出版社：American Society for Biochemistry and Molecular Biology
摘要：Apolipoprotein A-V (apoA-V) plays a key role in the regulationof triglyceride (TG) metabolism. Given the very low concentrationof apoA-V in plasma, we hypothesized that apoA-V may influenceplasma TG levels by affecting the assembly and/or secretionof apoB-containing lipoproteins. When apoA-V was overexpressedin cultured Hep3B cells, neither the amount of apoB secretednor the density distribution of apoB-containing lipoproteinswas affected. Fluorescence microscopy and cell lysate immunoprecipitationstudies revealed that apoA-V is not associated with apoB intracellularly,yet immunoprecipitation of apoA-V from the cell culture mediumresulted in coprecipitation of apoB. These data suggest thatthe apoA-V association with apoB-containing lipoproteins isa postsecretory event. Confocal fluorescence microscopy revealedthe presence of apoA-V in distinct cellular structures. Basedon Nile Red staining, we identified these structures to be intracellularlipid droplets. These data suggest that apoA-V has a uniqueassociation with cellular lipids and, therefore, may be involvedin the storage or mobilization of intracellular lipids.Supplementary key words Hep3B hepatoma cell line • triglyceride • very low density lipoprotein • immunoprecipitation • confocal fluorescence microscopy • apolipoprotein B
Abbreviations: apoA-V, apolipoprotein A-V; GFP, green fluorescent protein; Met/Cys, methionine/cysteine; OA, oleic acid; TG, triglyceride
