A lipid droplet protein of Nannochloropsis with functions partially analogous to plant oleosins.
As our understanding of the dynamics of lipid droplets (LDs) in animal, plant, and fungal cells is rapidly evolving, still little is known about the formation and turnover of these organelles in microalgae. Yet with the growing importance of algal feedstock for the production of biofuels and high-value lipids, there is a need to understand the mechanisms of LD dynamics in microalgae. Thus, we investigated the proteins associated with LDs of the emerging heterokont model alga Nannochloropsis sp. and discovered an abundant hydrophobic lipid droplet surface protein (LDSP) with unique primary sequence but structural similarities to other LD proteins. LDSP abundance in Nannochloropsis cells closely tracked the amount of triacylglycerols during conditions of oil accumulation and degradation. Functional characterization of LDSP in an Arabidopsis (Arabidopsis thaliana) OLEOSIN1-deficient mutant allowed a separation of its physical and structural properties in its interaction with LDs from its physiological or biochemical activities. Although LDSP presence in Arabidopsis predictably affected LD size, it could not reverse the physiological impact of OLEOSIN deficiency on triacylglycerol hydrolysis during germination.
Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA.
Astrid
A
Vieler
Shane B
SB
Brubaker
Bertrand
B
Vick
Christoph
C
Benning
D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism; D005615:Freezing; D018525:Germination / Q000187:drug effects; D008055:Lipids / Q000737:chemistry*; D008565:Membrane Proteins / Q000378:metabolism; D058086:Microalgae / Q000187:drug effects / Q000378:metabolism*; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000172:deficiency / Q000494:pharmacology; D010940:Plant Proteins / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D012639:Seeds / Q000187:drug effects / Q000378:metabolism; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism
D008055:Lipids; D008565:Membrane Proteins; D010940:Plant Proteins; D014280:Triglycerides; D009584:Nitrogen