出版社：American Society for Biochemistry and Molecular Biology
摘要：Comparative Gene Identification-58 (CGI-58) is a member of the/ß-hydrolase family of proteins. Mutations in thehuman CGI-58 gene are associated with Chanarin-Dorfman syndrome,a rare autosomal recessive genetic disease in which excessivetriglyceride (TG) accumulation occurs in multiple tissues. Inthis study, we investigated the role of CGI-58 in cellular lipidmetabolism in several cell models and discovered a role forCGI-58 in promoting the packaging of cytoplasmic TG into secretedlipoprotein particles in hepatoma cells. Using both gain-of-functionand loss-of-function approaches, we demonstrate that CGI-58facilitates the depletion of cellular TG stores without alteringcellular cholesterol or phospholipid accumulation. This depletionof cellular TG is attributable solely to augmented hydrolysis,whereas TG synthesis was not affected by CGI-58. Furthermore,CGI-58-mediated TG hydrolysis can be completely inhibited bythe known lipase inhibitors diethylumbelliferyl phosphate anddiethyl-p-nitrophenyl phosphate, but not by p-chloro-mercuribenzoate.Intriguingly, CGI-58-driven TG hydrolysis was coupled to increasesin both fatty acid oxidation and secretion of TG. Collectively,this study reveals a role for CGI-58 in coupling lipolytic degradationof cytoplasmic TG to oxidation and packaging into TG-rich lipoproteinsfor secretion in hepatoma cells.Supplementary key words Comparative Gene Identification-58 • triglyceride hydrolysis • lipolysis
Abbreviations: ADRP, adipose differentiation-related protein; apoB, apolipoprotein B; ATGL, adipose triglyceride lipase; CDS, Chanarin-Dorfman syndrome; CE, cholesteryl ester; CGI-58, Comparative Gene Identification-58; DEUP, diethylumbelliferyl phosphate; E-600, diethyl-p-nitrophenyl phosphate; EGFP, enhanced green fluorescent protein; ER, endoplasmic reticulum; IDL, intermediate density lipoprotein; iPLA2, calcium-independent phospholipase A2; LD, lipid droplet; MTP, microsomal triglyceride transfer protein; PCMB, p-chloro-mercuribenzoate; PL, phospholipid; siRNA, short interfering RNA; TG, triglyceride
/ß-hydrolase family of proteins. Mutations in the human CGI-58 gene are associated with Chanarin-Dorfman syndrome, a rare autosomal recessive genetic disease in which excessive triglyceride (TG) accumulation occurs in multiple tissues. In this study, we investigated the role of CGI-58 in cellular lipid metabolism in several cell models and discovered a role for CGI-58 in promoting the packaging of cytoplasmic TG into secreted lipoprotein particles in hepatoma cells. Using both gain-of-function and loss-of-function approaches, we demonstrate that CGI-58 facilitates the depletion of cellular TG stores without altering cellular cholesterol or phospholipid accumulation. This depletion of cellular TG is attributable solely to augmented hydrolysis, whereas TG synthesis was not affected by CGI-58. Furthermore, CGI-58-mediated TG hydrolysis can be completely inhibited by the known lipase inhibitors diethylumbelliferyl phosphate and diethyl-p-nitrophenyl phosphate, but not by p-chloro-mercuribenzoate. Intriguingly, CGI-58-driven TG hydrolysis was coupled to increases in both fatty acid oxidation and secretion of TG. Collectively, this study reveals a role for CGI-58 in coupling lipolytic degradation of cytoplasmic TG to oxidation and packaging into TG-rich lipoproteins for secretion in hepatoma cells.
Supplementary key words Comparative Gene Identification-58 • triglyceride hydrolysis • lipolysis
Abbreviations: ADRP, adipose differentiation-related protein; apoB, apolipoprotein B; ATGL, adipose triglyceride lipase; CDS, Chanarin-Dorfman syndrome; CE, cholesteryl ester; CGI-58, Comparative Gene Identification-58; DEUP, diethylumbelliferyl phosphate; E-600, diethyl-p-nitrophenyl phosphate; EGFP, enhanced green fluorescent protein; ER, endoplasmic reticulum; IDL, intermediate density lipoprotein; iPLA2
, calcium-independent phospholipase A2
