R. Wolff J. Londos C. J. Biol. Chem. 1995; 270: 16970-16973Abstract Full Text Full Text PDF PubMed Scopus (161) Google Scholar, 10Brasaemle D.L. Barber T. Wolins N.E. Serrero G. Blanchette-Mackie E.J. Londos C. J. Lipid Res. 1997; 38: 2249-2263Abstract Full Text PDF PubMed Google Scholar). They are as a protein family a called the PAT domain (5Miura S. Gan J.W. Brzostowski J. Parisi M.J. Schultz C.J. Londos C. Oliver B. Kimmel A.R. J. Biol. Chem. 2002; 277: 32253-32257Abstract Full Text Full Text PDF PubMed Scopus (303) Google Scholar). function of the PAT domain is not clear. domain not seem to be for to LDs in perilipin or ADRP A. A. S. Brasaemle D.L. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, S. A. J. J. Biol. Chem. 2003; 278: Full Text Full Text PDF PubMed Scopus Google Scholar, J.L. J. D.J. J. Lipid Res. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar, Fujimoto T. Biochem. Res. 2003; PubMed Scopus Google Scholar). Although the region of perilipin was to in storage in LDs, a region containing the region the PAT domain the PAT domain was A. A. S. Brasaemle D.L. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). In the study, we used the of perilipin, containing the PAT domain and the as the for yeast two-hybrid region of ADRP also interaction with the PAT domain and the region of a interaction and CGI-58 is an important partner of this of and protein of CGI-58 were significantly increased the of 3T3-L1 cells, indicating that the expression of the CGI-58 gene is on the perilipin gene A.S. Mol. 1998; PubMed Google Scholar, M. A. T. T. Mol. Cell. Biol. 24: PubMed Scopus Google Scholar, T. M. M. R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, S. C. M. S. M. H. M. T. PubMed Scopus Google are by a of Cell Biol. 2000; PubMed Scopus Google Scholar). we were in the CGI-58 gene is also by in CGI-58 was at an of to that of perilipin or another as as ADRP. Hence, the expression of the CGI-58 gene is by a mechanism distinct from that of of the expression of CGI-58 that of its partners is also of We found CGI-58 to be a binding partner of perilipin and ADRP, with the yeast two-hybrid Moreover, GFP-CGI-58 was colocalized with of these proteins in differentiated and non-differentiated 3T3-L1 cells, However, it is not CGI-58 physiologically with proteins in We would that CGI-58 at with perilipin, which is by the the expression of CGI-58 is of 3T3-L1 that CGI-58 was at the surface of LDs, with perilipin. perilipin in the 3T3-L1 to and the containing the CDS mutations ability for the On the other hand, at we have that ADRP to CGI-58 in the interaction was by the the Although GFP-CGI-58 was colocalized with ADRP in 3T3-L1 and CHO-K1 cells, is still a that CGI-58 is at the surface of LDs with ADRP. the of this study, M. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google the of a on LDs from They that CGI-58 in the LD cells were with that ADRP is ubiquitously perilipin expression is CGI-58 with ADRP in perilipin, it is to the between CGI-58 and ADRP or other PAT proteins in most important to be is the function of CGI-58 on the surface of LDs. CGI-58 has similar to the that the is that it is a lipase the breakdown of or cholesterol ester. However, the in the catalytic to this is by in In the of HSL, another member of the substitution of this with or by the lipase and C. T. M.C. G. PubMed Scopus Google indicating an for this in the perilipin has a in the of in the adipocytes A. A. S. Brasaemle D.L. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google CGI-58, a binding partner of perilipin, may also to the lipolytic on the surface of LDs, in to is to CGI-58 has of CDS by a CGI-58 was in a from a In the of this the of and lipid were that CGI-58 in the lipid of and is thus involved in the pathogenesis of M. M. H. J. Investig. Dermatol. 2003; 121: Full Text Full Text PDF PubMed Scopus Google Scholar). of the of CGI-58 to an of the mechanism of lipid in LDs, and the of diseases involving lipid CDS. We T. C. for the and A. for help in the of this