The PLUTO plastidial nucleobase transporter also transports the thiamin precursor hydroxymethylpyrimidine

Biosci Rep. 2018 Mar 29;38(2):BSR20180048. doi: 10.1042/BSR20180048. Print 2018 Apr 27.

Abstract

In plants, the hydroxymethylpyrimidine (HMP) and thiazole precursors of thiamin are synthesized and coupled together to form thiamin in plastids. Mutants unable to form HMP can be rescued by exogenous HMP, implying the presence of HMP transporters in the plasma membrane and plastids. Analysis of bacterial genomes revealed a transporter gene that is chromosomally clustered with thiamin biosynthesis and salvage genes. Its closest Arabidopsis homolog, the plastidic nucleobase transporter (PLUTO), is co-expressed with several thiamin biosynthetic enzymes. Heterologous expression of PLUTO in Escherichia coli or Saccharomyces cerevisiae increased sensitivity to a toxic HMP analog, and disrupting PLUTO in an HMP-requiring Arabidopsis line reduced root growth at low HMP concentrations. These data implicate PLUTO in plastidial transport and salvage of HMP.

Keywords: Thiamin; hydroxymethylpyrimidine; nucleobase cation symporter 1 family.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Biological Transport, Active / physiology
  • Chloroplast Proteins / genetics
  • Chloroplast Proteins / metabolism*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression
  • Nucleobase Transport Proteins / genetics
  • Nucleobase Transport Proteins / metabolism*
  • Pyrimidines / metabolism*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism

Substances

  • Arabidopsis Proteins
  • Chloroplast Proteins
  • NCS1 protein, Arabidopsis
  • Nucleobase Transport Proteins
  • Pyrimidines
  • Recombinant Proteins