Abbreviation	Expanded Version
ER	Endoplasmic reticulum
UPR	Unfolded protein response
S1R	Sigma-1 Receptor
PERK	Double-stranded RNA-dependent protein kinase (PRK)-like ER kinase
ATF6	Activating transcription factor 6
IRE1	Inositol requiring enzyme 1
ERAD	Endoplasmic-reticulum-associated protein degradation
MAMs	Mitochondria-associated ER membranes
IP3R3	Inositol 1,4,5-trisphosphate receptor
XBP1	X-box binding protein 1
KD	Knock-down
siRNA	Small interfering RNA
GFP	Green fluorescent protein
DMSO	Dimethyl sulfoxide
ATP	Adenosine triphosphate
FRET	Förster resonance energy transfer
Ψm	Mitochondrial membrane potential
NADH	Nicotinamide adenine dinucleotide
IMS	Mitochondrial inter-membrane space
ROS	Reactive oxygen species
SERCA	Sarco(endo)plasmic reticulum Ca2+-ATPase
Sensor	Definition	Reference
mtAT1.03	Genetically encoded mitochondrial matrix targeted FRET-based ATP biosensor	[14]
TMRM	Tetramethylrhodamine methyl ester
D1ER	Genetically encoded ER targeted FRET-based Ca2+ biosensor	[17]
4mtD3cpv	Genetically encoded mitochondrial matrix targeted FRET-based Ca2+ biosensor	[18]
IMS-GEM-GECO	Genetically encoded mitochondrial IMS targeted ratiometric Ca2+ biosensor	[19,20]
mitoHyper7	Genetically encoded mitochondrial matrix targeted ratiometric ROS biosensor	[24]