Packaging of Fat: An Evolving Model of Lipid Droplet Assembly and Expansion

Rutgers Center for Lipid Research and Department of Nutritional Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08901, USA.
Journal of Biological Chemistry (Impact Factor: 4.57). 11/2011; 287(4):2273-9. DOI: 10.1074/jbc.R111.309088
Source: PubMed


Lipid droplets (LDs) are organelles found in most types of cells in the tissues of vertebrates, invertebrates, and plants, as well as in bacteria and yeast. They differ from other organelles in binding a unique complement of proteins and lacking an aqueous core but share aspects of protein trafficking with secretory membrane compartments. In this minireview, we focus on recent evidence supporting an endoplasmic reticulum origin for LD formation and discuss recent findings regarding LD maturation and fusion.

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    • "In the late phase of adipocyte differentiation, PLIN2 expression gradually declines and is replaced by PLIN1 in mature adipocytes [101]. PLIN2 primarily localizes to the surface of LDs as do PLIN1, whereas PLIN3 is stable in the cytoplasm and relocates to nascent LDs upon increased TAG synthesis [102]. "
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    ABSTRACT: Cytosolic lipid droplets are dynamic lipid-storage organelles that play a crucial role as reservoirs of metabolic energy and membrane precursors. These organelles are present in virtually all cell types, from unicellular to pluricellular organisms. Despite similar structural organization, lipid droplets are heterogeneous in morphology, distribution and composition. The protein repertoire associated to lipid droplet controls the organelle dynamics. Distinct structural lipid droplet proteins are associated to specific lipolytic pathways. The role of these structural lipid droplet-associated proteins in the control of lipid droplet degradation and lipid store mobilization is discussed. The control of the strictly-regulated lipolysis in lipid-storing tissues is compared between mammals and plants. Differences in the cellular regulation of lipolysis between lipid-storing tissues and other cell types are also discussed. Copyright © 2015. Published by Elsevier B.V.
    Biochimie 07/2015; DOI:10.1016/j.biochi.2015.07.010 · 2.96 Impact Factor
    • "Each neutral lipid core of a LD has a coat consisting of a phospholipid monolayer, with phosphatidylcholine providing the quantitatively major component. Other polar lipids contribute, such as cholesterol and nonesterified fatty acids (Robenek et al., 2011; Brasaemle and Wolins, 2012). The amphipathic monolayer prevents multilocular LDs from coalescing into very large LDs and provides docking stations for proteins. "

    The Retinoids, 06/2015: pages 57-73; , ISBN: 9781118627983
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    • "3. Regulation of Lipolysis via the Coordinated Action of Lipases and Cofactors The discovery of perilipin 1 provided proof of cofactors which exist in the cytoplasm and on the lipid droplet surface [34]. Perilipin 1 is the founding member of the perilipin, adipophilin, and TIP47 family (referred to as the PAT/perilipin family protein) of lipid droplet-coated proteins [35] and is expressed mostly in white adipose tissue, where it coats lipid droplets, and in steroidogenic tissue [36]. Perilipin 1 has as many as six phosphorylation sites (Ser81, Ser222, Ser276, Ser433, Ser492, and Ser517) in adipocytes by PKA [37] [38] [39] [40]. "
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    ABSTRACT: Physical exercise accelerates the mobilization of free fatty acids from white adipocytes to provide fuel for energy. This happens in several tissues and helps to regulate a whole-body state of metabolism. Under these conditions, the hydrolysis of triacylglycerol (TG) that is found in white adipocytes is known to be augmented via the activation of these lipolytic events, which is referred to as the “lipolytic cascade.” Indeed, evidence has shown that the lipolytic responses in white adipocytes are upregulated by continuous exercise training (ET) through the adaptive changes in molecules that constitute the lipolytic cascade. During the past few decades, many lipolysis-related molecules have been identified. Of note, the discovery of a new lipase, known as adipose triglyceride lipase, has redefined the existing concepts of the hormone-sensitive lipase-dependent hydrolysis of TG in white adipocytes. This review outlines the alterations in the lipolytic molecules of white adipocytes that result from ET, which includes the molecular regulation of TG lipases through the lipolytic cascade.
    Journal of obesity 05/2015; 2015:1-10. DOI:10.1155/2015/473430
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