2026-04-14T18:25:24Zhttps://uvadoc.uva.es/oai/request

oai:uvadoc.uva.es:10324/659232024-12-16T12:09:02Zcom_10324_1134com_10324_931com_10324_894col_10324_1213

De Marchi, Umberto Santo Domingo Mayoral, Jaime Castelbou, Cyril Sekler, Israel Wiederkehr, Andreas Demaurex, Nicolas 2024-02-07T14:59:11Z 2024-02-07T14:59:11Z 2014 J Biol Chem., Jul 2014, vol. 289, n. 29, p. 20377-85. 0021-9258 https://uvadoc.uva.es/handle/10324/65923 10.1074/jbc.M113.540898 20377 29 20385 Journal of Biological Chemistry 289 Mitochondria capture and subsequently release Ca(2+) ions, thereby sensing and shaping cellular Ca(2+) signals. The Ca(2+) uniporter MCU mediates Ca(2+) uptake, whereas NCLX (mitochondrial Na/Ca exchanger) and LETM1 (leucine zipper-EF-hand-containing transmembrane protein 1) were proposed to exchange Ca(2+) against Na(+) or H(+), respectively. Here we study the role of these ion exchangers in mitochondrial Ca(2+) extrusion and in Ca(2+)-metabolic coupling. Both NCLX and LETM1 proteins were expressed in HeLa cells mitochondria. The rate of mitochondrial Ca(2+) efflux, measured with a genetically encoded indicator during agonist stimulations, increased with the amplitude of mitochondrial Ca(2+) ([Ca(2+)]mt) elevations. NCLX overexpression enhanced the rates of Ca(2+) efflux, whereas increasing LETM1 levels had no impact on Ca(2+) extrusion. The fluorescence of the redox-sensitive probe roGFP increased during [Ca(2+)]mt elevations, indicating a net reduction of the matrix. This redox response was abolished by NCLX overexpression and restored by the Na(+)/Ca(2+) exchanger inhibitor CGP37157. The [Ca(2+)]mt elevations were associated with increases in the autofluorescence of NAD(P)H, whose amplitude was strongly reduced by NCLX overexpression, an effect reverted by Na(+)/Ca(2+) exchange inhibition. We conclude that NCLX, but not LETM1, mediates Ca(2+) extrusion from mitochondria. By controlling the duration of matrix Ca(2+) elevations, NCLX contributes to the regulation of NAD(P)H production and to the conversion of Ca(2+) signals into redox changes. spa info:eu-repo/semantics/openAccess NCLX Protein, but Not LETM1, Mediates Mitochondrial Ca2+ Extrusion, Thereby Limiting Ca2+-induced NAD(P)H Production and Modulating Matrix Redox State info:eu-repo/semantics/article