The human SLC25A33 and SLC25A36 genes of solute carrier family 25 encode two mitochondrial pyrimidine nucleotide transporters

J Biol Chem. 2014 Nov 28;289(48):33137-48. doi: 10.1074/jbc.M114.610808. Epub 2014 Oct 15.

Abstract

The human genome encodes 53 members of the solute carrier family 25 (SLC25), also called the mitochondrial carrier family, many of which have been shown to transport inorganic anions, amino acids, carboxylates, nucleotides, and coenzymes across the inner mitochondrial membrane, thereby connecting cytosolic and matrix functions. Here two members of this family, SLC25A33 and SLC25A36, have been thoroughly characterized biochemically. These proteins were overexpressed in bacteria and reconstituted in phospholipid vesicles. Their transport properties and kinetic parameters demonstrate that SLC25A33 transports uracil, thymine, and cytosine (deoxy)nucleoside di- and triphosphates by an antiport mechanism and SLC25A36 cytosine and uracil (deoxy)nucleoside mono-, di-, and triphosphates by uniport and antiport. Both carriers also transported guanine but not adenine (deoxy)nucleotides. Transport catalyzed by both carriers was saturable and inhibited by mercurial compounds and other inhibitors of mitochondrial carriers to various degrees. In confirmation of their identity (i) SLC25A33 and SLC25A36 were found to be targeted to mitochondria and (ii) the phenotypes of Saccharomyces cerevisiae cells lacking RIM2, the gene encoding the well characterized yeast mitochondrial pyrimidine nucleotide carrier, were overcome by expressing SLC25A33 or SLC25A36 in these cells. The main physiological role of SLC25A33 and SLC25A36 is to import/export pyrimidine nucleotides into and from mitochondria, i.e. to accomplish transport steps essential for mitochondrial DNA and RNA synthesis and breakdown.

Keywords: Liposome; Membrane Transporter Reconstitution; Mitochondria; Mitochondrial Carrier; Mitochondrial Transport; Nucleotide; SLC25 Family; SLC25A33; SLC25A36.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Transport, Active / physiology
  • CHO Cells
  • Cricetinae
  • Cricetulus
  • DNA, Mitochondrial / genetics
  • DNA, Mitochondrial / metabolism
  • Humans
  • Mitochondrial Membrane Transport Proteins / chemistry*
  • Mitochondrial Membrane Transport Proteins / genetics
  • Mitochondrial Membrane Transport Proteins / metabolism*
  • Nucleotide Transport Proteins / chemistry
  • Nucleotide Transport Proteins / genetics
  • Nucleotide Transport Proteins / metabolism
  • Pyrimidine Nucleotides / chemistry*
  • Pyrimidine Nucleotides / metabolism*
  • RNA / genetics
  • RNA / metabolism
  • RNA, Mitochondrial
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Saccharomyces cerevisiae / chemistry
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism

Substances

  • DNA, Mitochondrial
  • Mitochondrial Membrane Transport Proteins
  • Nucleotide Transport Proteins
  • Pyrimidine Nucleotides
  • RIM2 protein, S cerevisiae
  • RNA, Mitochondrial
  • Recombinant Proteins
  • SLC25A33 protein, human
  • Saccharomyces cerevisiae Proteins
  • RNA