title: Regulation of mitochondrial pyruvate uptake by alternative pyruvate carrier complexes.
abstract: At the pyruvate branch point, the fermentative and oxidative metabolic routes diverge. Pyruvate can be transformed either into lactate in mammalian cells or into ethanol in yeast, or transported into mitochondria to fuel ATP production by oxidative phosphorylation. The recently discovered mitochondrial pyruvate carrier (MPC), encoded by MPC1, MPC2, and MPC3 in yeast, is required for uptake of pyruvate into the organelle. Here, we show that while expression of Mpc1 is not dependent on the carbon source, expression of Mpc2 and Mpc3 is specific to fermentative or respiratory conditions, respectively. This gives rise to two alternative carrier complexes that we have termed MPCFERM and MPCOX. By constitutively expressing the two alternative complexes in yeast deleted for all three endogenous genes, we show that MPCOX has a higher transport activity than MPCFERM, which is dependent on the C-terminus of Mpc3. We propose that the alternative MPC subunit expression in yeast provides a way of adapting cellular metabolism to the nutrient availability.
authors: Department of Cell Biology, University of Geneva, Genève, Switzerland.
authors: Tom
authors: T
authors: Bender
authors: Department of Cell Biology, University of Geneva, Genève, Switzerland.
authors: Gabrielle
authors: G
authors: Pena
authors: Department of Cell Biology, University of Geneva, Genève, Switzerland jean-claude.martinou@unige.ch.
authors: Jean-Claude
authors: JC
authors: Martinou
mesh_terms: D027321:Anion Transport Proteins / Q000096:biosynthesis* / Q000235:genetics; D001693:Biological Transport, Active / Q000502:physiology; D015966:Gene Expression Regulation, Fungal / Q000502:physiology; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D046912:Multiprotein Complexes / Q000096:biosynthesis / Q000235:genetics; D010101:Oxygen Consumption / Q000502:physiology; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000096:biosynthesis* / Q000235:genetics; D019289:Pyruvic Acid / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D027321:Anion Transport Proteins; C573717:FMP43 protein, S cerevisiae; C573716:MPC2 protein, S cerevisiae; D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D046912:Multiprotein Complexes; D029701:Saccharomyces cerevisiae Proteins; D019289:Pyruvic Acid; C413542:GPI13 protein, S cerevisiae; D017853:Phosphotransferases (Alcohol Group Acceptor)
keywords: metabolism; mitochondria; mitochondrial pyruvate carrier; pyruvate branch point