Identification of mitochondrial thiamin diphosphate carriers from Arabidopsis and maize

Océane Frelin, Gennaro Agrimi, Valentina L. Laera, Alessandra Castegna, Lynn G L Richardson, Robert T. Mullen, Claudia Lerma-Ortiz, Ferdinando Palmieri, Andrew D. Hanson

Research output: Contribution to journalArticle

Abstract

It is currently held that thiamin is made in chloroplasts and converted in the cytosol to the active cofactor thiamin diphosphate (ThDP), and that mitochondria and plastids import ThDP. The organellar transporters that mediate ThDP import in plants have not been identified. Comparative genomic analysis indicated that two members of the mitochondrial carrier family (MCF) in Arabidopsis (At5g48970 and At3g21390) and two in maize (GRMZM2G118515 and GRMZM2G124911) are related to the ThDP carriers of animals and Saccharomyces cerevisiae. Expression of each of these plant proteins in a S. cerevisiae ThDP carrier (TPC1) null mutant complemented the growth defect on fermentable carbon sources and restored the level of mitochondrial ThDP and the activity of the mitochondrial ThDP-dependent enzyme acetolactate synthase. The plant proteins were targeted to mitochondria as judged by dual import assays with purified pea mitochondria and chloroplasts, and by microscopic analysis of the subcellular localization of green fluorescent protein fusions in transiently transformed tobacco suspension cells. Both maize genes were shown to be expressed throughout the plant, which is consistent with the known ubiquity of mitochondrial ThDP-dependent enzymes. Collectively, these data establish that plants have mitochondrially located MCF carriers for ThDP, and indicate that these carriers are highly evolutionarily conserved. Our data provide a firm basis to propagate the functional annotation of mitochondrial ThDP carriers to other angiosperm genomes.

Original languageEnglish
Pages (from-to)317-326
Number of pages10
JournalFunctional and Integrative Genomics
Volume12
Issue number2
DOIs
Publication statusPublished - Jun 2012

Keywords

  • Functional complementation
  • Membrane transport
  • Mitochondria
  • Thiamin diphosphate carrier
  • Vitamin B1

ASJC Scopus subject areas

  • Genetics

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    Frelin, O., Agrimi, G., Laera, V. L., Castegna, A., Richardson, L. G. L., Mullen, R. T., Lerma-Ortiz, C., Palmieri, F., & Hanson, A. D. (2012). Identification of mitochondrial thiamin diphosphate carriers from Arabidopsis and maize. Functional and Integrative Genomics, 12(2), 317-326. https://doi.org/10.1007/s10142-012-0273-4