Monitoring of the mitochondrial and plasma membrane potentials in human fibroblasts by tetraphenylphosphonium ion distribution.
The lipophilic cation tetraphenylphosphonium (TPP+) is accumulated by human skin fibroblasts across both the plasma and mitochondrial membranes. We show here that TPP+ uptake is indeed greatly decreased under conditions leading to de-energization of mitochondria. The TPP+ accumulation in the presence of the proton ionophore FCCP has been used for determination of the plasma membrane potential across the plasma membrane, after correction for potential-independent binding of TPP+ to cellular components. Following this procedure, a value of 75 mV has been obtained. Through the amount of TPP+ released by FCCP treatment, an estimate of the in situ mitochondrial membrane potential has been made. Furthermore, we report that the mitochondrial component of TPP+ accumulation decreases with aging of fibroblast cultures.
Dipartimento di Biologia Evoluzionistica e Sperimentale, Universitá di Bologna, Italy.
M
M
Rugolo
G
G
Lenaz
D002462:Cell Membrane / Q000502:physiology*; D005347:Fibroblasts / Q000378:metabolism / Q000502:physiology; D006801:Humans; D007425:Intracellular Membranes / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials; D008928:Mitochondria / Q000502:physiology*; D009861:Onium Compounds / Q000378:metabolism*; D009943:Organophosphorus Compounds / Q000378:metabolism*; D012867:Skin / Q000378:metabolism
D009861:Onium Compounds; D009943:Organophosphorus Compounds; C013289:tetraphenylphosphonium