1. Human mitochondrial pyruvate carrier 2 as an autonomous membrane transporter
- Author
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Adriana Franco Paes Leme, Carolline Fernanda Rodrigues Ascenção, Richard M. B. M. Girard, Amanda Cristina Teixeira Silva, Pietro Ciancaglini, Kleber G. Franchini, James M. Birch, Raghavendra Sashi Krishna Nagampalli, Zeyaul Islam, José Edwin Neciosup Quesñay, Andre Luis Berteli Ambrosio, Sílvio Roberto Consonni, Bianca Alves Pauletti, Sandra Martha Gomes Dias, Heitor Gobbi Sebinelli, Ariel Mariano Silber, Isabel Moraes, Juliana Ferreira de Oliveira, Douglas Adamoski, and A.M. Fala
- Subjects
Monocarboxylic Acid Transporters ,0301 basic medicine ,Science ,Lipid Bilayers ,Pyruvate transport ,PROTEÍNAS DA MEMBRANA ,Mitochondrial Membrane Transport Proteins ,Protein Structure, Secondary ,Article ,03 medical and health sciences ,0302 clinical medicine ,Protein structure ,Pyruvic Acid ,Humans ,Glycolysis ,Lipid bilayer ,Inner mitochondrial membrane ,Mitochondrial pyruvate carrier 2 ,Multidisciplinary ,biology ,Chemistry ,Circular Dichroism ,Recombinant Proteins ,030104 developmental biology ,Gene Expression Regulation ,Membrane protein ,Chaperone (protein) ,Mitochondrial Membranes ,biology.protein ,Biophysics ,Medicine ,030217 neurology & neurosurgery - Abstract
The active transport of glycolytic pyruvate across the inner mitochondrial membrane is thought to involve two mitochondrial pyruvate carrier subunits, MPC1 and MPC2, assembled as a 150 kDa heterotypic oligomer. Here, the recombinant production of human MPC through a co-expression strategy is first described; however, substantial complex formation was not observed, and predominantly individual subunits were purified. In contrast to MPC1, which co-purifies with a host chaperone, we demonstrated that MPC2 homo-oligomers promote efficient pyruvate transport into proteoliposomes. The derived functional requirements and kinetic features of MPC2 resemble those previously demonstrated for MPC in the literature. Distinctly, chemical inhibition of transport is observed only for a thiazolidinedione derivative. The autonomous transport role for MPC2 is validated in cells when the ectopic expression of human MPC2 in yeast lacking endogenous MPC stimulated growth and increased oxygen consumption. Multiple oligomeric species of MPC2 across mitochondrial isolates, purified protein and artificial lipid bilayers suggest functional high-order complexes. Significant changes in the secondary structure content of MPC2, as probed by synchrotron radiation circular dichroism, further supports the interaction between the protein and ligands. Our results provide the initial framework for the independent role of MPC2 in homeostasis and diseases related to dysregulated pyruvate metabolism.
- Published
- 2018
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