The ER chaperone calnexin controls mitochondrial positioning and respiration.

The ER chaperone calnexin controls mitochondrial positioning and respiration. Sci Signal. 2020 Jun 30;13(638): Authors: Gutiérrez T, Qi H, Yap MC, Tahbaz N, Milburn LA, Lucchinetti E, Lou PH, Zaugg M, LaPointe PG, Mercier P, Overduin M, Bischof H, Burgstaller S, Malli R, Ballanyi K, Shuai J, Simmen T Abstract Chaperones in the endoplasmic reticulum (ER) control the flux of Ca2+ ions into mitochondria, thereby increasing or decreasing the energetic output of the oxidative phosphorylation pathway. An example is the abundant ER lectin calnexin, which interacts with sarco/endoplasmic reticulum Ca2+ ATPase (SERCA). We found that calnexin stimulated the ATPase activity of SERCA by maintaining its redox state. This function enabled calnexin to control how much ER Ca2+ was available for mitochondria, a key determinant for mitochondrial bioenergetics. Calnexin-deficient cells compensated for the loss of this function by partially shifting energy generation to the glycolytic pathway. These cells also showed closer apposition between the ER and mitochondria. Calnexin therefore controls the cellular energy balance between oxidative phosphorylation and glycolysis. PMID: 32606038 [PubMed - in process]
Source: Science Signaling - Category: Biomedical Science Authors: Tags: Sci Signal Source Type: research