Mitochondrial inner membrane and membrane potential (IMM/MMP)

The mitochondrial inner membrane (IMM) is a highly specialized lipid bilayer that serves as the functional heart of cellular energy metabolism, housing the electron transport chain (ETC) and ATP synthase (Alberts et al., Molecular Biology of the Cell, 2002). The mitochondrial membrane potential (MMP) is the electrical component of the electrochemical proton gradient established by the ETC, typically maintained at a high negative value (-150 to -180 mV) relative to the cytosol (Zorova et al., Analytical Biochemistry, 2018). This potential is indispensable for driving the synthesis of ATP, facilitating the import of essential proteins, and regulating mitochondrial ion homeostasis and signaling (Perry et al., Methods in Cell Biology, 2011). In pathological states, the IMM and its potential are often compromised; cancer cells frequently exhibit hyperpolarization to support metabolic reprogramming and resist cell death, whereas depolarization is a common feature of mitochondrial dysfunction in neurodegenerative and cardiovascular diseases (Chen, Annual Review of Cell Biology, 1988). Therapeutic interventions targeting this system include uncoupling agents that dissipate the gradient to increase metabolic flux and mitotropic compounds designed to selectively deliver antioxidants or other payloads to the mitochondrial matrix (Smith et al., Annals of the New York Academy of Sciences, 2015).

Other names

Inner mitochondrial membraneMitochondrial membrane potentialDelta-psi-mMMPIMMMitochondrial electrochemical gradient

Pharmacological agents interact with the mitochondrial inner membrane and its potential through several mechanisms: protonophores (uncouplers) transport protons across the membrane to dissipate the electrochemical gradient; lipophilic cations utilize the negative potential to accumulate within the matrix; and electron transport chain inhibitors prevent the generation of the potential by blocking redox reactions.