Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
SHR Neuro Krebs Kardio Lipid Stoffw Microb
Paar, M; Jüngst, C; Steiner, NA; Magnes, C; Sinner, F; Kolb, D; Lass, A; Zimmermann, R; Zumbusch, A; Kohlwein, SD; Wolinski, H.
Remodeling of lipid droplets during lipolysis and growth in adipocytes.
J Biol Chem. 2012; 287(14):11164-11173
Doi: 10.1074/jbc.M111.316794
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- Führende Autor*innen der Med Uni Graz
- Paar Margret
- Co-Autor*innen der Med Uni Graz
- Kolb Dagmar
- Sinner Frank Michael
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- Abstract:
- Synthesis, storage, and turnover of triacylglycerols (TAGs) in adipocytes are critical cellular processes to maintain lipid and energy homeostasis in mammals. TAGs are stored in metabolically highly dynamic lipid droplets (LDs), which are believed to undergo fragmentation and fusion under lipolytic and lipogenic conditions, respectively. Time lapse fluorescence microscopy showed that stimulation of lipolysis in 3T3-L1 adipocytes causes progressive shrinkage and almost complete degradation of all cellular LDs but without any detectable fragmentation into micro-LDs (mLDs). However, mLDs were rapidly formed after induction of lipolysis in the absence of BSA in the culture medium that acts as a fatty acid scavenger. Moreover, mLD formation was blocked by the acyl-CoA synthetase inhibitor triacsin C, implicating that mLDs are synthesized de novo in response to cellular fatty acid overload. Using label-free coherent anti-Stokes Raman scattering microscopy, we demonstrate that LDs grow by transfer of lipids from one organelle to another. Notably, this lipid transfer between closely associated LDs is not a rapid and spontaneous process but rather occurs over several h and does not appear to require physical interaction over large LD surface areas. These data indicate that LD growth is a highly regulated process leading to the heterogeneous LD size distribution within and between individual cells. Our findings suggest that lipolysis and lipogenesis occur in parallel in a cell to prevent cellular fatty acid overflow. Furthermore, we propose that formation of large LDs requires a yet uncharacterized protein machinery mediating LD interaction and lipid transfer.
- Find related publications in this database (using NLM MeSH Indexing)
- 3T3-L1 Cells -
- Adipocytes - cytology
- Adipocytes - metabolism
- Animals -
- Cell Survival -
- Humans -
- Lipids - chemistry
- Lipolysis -
- Mice -
- Molecular Imaging -
- Stem Cells - cytology
- Surface Properties -
- Time Factors -