Seeonlineversionforlegendandreferences.1024Cell139,November25,2009©2009ElsevierInc.DOI10.1016/j.cell.2009.11.023SnapShot:LipidDropletsNatalieKrahmer,1YiGuo,2RobertV.Farese,Jr.,2,3andTobiasC.Walther11MaxPlanckInstituteofBiochemistry,Martinsried82152,Germany;2GladstoneInstituteofCardiovascularDiseaseand3UniversityofCalifornia,SanFrancisco,CA94158,USA1024.e1Cell139,November25,2009©2009ElsevierInc.DOI10.1016/j.cell.2009.11.023SnapShot:LipidDropletsNatalieKrahmer,1YiGuo,2RobertV.Farese,Jr.,2,3andTobiasC.Walther11MaxPlanckInstituteofBiochemistry,Martinsried82152,Germany;2GladstoneInstituteofCardiovascularDiseaseand3UniversityofCalifornia,SanFrancisco,CA94158,USAWhatAreLipidDroplets?Lipiddroplets(LDs)areuniversalcellularorganellesthatspecializeinthestorageofneutrallipids,suchassterolestersandtriacylglycerols(seeEssaybyFareseandWalther,thisissue).Assuch,theyprovidethemaincellularreservoirforlipidsofenergystorageandmembranesynthesis,andtheyprotectcellsfromthelipotoxiceffectsofunesterifiedlipids.LDsalsofigureprominentlyinseveraldiseases,includingobesity,type2diabetes,liversteatosis,andatherosclerosis,whicharecharacterizedbytheextensiveaccumulationofLDsindifferentcelltypesandtissues.Additionally,oilsproducedthroughtheengineeringofplantseedsandmicroorganisms(e.g.,forproductionofbiofuels)accumulateinLDs.LDsmayalsoprovideacellularplatformforspecificproteinsandprocesses.Intriguingly,severalimportantintracellularpathogens,suchasthehepatitisCvirusandChlamydiatrachomatis,interactwithLDsduringreplication.ThediameterofLDsvariestremendously(from50nmto200µm)dependingonthecelltype.However,theirstructureappearstobefairlyconsistent,comprisinganeutrallipidcoresurroundedbyaphospholipidmonolayerthatharborssmallamountsoffreecholesterol(seecenterinset).MultipleproteinsapparentlyinteractwiththeLDsurfacethroughdifferentstructuralfeatures.Theseincludelipidanchors(e.g.,Rab18),amphipathicαhelices(e.g.,thoseofperilipinandotherPATproteins),andlonghydrophobichelicesthatintegrateintothephospholipi...
