title: Distinct cellular pools of perilipin 5 point to roles in lipid trafficking.
abstract: The PAT family of lipid storage droplet proteins comprised five members, each of which has become an established regulator of cellular neutral lipid metabolism. Perilipin 5 (also known as lsdp-5, MLDP, PAT-1, and OXPAT), the most recently discovered member of the family, has been shown to localize to two distinct intracellular pools: the lipid storage droplet (LD), and a poorly characterized cytosolic fraction. We have characterized the denser of these intracellular pools and find that a population of perilipin 5 not associated with large LDs resides in complexes with a discrete density (~1.15 g/ml) and size (~575 kDa). Using immunofluorescence, western blotting of isolated sucrose density fractions, native gradient gel electrophoresis, and co-immunoprecipitation, we have shown that these small (~15 nm), perilipin 5-encoated structures do not contain the PAT protein perilipin 2 (ADRP), but do contain perilipin 3 and several other as of yet uncharacterized proteins. The size and density of these particles as well as their susceptibility to degradation by lipases suggest that like larger LDs, they have a neutral lipid rich core. When treated with oleic acid to promote neutral lipid deposition, cells ectopically expressing perilipin 5 experienced a reorganization of LDs in the cell, resulting in fewer, larger droplets at the expense of smaller ones. Collectively, these data demonstrate that a portion of cytosolic perilipin 5 resides in high density lipid droplet complexes that participate in cellular neutral lipid accumulation.
authors: Department of Chemistry and Biochemistry, Otterbein University, Westerville, OH 43081, USA.
authors: Sadie R
authors: SR
authors: Bartholomew
authors: Erica Hlavin
authors: EH
authors: Bell
authors: Taryn
authors: T
authors: Summerfield
authors: Leslie C
authors: LC
authors: Newman
authors: Erin L
authors: EL
authors: Miller
authors: Brian
authors: B
authors: Patterson
authors: Zach P
authors: ZP
authors: Niday
authors: William E
authors: WE
authors: Ackerman
authors: John T
authors: JT
authors: Tansey
mesh_terms: D000818:Animals; D016466:CHO Cells; D002352:Carrier Proteins / Q000378:metabolism; D002451:Cell Compartmentation; D006224:Cricetinae; D003412:Cricetulus; D003600:Cytosol / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism* / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D009124:Muscle Proteins / Q000378:metabolism* / Q000648:ultrastructure; D009206:Myocardium / Q000378:metabolism; D000070780:Perilipin-2; D000070796:Perilipin-3; D021381:Protein Transport; D015203:Reproducibility of Results
chemical_list: D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; D000070780:Perilipin-2; D000070796:Perilipin-3; C000602983:Plin2 protein, mouse; C523440:Plin3 protein, mouse; C551268:lipid storage droplet protein 5, mouse