Functional and structural studies of four homologous recombinants of the mitochondrial pyruvate carrier complex

• Grant number: 15/02734-7
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: August 01, 2015
• End date: February 10, 2020
• Field of knowledge: Biological Sciences - Biochemistry - Chemistry of Macromolecules
• Principal Investigator: Andre Luis Berteli Ambrosio
• Grantee: José Edwin Neciosup Quesñay
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated scholarship(s): 19/02261-2 - Application of synthetic copolymer scaffolds for cryo-electron microscopy studies of the human mitochondrial pyruvate carrier, BE.EP.DD

Abstract

Pyruvate is the end product of cytosolic glycolysis and has a number of possible intracellular fates, the major one being mitochondrial transport. Pyruvate transport across the mitochondrial membrane is a critical step in carbohydrate, amino acid, and lipid metabolism. While pyruvate has been known to cross the mitochondrial membrane over a long period of time, it is only recently that proteins necessary for this activity have been identified. In this perspective, two Internal Mitochondrial Membrane (IMM) proteins, named MPC1 and MPC2, were identified as the proteins essential for the transport of pyruvate in yeast (S. cerevisiae), Drosophila and humans. These proteins were believed to possess three transmembrane helices with each subunits weighing 15 kDa. However, according to the data reported, the functional complex (MPC1 and MPC2) is believed to have a molecular weight of 150 kDa indicating the possibility of a decamer formation. Although the proteins involved in the pyruvate transport have been identified, questions such as what are the role of the individual proteins (MPC 1 and MPC 2) in the complex, what is the stoichiometry between them, and what are the molecular determinants of the pyruvate transport have not been addressed so far. In order to answer these questions, the present project proposes the biophysical characterization of the complex. Considering that MPC is a transmembrane complex, one would expect serious difficulties in the expression and purification of the complex. For this project, we choose to work with MPC complex homologues from chicken (Gallus gallus), nematode (Caenorhabditis elegans), plant (Arabidopsis thaliana) and sea anemone (Nematostella vectensis). To overcome difficulties, yeast expression will be employed as the choice of the expression system as it could help with the folding and stability of the MPC complex. In addition to this, determination of the detergent or mixture of detergents, which will effectively break the organization of the plasma membrane, without compromising the tertiary structure of the protein, also needed to be determined. In this regard, during the year of 2013 our laboratory generated a set of promising preliminary results that fully support the feasibility of this proposal. Biophysical and biochemical studies (dynamic light scattering, differential scanning calorimetry, mass spectrometry, isothermal titration calorimetry, surface plasmonic resonance, and negative staining and/or cryo-electron microscopy) are predicted and will be carried out on the purified MPC complex, in order to determine its exact molecular weight and stoichiometry and overall architecture. The proposed project once successfully completed has a potential to provide valuable insights in understanding underlying mechanisms of pyruvate shuttling across the mitochondrial membrane. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

KRISHNA NAGAMPALLI, RAGHAVENDRA SASHI; NECIOSUP QUESNAY, JOSE EDWIN; ADAMOSKI, DOUGLAS; ISLAM, ZEYAUL; BIRCH, JAMES; SEBINELLI, HEITOR GOBBI; BRUNO MOREIRA GIRARD, RICHARD MARCEL; RODRIGUES ASCENCAO, CAROLLINE FERNANDA; FALA, ANGELA MARIA; PAULETTI, BIANCA ALVES; et al. Human mitochondrial pyruvate carrier 2 as an autonomous membrane transporter. SCIENTIFIC REPORTS, v. 8, FEB 22 2018. (17/02391-8, 14/20673-2, 16/06034-2, 15/02734-7, 15/25832-4, 14/17820-3, 14/12663-7, 14/06954-9)

QUESNAY, JOSE EDWIN NECIOSUP; POLLOCK, NAOMI L.; NAGAMPALLI, RAGHAVENDRA SASHI KRISHNA; LEE, SARAH C.; BALAKRISHNAN, VIJAYAKUMAR; DIAS, SANDRA MARTHA GOMES; MORAES, ISABEL; DAFFORN, TIM R.; AMBROSIO, ANDRE LUIS BERTELI. Insights on the Quest for the Structure-Function Relationship of the Mitochondrial Pyruvate Carrier. BIOLOGY-BASEL, v. 9, n. 11, NOV 2020. (14/20673-2, 17/11766-5, 19/02261-2, 13/07600-3, 14/06954-9, 18/00492-4, 17/02391-8, 15/02734-7)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

QUESÑAY, José Edwin Neciosup. Produção heteróloga, purificação, caracterização funcional e predição estrutural do carregador mitochondrial de piruvato humano. 2020. Doctoral Thesis - Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia Campinas, SP.