The mitochondrial membrane potential (ΔΨm) is essential for energy storage during oxidative phosphorylation, as it, along with the proton gradient (ΔpH), forms the transmembrane potential of hydrogen ions used to generate ATP. ΔΨm and ATP levels are maintained relatively stable, but sustained changes can be harmful. ΔΨm plays a key role in mitochondrial homeostasis by selectively eliminating dysfunctional mitochondria and driving the transport of ions and proteins necessary for mitochondrial function. The paper discusses additional mechanisms where ΔΨm is essential for cellular health and viability, and provides recommendations for accurately measuring ΔΨm in cells, while discussing potential sources of artifacts. ΔΨm is involved in various cellular processes, including the transport of cations and anions, the regulation of mitochondrial function, and the maintenance of mitochondrial quality control through mitophagy. It also influences the transport of nucleic acids and the biogenesis of iron-sulfur clusters, which are crucial for many cellular processes. The paper also discusses the role of ΔΨm in the transport of tRNAs and the regulation of mitochondrial DNA. The paper highlights the importance of ΔΨm in maintaining cellular homeostasis, and the consequences of its instability, such as mitochondrial dysfunction and cell death. It also discusses the mechanisms by which ΔΨm is maintained, including the function of the adenine nucleotide transporter (ANT) and the ATPase inhibitory factor 1 (IF1). The paper also discusses the potential for ΔΨm to be used as a therapeutic target, particularly in conditions associated with aging, obesity, and oxidative stress. The paper also discusses the challenges in measuring ΔΨm accurately, including the influence of various factors such as membrane potential, ion leakage, and the use of fluorescent probes. It highlights the importance of considering these factors when interpreting ΔΨm measurements and the potential for artifacts to affect the results. The paper concludes that ΔΨm is a critical component of mitochondrial function and cellular homeostasis, and that its maintenance is essential for the proper functioning of cells.The mitochondrial membrane potential (ΔΨm) is essential for energy storage during oxidative phosphorylation, as it, along with the proton gradient (ΔpH), forms the transmembrane potential of hydrogen ions used to generate ATP. ΔΨm and ATP levels are maintained relatively stable, but sustained changes can be harmful. ΔΨm plays a key role in mitochondrial homeostasis by selectively eliminating dysfunctional mitochondria and driving the transport of ions and proteins necessary for mitochondrial function. The paper discusses additional mechanisms where ΔΨm is essential for cellular health and viability, and provides recommendations for accurately measuring ΔΨm in cells, while discussing potential sources of artifacts. ΔΨm is involved in various cellular processes, including the transport of cations and anions, the regulation of mitochondrial function, and the maintenance of mitochondrial quality control through mitophagy. It also influences the transport of nucleic acids and the biogenesis of iron-sulfur clusters, which are crucial for many cellular processes. The paper also discusses the role of ΔΨm in the transport of tRNAs and the regulation of mitochondrial DNA. The paper highlights the importance of ΔΨm in maintaining cellular homeostasis, and the consequences of its instability, such as mitochondrial dysfunction and cell death. It also discusses the mechanisms by which ΔΨm is maintained, including the function of the adenine nucleotide transporter (ANT) and the ATPase inhibitory factor 1 (IF1). The paper also discusses the potential for ΔΨm to be used as a therapeutic target, particularly in conditions associated with aging, obesity, and oxidative stress. The paper also discusses the challenges in measuring ΔΨm accurately, including the influence of various factors such as membrane potential, ion leakage, and the use of fluorescent probes. It highlights the importance of considering these factors when interpreting ΔΨm measurements and the potential for artifacts to affect the results. The paper concludes that ΔΨm is a critical component of mitochondrial function and cellular homeostasis, and that its maintenance is essential for the proper functioning of cells.