title: The Arabidopsis thylakoid ADP/ATP carrier TAAC has an additional role in supplying plastidic phosphoadenosine 5'-phosphosulfate to the cytosol.
abstract: 3'-Phosphoadenosine 5'-phosphosulfate (PAPS) is the high-energy sulfate donor for sulfation reactions. Plants produce some PAPS in the cytosol, but it is predominantly produced in plastids. Accordingly, PAPS has to be provided by plastids to serve as a substrate for sulfotransferase reactions in the cytosol and the Golgi apparatus. We present several lines of evidence that the recently described Arabidopsis thaliana thylakoid ADP/ATP carrier TAAC transports PAPS across the plastid envelope and thus fulfills an additional function of high physiological relevance. Transport studies using the recombinant protein revealed that it favors PAPS, 3'-phosphoadenosine 5'-phosphate, and ATP as substrates; thus, we named it PAPST1. The protein could be detected both in the plastid envelope membrane and in thylakoids, and it is present in plastids of autotrophic and heterotrophic tissues. TAAC/PAPST1 belongs to the mitochondrial carrier family in contrast with the known animal PAPS transporters, which are members of the nucleotide-sugar transporter family. The expression of the PAPST1 gene is regulated by the same MYB transcription factors also regulating the biosynthesis of sulfated secondary metabolites, glucosinolates. Molecular and physiological analyses of papst1 mutant plants indicate that PAPST1 is involved in several aspects of sulfur metabolism, including the biosynthesis of thiols, glucosinolates, and phytosulfokines.
authors.affiliation: Botanical Institute, Cluster of Excellence on Plant Sciences, Cologne Biocenter, University of Cologne, D-50674 Cologne, Germany.
authors.forename: Tamara
authors.initials: T
authors.lastname: Gigolashvili
authors.forename: Melanie
authors.initials: M
authors.lastname: Geier
authors.forename: Natallia
authors.initials: N
authors.lastname: Ashykhmina
authors.forename: Henning
authors.initials: H
authors.lastname: Frerigmann
authors.forename: Sabine
authors.initials: S
authors.lastname: Wulfert
authors.forename: Stephan
authors.initials: S
authors.lastname: Krueger
authors.forename: Sarah G
authors.initials: SG
authors.lastname: Mugford
authors.forename: Stanislav
authors.initials: S
authors.lastname: Kopriva
authors.forename: Ilka
authors.initials: I
authors.lastname: Haferkamp
authors.forename: Ulf-Ingo
authors.initials: UI
authors.lastname: Flügge
mesh_terms: D017920:Antiporters / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001692:Biological Transport; D003600:Cytosol / Q000378:metabolism*; D010724:Phosphoadenosine Phosphosulfate / Q000096:biosynthesis / Q000378:metabolism*; D018087:Plastids / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism*
chemical_list: D017920:Antiporters; D029681:Arabidopsis Proteins; C519172:TAAC protein, Arabidopsis; D010724:Phosphoadenosine Phosphosulfate