The Mtm1p carrier and pyridoxal 5′-phosphate cofactor trafficking in yeast mitochondria

Mei M. Whittaker, Aravind Penmatsa, James Whittaker

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Biochemical communication between the cytoplasmic and mitochondrial subsystems of the cell depends on solute carriers in the mitochondrial inner membrane that transport metabolites between the two compartments. We have expressed and purified a yeast mitochondrial carrier protein (Mtm1p, YGR257cp), originally identified as a manganese ion carrier, for biochemical characterization aimed at resolving its function. High affinity, stoichiometric pyridoxal 5′-phosphate (PLP) cofactor binding was characterized by fluorescence titration and calorimetry, and the biochemical effects of mtm1 gene deletion on yeast mitochondria were investigated. The PLP status of the mitochondrial proteome (the mitochondrial 'PLP-ome') was probed by immunoblot analysis of mitochondria isolated from wild type (MTM1+) and knockout (MTM1-) yeast, revealing depletion of mitochondrial PLP in the latter. A direct activity assay of the enzyme catalyzing the first committed step of heme biosynthesis, the PLP-dependent mitochondrial enzyme 5-aminolevulinate synthase, extends these results, providing a specific example of PLP cofactor limitation. Together, these experiments support a role for Mtm1p in mitochondrial PLP trafficking and highlight the link between PLP cofactor transport and iron metabolism, a remarkable illustration of metabolic integration.

Original languageEnglish (US)
Pages (from-to)64-70
Number of pages7
JournalArchives of Biochemistry and Biophysics
Volume568
DOIs
StatePublished - Feb 15 2015

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Mitochondria
Pyridoxal Phosphate
Yeast
Yeasts
5-Aminolevulinate Synthetase
Calorimetry
Fungal Proteins
Mitochondrial Proteins
Biosynthesis
Gene Deletion
Enzyme Assays
Mitochondrial Membranes
Enzymes
Proteome
Manganese
Metabolites
Heme
Titration
Metabolism
Assays

Keywords

  • Heme biosynthesis
  • Iron homeostasis
  • Mitochondrial carrier protein
  • Pyridoxal 5′-phosphate

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

Cite this

The Mtm1p carrier and pyridoxal 5′-phosphate cofactor trafficking in yeast mitochondria. / Whittaker, Mei M.; Penmatsa, Aravind; Whittaker, James.

In: Archives of Biochemistry and Biophysics, Vol. 568, 15.02.2015, p. 64-70.

Research output: Contribution to journalArticle

Whittaker, Mei M. ; Penmatsa, Aravind ; Whittaker, James. / The Mtm1p carrier and pyridoxal 5′-phosphate cofactor trafficking in yeast mitochondria. In: Archives of Biochemistry and Biophysics. 2015 ; Vol. 568. pp. 64-70.
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