Preprint ER-mitochondria distance is a critical parameter for efficient mitochondrial Ca2+ uptake and oxidative metabolism, 2024, Dematteis+

ER-mitochondria distance is a critical parameter for efficient mitochondrial Ca2+ uptake and oxidative metabolism.
Giulia Dematteis; Laura Tapella; Claudio Casali; Maria Talmon; Elisa Tonelli; Simone Reano; Adele Ariotti; Emanuela Pessolano; Mustyna Malecka; Gabriela Chrostek; Gabriele Kilkoviene; Danielius Umbrasas; Carla Distasi; Mariagrazia Grilli; Graham Ladds; Nicoletta Filigheddu; Lugia Grazia Fresu; Katsuhiko Mikoshiba; Carlos Matute; Paula Ramos-Gonzalez; Aiste Jekabsone; Tito Cali; Marisa Brini; Marco Biggiogera; Fabio Cavaliere; Riccardo Miggiano; Armando A Genazzani; Dmitry Lim

IP3 receptor (IP3R)-mediated Ca2+ transfer at the mitochondria-endoplasmic reticulum (ER) contact sites (MERCS) drives mitochondrial Ca2+ uptake and oxidative metabolism and is linked to different pathologies, including Parkinson's disease (PD). The dependence of Ca2+ 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 Ca2+ indicators targeting the ER lumen and the sub-mitochondrial compartments, we now show that a distance of ~20 nm is optimal for Ca2+ transfer and mitochondrial oxidative metabolism due to enrichment of IP3R at MERCS. In human iPSC-derived astrocytes from PD patients, 20 nm MERCS were specifically reduced which correlated with a reduction of mitochondrial Ca2+ uptake.

Our work determines with precision the optimal distance for Ca2+ flux between ER and mitochondria and suggests a new paradigm for fine control over mitochondrial function.


Link | PDF (Preprint: BioRxiv) [Open Access]