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Characterization of the novel H82R mutation in CGI‐58 that causes Neutral Lipid Storage Disorder in humans (LB153)
Author(s) -
Hassanien Sarah,
McMahon Derek,
Kurz Daniel,
Shah Dharika,
Dinh Anna,
Brasaemle Dawn
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.lb153
Subject(s) - adipose triglyceride lipase , perilipin , lipid droplet , lipase , triglyceride , chemistry , ectopic expression , microbiology and biotechnology , biology , biochemistry , gene , enzyme , adipose tissue , lipolysis , cholesterol
Comparative gene identification‐58 (CGI‐58) interacts with and co‐activates adipose triglyceride lipase (ATGL). The H82R mutation in human CGI‐58 causes a neutral lipid storage disorder (NLSD) characterized by ichthyosis and excessive triglyceride storage in many types of cells. We studied the comparable H84R mutation in mouse CGI‐58, and H84A mutated CGI‐58, to ask how CGI‐58 function is impaired. The ectopic expression of wild‐type (WT) CGI‐58 in human NLSD fibroblasts reduced excessive triglyceride storage to normal levels, whereas H84R CGI‐58 was significantly less effective. Additionally, neither H84R nor H84A CGI‐58 co‐activated ATGL in an in vitro triglyceride hydrolase assay. A co‐immunoprecipitation assay demonstrated that H84R and H84A CGI‐58 bound ATGL as well as WT CGI‐58. Immunofluorescence microscopy revealed that H84R and H84A CGI‐58 localized to ectopic perilipin 1A on lipid droplets of cultured NIH3T3CARΔ fibroblasts as well as WT CGI‐58. Moreover, the addition of forskolin and isobutylmethylxanthine to the cells triggered the dispersion of all three variants of CGI‐58 from the perilipin scaffold into the cytoplasm. Thus, H84R CGI‐58 shows appropriate subcellular localization in cells expressing perilipin 1A and binds to ATGL, yet does not co‐activate hydrolase activity. Future experiments will explore additional mechanisms for deficient CGI‐58 function. Grant Funding Source : Supported by NIH R01 DK054797.