Insights on the Quest for the Structure-Function Relationship of the Mitochondrial Pyruvate Carrier

Author(s)

Quesnay, Jose Edwin Neciosup ^{[1, 2]} ; Pollock, Naomi L. ^[3] ; Nagampalli, Raghavendra Sashi Krishna ^{[1, 4, 5]} ; Lee, Sarah C. ^[3] ; Balakrishnan, Vijayakumar ^{[6, 7]} ; Dias, Sandra Martha Gomes ^[1] ; Moraes, Isabel ^{[8, 9]} ; Dafforn, Tim R. ^[3] ; Ambrosio, Andre Luis Berteli ^[6]

Affiliation

^[1] Ctr Res Energy & Mat, Brazilian Biosci Natl Lab, BR-13083970 Campinas - Brazil

^[2] Univ Estadual Campinas, Inst Biol, Postgrad Program Biosci & Technol Bioact Prod, BR-13083970 Campinas - Brazil

^[3] Univ Birmingham, Sch Biosci, Birmingham B15 2TT, W Midlands - England

^[4] Monash Univ, Biomed Discovery Inst, Infect & Immun Program, Clayton, Vic 3800 - Australia

^[5] Monash Univ, Biomed Discovery Inst, Dept Biochem & Mol Biol, Clayton, Vic 3800 - Australia

^[6] Univ Sao Paulo, Sao Carlos Inst Phys, BR-13563120 Sao Carlos - Brazil

^[7] Univ Wisconsin, Sch Med & Publ Hlth, Dept Oncol, McArdle Lab Canc Res, Madison, WI 53705 - USA

^[8] Natl Phys Lab, Teddington TW11 0LW, Middx - England

^[9] Diamond Light Source Ltd, Membrane Prot Lab, Harwell Sci & Innovat Campus, Didcot OX11 0DE, Oxon - England

• Document type: Review article
• Source: BIOLOGY-BASEL; v. 9, n. 11 NOV 2020.
• Web of Science Citations: 0

Abstract

Simple Summary The atomic structure of a biological macromolecule determines its function. Discovering how one or more amino acid chains fold and interact to form a protein complex is critical, from understanding the most fundamental cellular processes to developing new therapies. However, this is far from a straightforward task, especially when studying a membrane protein. The functional link between the oligomeric state and complex composition of the proteins involved in the active mitochondrial transport of cytosolic pyruvate is a decades-old question but remains urgent. We present a brief historical review beginning with the identification of the so-called mitochondrial pyruvate carrier (MPC) proteins, followed by a rigorous conceptual analysis of technical approaches in more recent biochemical studies that seek to isolate and reconstitute the functional MPC complex(es) in vitro. We correlate these studies with early kinetic observations and current experimental and computational knowledge to assess their main contributions, identify gaps, resolve ambiguities, and better define the research goal. The molecular identity of the mitochondrial pyruvate carrier (MPC) was presented in 2012, forty years after the active transport of cytosolic pyruvate into the mitochondrial matrix was first demonstrated. An impressive amount of in vivo and in vitro studies has since revealed an unexpected interplay between one, two, or even three protein subunits defining different functional MPC assemblies in a metabolic-specific context. These have clear implications in cell homeostasis and disease, and on the development of future therapies. Despite intensive efforts by different research groups using state-of-the-art computational tools and experimental techniques, MPCs' structure-based mechanism remains elusive. Here, we review the current state of knowledge concerning MPCs' molecular structures by examining both earlier and recent studies and presenting novel data to identify the regulatory, structural, and core transport activities to each of the known MPC subunits. We also discuss the potential application of cryogenic electron microscopy (cryo-EM) studies of MPC reconstituted into nanodiscs of synthetic copolymers for solving human MPC2. (AU)

• FAPESP's process: 14/20673-2 - Biophysical and biochemical studies of the mitochondrial pyruvate carrier (MPC) complex and the glutaminase enzyme bound to novel partners
• Grantee: Andre Luis Berteli Ambrosio
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/11766-5 - Biophysical and biochemical studies of transmembrane mitochondrial proteins and their implication on the tumor metabolism adaptation process
• Grantee: Andre Luis Berteli Ambrosio
• Support Opportunities: Regular Research Grants
• FAPESP's process: 19/02261-2 - Application of synthetic copolymer scaffolds for cryo-electron microscopy studies of the human mitochondrial pyruvate carrier
• Grantee: José Edwin Neciosup Quesñay
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• FAPESP's process: 13/07600-3 - CIBFar - Center for Innovation in Biodiversity and Drug Discovery
• Grantee: Glaucius Oliva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 14/06954-9 - Biophysical studies including X-ray structure determination of the Mitochondrial Pyruvate Carrier (MPC) complex
• Grantee: Raghavendra Sashi Krishna Nagampalli
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 18/00492-4 - Determination of the molecular structure of the human pyruvate carrier subunit 2, MPC2
• Grantee: Vijayakumar Balakrishnan
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/02391-8 - Three-dimensional structure determination of human MPC2 by X-ray crystallography - a mechanistic view into mitochondrial pyruvate transport
• Grantee: Raghavendra Sashi Krishna Nagampalli
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 15/02734-7 - Functional and structural studies of four homologous recombinants of the mitochondrial pyruvate carrier complex
• Grantee: José Edwin Neciosup Quesñay
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)