Lipid droplet-organelle interactions; sharing the fats

Biochim Biophys Acta. 2009 Jun;1791(6):441-7. doi: 10.1016/j.bbalip.2008.07.004. Epub 2008 Jul 30.


Lipid droplets (LDs) are key cellular organelles involved in lipid storage and mobilisation. While the major signalling cascades and many of the regulators of lipolysis have been identified, the cellular interactions involved in lipid mobilisation and release remain largely undefined. In non-adipocytes, LDs are small, mobile and interact with other cellular compartments. In contrast, adipocytes primarily contain very large, immotile LDs. The striking morphological differences between LDs in adipocytes and non-adipocytes suggest that key differences must exist in the manner in which LDs in different cell types interact with other organelles. Recent studies have highlighted the complexity of LD interactions, which can be both homotypic, with each other, and heterotypic, with other organelles. The molecules involved in these interactions are also now emerging, including Rab proteins, key regulators of membrane traffic, and caveolin, an integral membrane protein providing a functional link between the cell surface and LDs. Here we summarise recent insights into the cell biology of the LD particularly focussing on the homotypic and heterotypic interactions in both adipocytes and non-adipocytes. We speculate that these interactions may involve inter-organelle membrane contact sites or a hemi-fusion type mechanism to facilitate lipid transfer.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adipocytes / metabolism
  • Animals
  • Caveolae / metabolism
  • Humans
  • Lipid Metabolism*
  • Lipids / chemistry
  • Membrane Fusion
  • Molecular Conformation
  • Organelle Size
  • Organelles / enzymology
  • Organelles / metabolism*
  • Organelles / ultrastructure
  • Protein Transport
  • Signal Transduction*
  • rab GTP-Binding Proteins / metabolism


  • Lipids
  • rab GTP-Binding Proteins