Human mitochondrial pyruvate carrier 2 as an autonomous membrane transporter

Raghavendra Sashi Krishna Nagampalli, José Edwin Neciosup Quesnãy, Douglas Adamoski, Zeyaul Islam, James Birch, Heitor Gobbi Sebinelli, Richard Marcel Bruno Moreira Girard, Carolline Fernanda Rodrigues Ascencõ, Angela Maria Fala, Bianca Alves Pauletti, Sílvio Roberto Consonni, Juliana Ferreira De Oliveira, Amanda Cristina Teixeira Silva, Kleber Gomes Franchini, Adriana Franco Paes Leme, Ariel Mariano Silber, Pietro Ciancaglini, Isabel Moraes, Sandra Martha Gomes Dias, Andre Luis Berteli Ambrosio

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17 Citations (Scopus)

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.

Original languageEnglish
Article number3510
Number of pages13
JournalScientific Reports
Volume8
Issue number1
DOIs
Publication statusPublished - 22 Feb 2018
Externally publishedYes

Keywords

  • membrane proteins
  • permeation and transport

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