title: N-terminus of seed caleosins is essential for lipid droplet sorting but not for lipid accumulation.
abstract: Caleosin, a calcium-binding protein associated with plant lipid droplets, stimulates lipid accumulation when heterologously expressed in Saccharomyces cerevisiae. Accumulated lipids are stored in cytoplasmic lipid droplets that are stabilised by incorporated caleosin. We designed a set of mutants affecting putative crucial sites for caleosin function and association with lipid droplets, i.e. the N-terminus, the EF-hand motif and the proline-knot motif. We investigated the effect of introduced mutations on caleosin capacity to initiate lipid accumulation and on caleosin sorting within cell as well as on its association with lipid droplets. Our results strongly suggest that the N-terminal domain is essential for proper protein sorting and targeting to lipid droplets but not for enhancing lipid accumulation.
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, 78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, 78026 Versailles, France. Electronic address: purkrtova@gmail.com.
authors.forename: Zita
authors.initials: Z
authors.lastname: Purkrtová
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, 78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, 78026 Versailles, France. Electronic address: thierry.chardot@versailles.inra.fr.
authors.forename: Thierry
authors.initials: T
authors.lastname: Chardot
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, 78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, 78026 Versailles, France. Electronic address: marine.froissard@versailles.inra.fr.
authors.forename: Marine
authors.initials: M
authors.lastname: Froissard
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D066292:Lipid Droplets / Q000737:chemistry* / Q000378:metabolism*; D050356:Lipid Metabolism / Q000502:physiology*; D008055:Lipids / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000737:chemistry / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D002135:Calcium-Binding Proteins; D008055:Lipids; D010940:Plant Proteins; D011994:Recombinant Proteins; C402836:caleosin protein, Sesamum indicum
keywords: Caleosin; Lipid accumulation; Lipid droplets; Saccharomyces cerevisiae; Seed; Structure–function study