Abstract
Lipid droplets (LDs), also called adiposomes, are found in many eukaryotic cells, and are highly upregulated in lipid-storage cells, such as adipocytes. The mechanism by which adiposomes and their component neutral lipids are degraded is an important health issue with the rapidly spreading epidemic of obesity. Recently, a novel triglyceride lipase (adipose triglyceride lipase (ATGL)) that catalyses the initial step in triglyceride hydrolysis in adipocyte LDs was identified. Here, we show that ATGL also functions in non-adipocyte cells, and has an important role in LD degradation in these cells. Overexpression of wild-type ATGL causes a marked decrease in LD size, whereas a catalytically inactive mutant retains the ability to localize to LDs, but is unable to decrease their size. Depletion of ATGL by RNA interference leads to a significant increase in the size of LDs. These results show that ATGL has an important role in LD/adiposome turnover in mammalian cells.
MeSH terms
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Adipocytes / cytology
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Adipocytes / metabolism*
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Amino Acid Sequence
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Animals
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DNA-Binding Proteins / metabolism
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Fluorescent Dyes / metabolism
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HeLa Cells
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Humans
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Intracellular Signaling Peptides and Proteins / metabolism
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Lipase / classification
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Lipase / genetics
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Lipase / metabolism*
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Lipids* / chemistry
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Molecular Sequence Data
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Obesity / metabolism
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Perilipin-3
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Phylogeny
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Pregnancy Proteins / metabolism
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RNA Interference
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RNA, Small Interfering / genetics
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RNA, Small Interfering / metabolism
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism
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Sequence Alignment
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Vesicular Transport Proteins
Substances
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DNA-Binding Proteins
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Fluorescent Dyes
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Intracellular Signaling Peptides and Proteins
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Lipids
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PLIN3 protein, human
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Perilipin-3
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Pregnancy Proteins
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RNA, Small Interfering
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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Vesicular Transport Proteins
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Lipase
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TGL3 protein, S cerevisiae