1. National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China 2. University of Chinese Academy of Sciences, Beijing 100049, China
The lipid droplet (LD) is a unique multi-functional organelle that contains a neutral lipid core covered with a phospholipid monolayer membrane. The LDs have been found in almost all organisms from bacteria to humans with similar shape. Several conserved functions of LDs have been revealed by recent studies, including lipid metabolism and trafficking, as well as nucleic acid binding and protection. We summarized these findings and proposed a hypothesis that the LD is a conserved organelle.
BarbosaAD, SiniossoglouS (2017) Function of lipid dropletorganelle interactions in lipid homeostasis. Biochimica et Biophysica Acta. https://doi.org/10.1016/j.bbamcr.2017.04.001
3
BartzR, ZehmerJK, ZhuM, ChenY, SerreroG, ZhaoY, LiuP (2007) Dynamic activity of lipid droplets: protein phosphorylation and GTP-mediated protein translocation. J Proteome Res6:3256–3265 https://doi.org/10.1021/pr070158j
4
BobikTA, LehmanBP, YeatesTO (2015) Bacterial microcompartments: widespread prokaryotic organelles for isolation and optimization of metabolic pathways. Mol Microbiol98:193–207 https://doi.org/10.1111/mmi.13117
5
CaoH, GerholdK, MayersJR, WiestMM, WatkinsSM, HotamisligilGS (2008) Identification of a lipokine, a lipid hormone linking adipose tissue to systemic metabolism. Cell134:933–944 https://doi.org/10.1016/j.cell.2008.07.048
6
CermelliS, GuoY, GrossSP, WelteMA (2006) The lipid-droplet proteome reveals that droplets are a protein-storage depot. Curr Biol16:1783–1795 https://doi.org/10.1016/j.cub.2006.07.062
DingY, YangL, ZhangS, WangY, DuY, PuJ, PengG, ChenY, ZhangH, YuJ, HangH, WuP, YangF, YangH, SteinbuchelA, LiuP (2012) Identification of the major functional proteins of prokaryotic lipid droplets. J Lipid Res53:399–411 https://doi.org/10.1194/jlr.M021899
13
DvorakAM (2005) Mast cell secretory granules and lipid bodies contain the necessary machinery important for the in situ synthesis of proteins. Chem Immunol Allergy85:252–315 https://doi.org/10.1159/000086520
14
DvorakAM, MorganES, WellerPF (2003) RNA is closely associated with human mast cell lipid bodies. Histol Histopathol18:943–968
15
EdwardsMR, BernsDS, GhiorseWC, HoltSC (1968) Ultrastructure of the thermophilic blue-green alga, synechococcus lividus copeland(1). J Phycol4:283–298 https://doi.org/10.1111/j.1529-8817.1968.tb04697.x
FichesGN, EyreNS, AloiaAL, Van Der HoekK, Betz-StableinB, LucianiF, ChopraA, BeardMR (2016) HCV RNA traffic and association with NS5A in living cells. Virology493:60–74 https://doi.org/10.1016/j.virol.2016.02.016
18
GentzschJ, BrohmC, SteinmannE, FrieslandM, MenzelN, VieyresG, PerinPM, FrentzenA, KaderaliL, PietschmannT (2013) Hepatitis C virus p7 is critical for capsid assembly and envelopment. PLoS Pathogens9:e1003355 https://doi.org/10.1371/journal.ppat.1003355
19
HanischJ, WaltermannM, RobenekH, SteinbuchelA (2006) Eukaryotic lipid body proteins in oleogenous actinomycetes and their targeting to intracellular triacylglycerol inclusions: Impact on models of lipid body biogenesis. Appl Environ Microbiol72:6743–6750 https://doi.org/10.1128/AEM.00584-06
20
KimmelAR, BrasaemleDL, McAndrews-HillM, SztalrydC, LondosC (2010) Adoption of PERILIPIN as a unifying nomenclature for the mammalian PAT-family of intracellular lipid storage droplet proteins. J Lipid Res51:468–471 https://doi.org/10.1194/jlr.R000034
21
LayerenzaJP, GonzalezP, Garcia de BravoMM, PoloMP, SistiMS, Ves-LosadaA (1831) Nuclear lipid droplets: a novel nuclear domain. Biochem Biophys Acta2013:327–340
22
LiZ, ThielK, ThulPJ, BellerM, KuhnleinRP, WelteMA (2012) Lipid droplets control the maternal histone supply of Drosophila embryos. Curr Biol22:2104–2113 https://doi.org/10.1016/j.cub.2012.09.018
23
LiZ, JohnsonMR, KeZ, ChenL, WelteMA (2014) Drosophila lipid droplets buffer the H2Av supply to protect early embryonic development. Curr Biol24:1485–1491 https://doi.org/10.1016/j.cub.2014.05.022
24
LiL, WalshRM, WaghV, JamesMF, BeauchampRL, ChangYS, GusellaJF, HochedlingerK, RameshV (2015) Mediator subunit Med28 is essential for mouse peri-implantation development and pluripotency. PLoS ONE10:e0140192 https://doi.org/10.1371/journal.pone.0140192
25
LiuP, YingY, ZhaoY, MundyDI, ZhuM, AndersonRG (2004) Chinese hamster ovary K2 cell lipid droplets appear to be metabolic organelles involved in membrane traffic. J Biol Chem279:3787–3792 https://doi.org/10.1074/jbc.M311945200
26
LiuZ, LiX, GeQ, DingM, HuangX (2014) A lipid droplet-associated GFP reporter-based screen identifies new fat storage regulators in C. elegans. J Genet Genomics41:305–313 https://doi.org/10.1016/j.jgg.2014.03.002
MartinS, PartonRG (2006) Lipid droplets: a unified view of a dynamic organelle. Nat Rev Mol Cell Biol7:373–378 https://doi.org/10.1038/nrm1912
29
MiyanariY, AtsuzawaK, UsudaN, WatashiK, HishikiT, ZayasM, BartenschlagerR, WakitaT, HijikataM, ShimotohnoK (2007) The lipid droplet is an important organelle for hepatitis C virus production. Nat Cell Biol9:1089–1097 https://doi.org/10.1038/ncb1631
OhsakiY, KawaiT, YoshikawaY, ChengJ, JokitaloE, FujimotoT (2016) PML isoform II plays a critical role in nuclear lipid droplet formation. J Cell Biol212:29–38 https://doi.org/10.1083/jcb.201507122
35
O’MahonyF, WroblewskiK, O’ByrneSM, JiangH, ClerkinK, BenhammouJ, BlanerWS, BeavenSW (2015) Liver X receptors balance lipid stores in hepatic stellate cells through Rab18, a retinoid responsive lipid droplet protein. Hepatology62:615–626 https://doi.org/10.1002/hep.27645
36
PeramunaA, SummersML (2014) Composition and occurrence of lipid droplets in the cyanobacterium Nostoc punctiforme. Arch Microbiol196:881–890 https://doi.org/10.1007/s00203-014-1027-6
37
PloeghHL (2007) A lipid-based model for the creation of an escape hatch from the endoplasmic reticulum. Nature448:435–438 https://doi.org/10.1038/nature06004
SatoS, FukasawaM, YamakawaY, NatsumeT, SuzukiT, ShojiI, AizakiH, MiyamuraT, NishijimaM (2006) Proteomic profiling of lipid droplet proteins in hepatoma cell lines expressing hepatitis C virus core protein. J Biochem139:921–930 https://doi.org/10.1093/jb/mvj104
40
ShiST, PolyakSJ, TuH, TaylorDR, GretchDR, LaiMMC (2002) Hepatitis C virus NS5A colocalizes with the core protein on lipid droplets and interacts with apolipoproteins. Virology292:198–210 https://doi.org/10.1006/viro.2001.1225
41
UenoM, ShenWJ, PatelS, GreenbergAS, AzharS, KraemerFB (2012) Fat-specific protein 27 modulates nuclear factor of activated T cells 5 and the cellular response to stress. J Lipid Res54:734–743 https://doi.org/10.1194/jlr.M033365
42
Van de MeeneAM, Hohmann-MarriottMF, VermaasWF, RobersonRW (2006) The three-dimensional structure of the cyanobacterium Synechocystis sp. PCC 6803. Arch Microbiol184:259–270 https://doi.org/10.1007/s00203-005-0027-y
43
WaltermannM, SteinbuchelA (2005) Neutral lipid bodies in prokaryotes: recent insights into structure, formation, and relationship to eukaryotic lipid depots. J Bacteriol187:3607–3619 https://doi.org/10.1128/JB.187.11.3607-3619.2005
44
WaltermannM, HinzA, RobenekH, TroyerD, ReicheltR, MalkusU, GallaHJ, KalscheuerR, StovekenT, von LandenbergP, SteinbuchelA (2005) Mechanism of lipid-body formation in prokaryotes: how bacteria fatten up. Mol Microbiol55:750–763 https://doi.org/10.1111/j.1365-2958.2004.04441.x
45
WanHC, MeloRC, JinZ, DvorakAM, WellerPF (2007) Roles and origins of leukocyte lipid bodies: proteomic and ultrastructural studies. FASEB J21:167–178 https://doi.org/10.1096/fj.06-6711com
46
WangL, WangY, LiangY, LiJ, LiuY, ZhangJ, ZhangA, FuJ, JiangG (2013) Specific accumulation of lipid droplets in hepatocyte nuclei of PFOA-exposed BALB/c mice. Sci Rep3:2174 https://doi.org/10.1038/srep02174
47
WangY, ZhouXM, MaX, DuY, ZhengL, LiuP (2016) Construction of nano-droplet/adiposome and artificial lipid droplets. ACS Nano10:3312–3322 https://doi.org/10.1021/acsnano.5b06852
WolkCP (1973) Physiology and cytological chemistry blue-green algae. Bacteriol Rev37:32–101
50
YangL, DingYF, ChenY, ZhangSY, HuoCX, WangY, YuJH, ZhangP, NaHM, ZhangHN, MaYB, LiuPS (2012) The proteomics of lipid droplets: structure, dynamics, and functions of the organelle conserved from bacteria to humans. J Lipid Res53:1245–1253 https://doi.org/10.1194/jlr.R024117
51
ZhangP, NaH, LiuZ, ZhangS, XueP, ChenY, PuJ, PengG, HuangX, YangF, XieZ, XuT, XuP, OuG, ZhangSO, LiuP (2012) Proteomic study and marker protein identification of Caenorhabditis elegans lipid droplets. Mol Cell Proteomics11:317–328 https://doi.org/10.1074/mcp.M111.016345
52
ZhangC, YangL, DingY, WangY, LanL, MaQ, ChiX, WeiP, ZhaoY, SteinbuchelA, ZhangH, LiuP (2017) Bacterial lipid droplets bind to DNA via an intermediary protein that enhances survival under stress. Nat Commun8:15979 https://doi.org/10.1038/ncomms15979