Journal Article

ER-mitochondria distance is a critical parameter for efficient mitochondrial Ca 2+ uptake and oxidative metabolism

Ladds, Graham, Fresu, Luigia Grazia, Filigheddu, Nicoletta, Grilli, Mariagrazia, Talmon, Maria, Mikoshiba, Katsuhiko, Cavaliere, Fabio, Malecka, Justyna, Pessolano, Emanuela, Ramos-Gonzalez, Paula, Brini, Marisa, Chrostek, Gabriela, Jekabsone, Aiste, Tonelli, Elisa, Lim, Dmitry, Calì, Tito, Dematteis, Giulia, Tapella, Laura, Distasi, Carla, Genazzani, Armando A, Casali, Claudio, Ariotti, Adele, Miggiano, Riccardo, Umbrasas, Danielius, Matute, Carlos, Biggiogera, Marco, Kulkovienė, Gabrielė, Reano, Simone

2024

Overview

IP receptor (IP R)-mediated Ca transfer at the mitochondria-endoplasmic reticulum (ER) contact sites (MERCS) drives mitochondrial Ca uptake and oxidative metabolism and is linked to different pathologies, including Parkinson's disease (PD). The dependence of Ca transfer efficiency on the ER-mitochondria distance remains unexplored. Employing molecular rulers that stabilize ER-mitochondrial distances at 5 nm resolution, and using genetically encoded Ca indicators targeting the ER lumen and the sub-mitochondrial compartments, we now show that a distance of ~20 nm is optimal for Ca transfer and mitochondrial oxidative metabolism due to enrichment of IP R at MERCS. In human iPSC-derived astrocytes from PD patients, 20 nm MERCS were specifically reduced, which correlated with a reduction of mitochondrial Ca uptake. Stabilization of the ER-mitochondrial interaction at 20 nm, but not at 10 nm, fully rescued mitochondrial Ca uptake in PD astrocytes. Our work determines with precision the optimal distance for Ca flux between ER and mitochondria and suggests a new paradigm for fine control over mitochondrial function.

• Subject: Astrocytes - metabolism / Calcium - metabolism / Calcium Signaling / Endoplasmic Reticulum - metabolism / Humans / Induced Pluripotent Stem Cells - cytology / Induced Pluripotent Stem Cells - metabolism / Inositol 1,4,5-Trisphosphate Receptors - metabolism / Mitochondria - metabolism / Oxidation-Reduction / Parkinson Disease - metabolism / Parkinson Disease - pathology