title: Triacylglycerol mobilization is suppressed by brefeldin A in Chlamydomonas reinhardtii.
abstract: Brefeldin A suppresses vesicle trafficking by inhibiting exchange of GDP for GTP in ADP-ribosylation factor. We report that brefeldin A suppresses mobilization of triacylglycerols in Chlamydomonas reinhardtii, a model organism of green microalgae. Analyses revealed that brefeldin A causes Chlamydomonas to form lipid droplets in which triacylglycerols accumulate in a dose-dependent manner. Pulse labeling experiment using fluorescent fatty acids suggested that brefeldin A inhibits the cells from degrading fatty acids. The experiment also revealed that the cells transiently form novel compartments that accumulate exogenously added fatty acids in the cytoplasm, designated fatty acid-induced microbodies (FAIMs). Brefeldin A up-regulates the formation of FAIMs, whereas nitrogen deprivation that up-regulates triacylglycerol synthesis in Chlamydomonas does not cause the cells to form FAIMs. These results underscore the role of the vesicle trafficking machinery in triacylglycerol metabolism in green microalgae.
authors.affiliation: Department of Biological Sciences, Louisiana State University, 226 Life Sciences Building, Baton Rouge, LA 70803, USA.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Kato
authors.forename: Trung
authors.initials: T
authors.lastname: Dong
authors.forename: Michael
authors.initials: M
authors.lastname: Bailey
authors.forename: Tony
authors.initials: T
authors.lastname: Lum
authors.forename: Drury
authors.initials: D
authors.lastname: Ingram
mesh_terms: D020418:Algal Proteins / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001692:Biological Transport / Q000187:drug effects; D020126:Brefeldin A / Q000494:pharmacology*; D016825:Chlamydomonas reinhardtii / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D004305:Dose-Response Relationship, Drug; D005227:Fatty Acids / Q000378:metabolism / Q000494:pharmacology; D050356:Lipid Metabolism / Q000187:drug effects; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D040901:Proteomics / Q000379:methods; D017386:Sequence Homology, Amino Acid; D013213:Starch / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D020418:Algal Proteins; D005227:Fatty Acids; D011500:Protein Synthesis Inhibitors; D014280:Triglycerides; D020126:Brefeldin A; D013213:Starch
keywords: ADP-ribosylation factor; Lipid droplets; Triacylglycerol mobilization; brefeldin A; microalgae; peroxisome precursor