Structural studies of the Na+/Ca2+ exchanger by high-resolution nuclear magnetic resonance spectroscopy

• Grant number: 19/19968-1
• Support Opportunities: Regular Research Grants
• Start date: May 01, 2020
• End date: April 30, 2023
• Field of knowledge: Biological Sciences - Biophysics - Molecular Biophysics
• Principal Investigator: Roberto Kopke Salinas
• Grantee: Roberto Kopke Salinas
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 21/10013-9 - Biophysical characterization of the CALX-1.2 CBD12 domain, BP.TT; 21/00636-9 - Backbone resonance assignment of CALX-CBD12 in the Apo and Holo states, BP.TT

Abstract

Na+/Ca2+ exchangers (NCX) are membrane proteins that use the electrochemical gradient of Na+ to remove Ca2+ from the cytosol. They are essential for the maintenance of the intracellular Ca2+ homeostasis in various cell types, especially in excitable cells. CALX, the Na+/Ca2+ exchanger from Drosophila melanogaster, is found in sensory neuronal cells. It displays a unique regulatory behavior because it is inhibited instead of activated by intracellular Ca2+ as all other eukaryotic exchangers. The aim of this proposal is to investigate the structure of the CALX, and the mechanism of allosteric regulation of this exchanger. We will use NMR spectroscopy as the main technique. Specifically, the aims of the present proposal are: i) to characterize the oligomerization state and the functionality of the Na+/Ca2+ exchanger from the hyperthermophilic archaea Methanococcus janaschii, isolated in the presence of detergent micelles; ii) to investigate in atomic detail the mechanism of the CALX allosteric regulation by intracellular Ca2+. With respect to the latter, we will use solution NMR spectroscopy and isothermal titration calorimetry (ITC) to study soluble fragments of the exchanger in the absence and presence of Ca2+. We will also carry out Ca2+ transport assays with the full-length exchanger and mutants in cell. (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)

DE SOUZA DEGENHARDT, MAXIMILIA F.; VITALE, PHELIPE A. M.; ABIKO, LAYARA A.; ZACHARIAS, MARTIN; SATTLER, MICHAEL; OLIVEIRA, CRISTIANO L. P.; SALINAS, ROBERTO K.. Molecular insights on CALX-CBD12 interdomain dynamics from MD simulations, RDCs, and SAXS. BIOPHYSICAL JOURNAL, v. 120, n. 17, p. 3664-3675, SEP 7 2021. (18/16092-5, 16/24531-3, 19/19968-1, 17/05614-8, 16/07490-1)

AQUINO, GIOVANA PARREIRA DE; GOMES, MARCO ANTONIO MENDES; SALINAS, ROBERTO KOPKE; LARANJEIRA-SILVA, MARIA FERNANDA. Lipid and fatty acid metabolism in trypanosomatids. MICROBIAL CELL, v. 8, n. 11, p. 262-275, NOV 2021. (18/15971-5, 19/19968-1)