Human mitochondrial pyruvate carrier 2 as an autonomous membrane transporter

• Published in: Scientific reports 2018-02, Vol.8 (1), p.3510-13, Article 3510
• Main Authors: Nagampalli, Raghavendra Sashi Krishna, Quesñay, José Edwin Neciosup, Adamoski, Douglas, Islam, Zeyaul, Birch, James, Sebinelli, Heitor Gobbi, Girard, Richard Marcel Bruno Moreira, Ascenção, Carolline Fernanda Rodrigues, Fala, Angela Maria, Pauletti, Bianca Alves, Consonni, Sílvio Roberto, de Oliveira, Juliana Ferreira, Silva, Amanda Cristina Teixeira, Franchini, Kleber Gomes, Leme, Adriana Franco Paes, Silber, Ariel Mariano, Ciancaglini, Pietro, Moraes, Isabel, Dias, Sandra Martha Gomes, Ambrosio, Andre Luis Berteli
• Format: Article
• Language: English
• Subjects: 631/45/612/1237; 631/57/2283; 82/80; 82/83; Active transport; Alzheimer's disease; Chromatography; Circular Dichroism; Ectopic expression; Gene Expression Regulation - genetics; Glycolysis; Homeostasis; Humanities and Social Sciences; Humans; Laboratories; Lipid bilayers; Lipid Bilayers - chemistry; Lipids; Localization; Mitochondria; Mitochondrial Membrane Transport Proteins - chemistry; Mitochondrial Membrane Transport Proteins - genetics; Mitochondrial Membranes - chemistry; Mitochondrial Membranes - metabolism; Molecular weight; multidisciplinary; Oxygen consumption; Protein structure; Protein Structure, Secondary - genetics; Proteins; Pyruvic acid; Pyruvic Acid - chemistry; Pyruvic Acid - metabolism; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Science; Science (multidisciplinary); Secondary structure; Yeasts
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-21740-z

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.