Ion permeability induced in artificial membranes by the ATP/ADP antiporter

Abstract

The hypothesis on the additional function of the ATP/ADP antiporter (ANT) as uncoupling protein has been tested in proteoliposomes and planar bilayer phospholipid membranes (BLM). It is found that dissipation of the light-induced dpH in the dark is very much faster in ANT-bacteriorhodopsin proteoliposomes than in proteoliposomes containing bacteriorhodopsin as the only protein. Mersalyl treatment of ANT-bacteriorhodopsin proteoliposomes causes further increase in the dpH dissipation rate due to formation of a high conductance pore. The properties of this pore are studied on ANT incorporated to BLM. They proved to be similar to those of so-called multiple conductance channel or permeability transition pore of inner mitochondrial membrane. The conductance of the single channel is as high as 2.2 nS. The channel fails to discriminate between K', Na', H' and Cl-. Thus the obtained data are consistent with the assumption that native and modified ANT might function as an H'-specific conductor and as a permeability transition pore, respectively.

The Reversible Antiport-Uniport Conversion of the Phosphate Carrier from Yeast Mitochondria Depends on the Presence of a Single Cysteine

“…Furthermore, a number of studies using electrophysiological techniques provide evidence for channel properties in carrier proteins, e.g. neurotransmitter transporters (Cammack and Schwartz, 1996;DeFelice and Blakely, 1996), the chloroplast triose phosphate carrier (Schwarz et al, 1994) as well as the mitochondrial ADP/ATP carrier (Tikhonova et al, 1994;Brustovetsky and Klingenberg, 1996). This concept is particularly attractive in view of the fact that conditions are known where large pores appear in the inner mitochondrial membrane (permeability transition pore, "megachannel") (Zoratti and Szabo, 1995;Bernardi and Petronilli, 1996).…”

Mitochondrial carrier proteins can reversibly change their transport mode: the cases of the aspartate/glutamate and the phosphate carrier

“…Furthermore, a number of studies using electrophysiological techniques provide evidence for channel properties in carrier proteins, e.g. neurotransmitter transporters (Cammack & Schwartz, 1996;DeFelice & Blakely, 1996), the chloroplast triose phosphate carrier (Schwarz, Gross, Steinkamp & Flugge, 1994) as well as the mitochondrial ADP/ATP carrier (Tikhonova, Andreyev, Antonenko, Kaulen, Komrakov & Skulachev, 1994;Brustovetsky & Klingenberg, 1996).…”

The role of creatine kinase in inhibition of mitochondrial permeability transition

“…ADP and bonkregic acid, or the immuno-suppressant drug cyclosporin A (CspA) [9 l l]. Recent publications have indicated that the PTP consists of either ANT alone [12,13], or a multi-protein complex consisting, in part, of hexokinase, porin and ANT [141.…”