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Updated: Jun 7, 2026
Imaging Mitochondrial Ca2+ Uptake in Astrocytes and Neurons using Genetically Encoded Ca2+ Indicators (GECIs)
Published on: January 22, 2022
Overexpressing GRP78 influences Ca2+ handling and function of mitochondria in astrocytes after ischemia-like stress
Yi-Bing Ouyang1, Li-Jun Xu, John F Emery
1Department of Anesthesia, Stanford University School of Medicine, Stanford, CA 94305, USA.
Abstract:
Ca(2+) transfer from endoplasmic reticulum (ER) to mitochondria at contact sites between the organelles can induce mitochondrial dysfunction and programmed cell death after stress. The ER-localized chaperone glucose-regulated protein 78kDa (GRP78/BiP) protects neurons against excitotoxicity and apoptosis. Here we show that overexpressing GRP78 protects astrocytes against ischemic injury, reduces net flux of Ca(2+) from ER to mitochondria, increases Ca(2+) uptake capacity in isolated mitochondria, reduces free radical production, and preserves respiratory activity and mitochondrial membrane potential after stress. We conclude that GRP78 influences ER-mitochondrial Ca(2+) crosstalk to maintain mitochondrial function and protect astrocytes from ischemic injury.
