title: Differential Subplastidial Localization and Turnover of Enzymes Involved in Isoprenoid Biosynthesis in Chloroplasts.
abstract: Plastidial isoprenoids are a diverse group of metabolites with roles in photosynthesis, growth regulation, and interaction with the environment. The methylerythritol 4-phosphate (MEP) pathway produces the metabolic precursors of all types of plastidial isoprenoids. Proteomics studies in Arabidopsis thaliana have shown that all the enzymes of the MEP pathway are localized in the plastid stroma. However, immunoblot analysis of chloroplast subfractions showed that the first two enzymes of the pathway, deoxyxylulose 5-phosphate synthase (DXS) and reductoisomerase (DXR), can also be found in non-stromal fractions. Both transient and stable expression of GFP-tagged DXS and DXR proteins confirmed the presence of the fusion proteins in distinct subplastidial compartments. In particular, DXR-GFP was found to accumulate in relatively large vesicles that could eventually be released from chloroplasts, presumably to be degraded by an autophagy-independent process. Together, we propose that protein-specific mechanisms control the localization and turnover of the first two enzymes of the MEP pathway in Arabidopsis chloroplasts.
authors.affiliation: Program of Plant Metabolism and Metabolic Engineering, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain.
authors.forename: Catalina
authors.initials: C
authors.lastname: Perello
authors.affiliation: Program of Plant Metabolism and Metabolic Engineering, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Llamas
authors.affiliation: Université de Toulouse, CNRS, UMR 5546, BP 42617 Auzeville, 31326 Castanet-Tolosan, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Burlat
authors.affiliation: Program of Plant Metabolism and Metabolic Engineering, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain.
authors.forename: Miriam
authors.initials: M
authors.lastname: Ortiz-Alcaide
authors.affiliation: Program of Plant Metabolism and Metabolic Engineering, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Phillips
authors.affiliation: Program of Plant Metabolism and Metabolic Engineering, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Pulido
authors.affiliation: Program of Plant Metabolism and Metabolic Engineering, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodriguez-Concepcion
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics; D019747:Aldose-Ketose Isomerases / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000201:enzymology* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000201:enzymology* / Q000648:ultrastructure; D017930:Genes, Reporter; D005822:Genetic Vectors / Q000235:genetics; D018515:Plant Leaves / Q000201:enzymology / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D066329:Protein Aggregates; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013347:Subcellular Fractions / Q000201:enzymology; D013729:Terpenes / Q000378:metabolism*; D060431:Thylakoid Membrane Proteins / Q000235:genetics / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism; D014026:Nicotiana; D014166:Transferases / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D066329:Protein Aggregates; D011993:Recombinant Fusion Proteins; D013729:Terpenes; D060431:Thylakoid Membrane Proteins; C114231:1-deoxy-D-xylulose 5-phosphate reductoisomerase; D014166:Transferases; C109461:deoxyxylulose-5-phosphate synthase; D019747:Aldose-Ketose Isomerases