title: Lipid droplet-associated proteins (LDAPs) are involved in the compartmentalization of lipophilic compounds in plant cells.
abstract: While lipid droplets have traditionally been considered as inert sites for the storage of triacylglycerols and sterol esters, they are now recognized as dynamic and functionally diverse organelles involved in energy homeostasis, lipid signaling, and stress responses. Unlike most other organelles, lipid droplets are delineated by a half-unit membrane whose protein constituents are poorly understood, except in the specialized case of oleosins, which are associated with seed lipid droplets. Recently, we identified a new class of lipid-droplet associated proteins called LDAPs that localize specifically to the lipid droplet surface within plant cells and share extensive sequence similarity with the small rubber particle proteins (SRPPs) found in rubber-accumulating plants. Here, we provide additional evidence for a role of LDAPs in lipid accumulation in oil-rich fruit tissues, and further explore the functional relationships between LDAPs and SRPPs. In addition, we propose that the larger LDAP/SRPP protein family plays important roles in the compartmentalization of lipophilic compounds, including triacylglycerols and polyisoprenoids, into lipid droplets within plant cells. Potential roles in lipid droplet biogenesis and function of these proteins also are discussed.
authors.affiliation: Department of Molecular and Cellular Biology; University of Guelph; Guelph, ON Canada.
authors.forename: Satinder K
authors.initials: SK
authors.lastname: Gidda
authors.forename: Samantha
authors.initials: S
authors.lastname: Watt
authors.affiliation: Department of Biochemistry and Molecular Biology; University of Nevada; Reno, NV USA.
authors.forename: Jillian
authors.initials: J
authors.lastname: Collins-Silva
authors.affiliation: Department of Biological Sciences; East Tennessee State University; Johnson City, TN USA.
authors.forename: Aruna
authors.initials: A
authors.lastname: Kilaru
authors.affiliation: CNRS and University of Bordeaux; UMR5200 LBM; BP81; Villenave d'Ornon cedex, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Arondel
authors.affiliation: USDA-ARS; US Arid-Land Agricultural Research Center; Maricopa, AZ USA.
authors.forename: Olga
authors.initials: O
authors.lastname: Yurchenko
authors.affiliation: Department of Biological Sciences; Center for Plant Lipid Research; University of North Texas; Denton, TX USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Horn
authors.affiliation: Department of Biological Sciences; Center for Plant Lipid Research; University of North Texas; Denton, TX USA.
authors.forename: Christopher N
authors.initials: CN
authors.lastname: James
authors.forename: David
authors.initials: D
authors.lastname: Shintani
authors.affiliation: Department of Plant Biology; Michigan State University; East Lansing, MI USA.
authors.forename: John B
authors.initials: JB
authors.lastname: Ohlrogge
authors.affiliation: Department of Biological Sciences; Center for Plant Lipid Research; University of North Texas; Denton, TX USA.
authors.forename: Kent D
authors.initials: KD
authors.lastname: Chapman
authors.affiliation: Department of Molecular and Cellular Biology; University of Guelph; Guelph, ON Canada.
authors.forename: Robert T
authors.initials: RT
authors.lastname: Mullen
authors.affiliation: USDA-ARS; US Arid-Land Agricultural Research Center; Maricopa, AZ USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Dyer
mesh_terms: D000595:Amino Acid Sequence; D028023:Arecaceae / Q000235:genetics; D002451:Cell Compartmentation; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D066292:Lipid Droplets / Q000378:metabolism*; D008969:Molecular Sequence Data; D059828:Plant Cells / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D020539:Sequence Analysis, Protein
chemical_list: D010940:Plant Proteins; D049452:Green Fluorescent Proteins
keywords: Arabidopsis; Hevea brasiliensis; avocado; guayule; lipid droplet; lipophilic; oil palm; polyisoprenoids; small rubber particle proteins; triacylglycerol