title: Surface features of the lipid droplet mediate perilipin 2 localization.
abstract: All eukaryotic organisms store excess lipid in intracellular lipid droplets. These dynamic structures are associated with and regulated by numerous proteins. Perilipin 2, an abundant protein on most lipid droplets, promotes neutral lipid accumulation in lipid droplets. However, the mechanism by which perilipin 2 binds to and remains anchored on the lipid droplet surface is unknown. Here we identify features of the lipid droplet surface that influence perilipin 2 localization. We show that perilipin 2 binding to the lipid droplet surface requires both hydrophobic and electrostatic interactions. Reagents that disrupt these interactions also decrease binding. Moreover, perilipin 2 binding does not depend on other lipid droplet-associated proteins but is influenced by the lipid composition of the surface. Perilipin 2 binds to synthetic vesicles composed of dioleoylphosphatidylcholine, a phospholipid with unsaturated acyl chains. Decreasing the temperature of the binding reaction, or introducing phospholipids with saturated acyl chains, decreases binding. We therefore demonstrate a role for surface lipids and acyl chain packing in perilipin 2 binding to lipid droplets. The ability of the lipid droplet phospholipid composition to impact protein binding may link changes in nutrient availability to lipid droplet homeostasis.
authors.affiliation: Department of Biology, St. Olaf College, 1520 St. Olaf Avenue, Northfield, MN 55057, United States; Department of Chemistry, St. Olaf College, 1520 St. Olaf Avenue, Northfield, MN 55057, United States.
authors.forename: Arthur
authors.initials: A
authors.lastname: Sletten
authors.affiliation: Department of Biology, St. Olaf College, 1520 St. Olaf Avenue, Northfield, MN 55057, United States; Department of Chemistry, St. Olaf College, 1520 St. Olaf Avenue, Northfield, MN 55057, United States.
authors.forename: Alison
authors.initials: A
authors.lastname: Seline
authors.affiliation: Department of Biology, St. Olaf College, 1520 St. Olaf Avenue, Northfield, MN 55057, United States; Department of Chemistry, St. Olaf College, 1520 St. Olaf Avenue, Northfield, MN 55057, United States.
authors.forename: Andrew
authors.initials: A
authors.lastname: Rudd
authors.affiliation: Department of Biology, St. Olaf College, 1520 St. Olaf Avenue, Northfield, MN 55057, United States; Department of Chemistry, St. Olaf College, 1520 St. Olaf Avenue, Northfield, MN 55057, United States.
authors.forename: Michelle
authors.initials: M
authors.lastname: Logsdon
authors.affiliation: Department of Biology, St. Olaf College, 1520 St. Olaf Avenue, Northfield, MN 55057, United States; Department of Chemistry, St. Olaf College, 1520 St. Olaf Avenue, Northfield, MN 55057, United States. Electronic address: listenbe@stolaf.edu.
authors.forename: Laura L
authors.initials: LL
authors.lastname: Listenberger
mesh_terms: D001665:Binding Sites; D015870:Gene Expression; D057809:HEK293 Cells; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D066292:Lipid Droplets / Q000737:chemistry* / Q000378:metabolism; D008081:Liposomes / Q000737:chemistry* / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D000070780:Perilipin-2; D010713:Phosphatidylcholines / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D059748:Proteolysis; D055672:Static Electricity
chemical_list: D008081:Liposomes; D008565:Membrane Proteins; D000070780:Perilipin-2; D010713:Phosphatidylcholines; C017251:1,2-oleoylphosphatidylcholine
keywords: Lipid droplet; Perilipin 2; Phospholipid monolayer