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Review
. 2017 Oct;1862(10 Pt B):1205-1211.
doi: 10.1016/j.bbalip.2017.07.003. Epub 2017 Jul 12.

The collaborative work of droplet assembly

Xiao Chen  1 , Joel M Goodman  2
Affiliations
Review

The collaborative work of droplet assembly

Xiao Chen et al. Biochim Biophys Acta Mol Cell Biol Lipids. 2017 Oct.

Abstract

Three proteins have been implicated in the assembly of cytoplasmic lipid droplets: seipin, FIT2, and perilipin. This review examines the current theories of seipin function as well as the evidence for the involvement of all three proteins in droplet biogenesis, and ends with a proposal of how they collaborate to regulate the formation of droplets. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.

Keywords: FIT2; Lipodystrophy; Perilipin; Pet10; Seipin.

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Conflict of interest statement

Conflicts of Interest

  1. This work is supported by the NIH grant GM084210 and the AHA grant-in-aid 27540010.

  2. I have no financial relationships relevant to my research.

  3. All sources of review for research come from the above grants. My salary is paid only by the University of Texas.

  4. I have not interactions with the sponsor.

  5. I have no patents or copyrights that are relevant.

  6. I have no other relationships relevant to this research or this manuscript.

Figures

Fig. 1
Fig. 1. Function of seipin
In orange, seipin promotes formation of lipid droplets by controling the flow of neutral lipid, phospholipid and certain proteins in the nascent bud. In blue, seipin prevents ER stress, perhaps by minimizing the accumulation of neutral lipid in the ER bilayer. Seipin interacts with SERCA, which may also promote ER homeostasis. Black, pathways by which seipin allows adipogenesis through PPARgamma. This includes promotion of the cytoskeleton through 14-3-3β, controlling GPAT levels and perhaps other lipogenic enzymes to prevent accumulation of a PPARγ antagonist, and prevention of PKA-stimulated lipolysis (perhaps stimulated by a disorganized droplet leaflet), which may allow a fatty acid-related PPAR© agonist to be stored and later available for adipogenesis.
Fig. 2
Fig. 2. Collaboration in Droplet Formation
Seipin promotes the entry of lipids and some droplet proteins into the nascent droplet. FIT2 prevents droplets from budding into the ER lumen. Note that the localization of FIT2 specifically to the ER-droplet junction has yet to be shown. While seipin and FIT2 promote droplet assembly from the ER, Pet10/perilipin permits droplets to bud in a controlled way towards the cytosolic face.
See this image and copyright information in PMC

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