Evidence for a novel voltage‐activated channel in the outer mitochondrial membrane

Kinnally, Kathleen W.; Tedeschi, Henry; Mannella, C.A.

doi:10.1016/0014-5793(87)80555-0

Cited by 30 publications

(20 citation statements)

References 22 publications

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“…The only previous studies on integral liver mitochondria with the patch clamp technique (Kinnally et al 1987(Kinnally et al , 1989bTedeschi et al 1987Tedeschi et al , 1989) yielded a rather different picture than that reported here, for the ionic permeability of the OM. Basically, no single channels but only high intensity currents were recorded.…”

Section: Discussioncontrasting

confidence: 64%

“…Recently, the patch clamp technique has been applied to integral mitochondria (Kinnally et al 1987(Kinnally et al , 1989bTedeschi et al 1987Tedeschi et al , 1989, and high intensity currents have been recorded. The lack, under these conditions, of single channel events, was judged an expected phenomenon, as in Neurospora crassa (Freitag et al 1982) and liver (De Pinto et al 1987) mitochondria, the expression of the VDAC is such that a few thousand molecules are likely to be present in a membrane area equal to that of a pipette patch.…”

Section: Introductionmentioning

confidence: 99%

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Ionic permeability of the mitochondrial outer membrane

et al. 1992

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The ionic permeability of the outer mitochondrial membrane (OMM) was studied with the patch clamp technique. Electrical recording of intact mitochondria (hence of the outer membrane (OM], derived from mouse liver, showed the presence of currents corresponding to low conductances (less than 50 pS), as well as of four distinct conductances of 99 pS, 152 pS, 220 pS and 307 pS (in 150 mM KCl). The latter were voltage gated, being open preferentially at positive (pipette) potentials. Very similar currents were found by patch clamping liposomes containing the isolated OM derived from rat brain mitochondria. Here a conductance of approximately 530 pS, resembling in its electrical characteristics a conductance already attributed to mitochondrial contact sites (Moran et al. 1990), was also detected. Immunoblot assays of mitochondria and of the isolated OM with antibodies against the outer membrane voltage-dependent anion channel (VDAC) (Colombini 1979), showed the presence of the anion channel in each case. However, the typical electrical behaviour displayed by such a channel in planar bilayers could not be detected under our experimental conditions. From this study, the permeability of the OMM appears different from what has been reported hitherto, yet is more in line with that multifarious and dynamic structure which apparently should belong to it, at least within the framework of mitochondrial biogenesis (Pfanner and Neupert 1990).

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Section: Discussioncontrasting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Ionic permeability of the mitochondrial outer membrane

et al. 1992

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“…The possibility that the IMM channel might serve, autonomously or in conjunction with channels present in the outer membrane (Colombini, 1979;Kinnally et al, 1987), in the machinery for the import of cytoplasmically synthesized mitochondrial proteins has already been considered by us (Sorgato et al, 1987) and by others (Thieffry et aI., 1988). The import apparatus seems to lie in those regions where the two mitochondrial membranes are juxtaposed (Hartl et al, 1989).…”

Section: Discussionmentioning

confidence: 98%

Further investigation on the high-conductance ion channel of the inner membrane of mitochondria

Sorgato

Morán

Pinto

et al. 1989

J Bioenerg Biomembr

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By use of the patch-clamp technique, the inner membrane of mouse liver and heart mitochondria is shown to contain a highly conductive (around t00 pS in symmetrical 150 mM KC1) and voltage-dependent ion channel. This channel closely resembles that previously found in cuprizone-treated mouse liver inner mitochondrial membrane. The paper discusses the electrical properties of the channel and its possible physiological function. The reconstitution in giant liposomes of a partially purified ox heart inner membrane fraction containing the channel and the use of various inhibitors are also presented.

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“…In fact, the existence of a second ionic channel in the outer membrane was suggested by the properties of the porin-deficient mutants [31], the growth of which was unaffected under aerobic conditions. It was also suggested in 'patch-clamp' experiments on giant mitochondria [3], where a second conductance was induced by voltage jumps. A cationic channel has been observed by reconstitution in bilayers of detergent-solubilized outer membranes of porin-deficient yeast mutants [4].…”

Section: Discussionmentioning

confidence: 99%

A peptide‐sensitive channel of large conductance is localized on mitochondrial outer membrane

Chich

Goldschmidt²,

Thieffry

et al. 1991

European Journal of Biochemistry

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Applying the technique of 'tip-dip' to mitochondria, we have shown the existence in this organelle of a cationic channel of large conductance, which is blocked by a 13-residue peptide possessing the sequence of the N-terminal extremity of the cytochrome c oxidase subunit IV precursor. To study the submitochondrial localization of the channel, the effect of trypsin on isolated channels and on entire mitochondria were compared. One side of isolated channels is sensitive to trypsin, which eliminates the voltage dependence. Channels isolated from trypsinized mitochondria were devoid of voltage dependence and were blocked by the peptide. This suggests a localization of the channel on the outer membrane. Consistent with this hypothesis, the channel was observed with the highest frequency in outer membrane fractions purified by different procedures, either from bovine adrenal cortex or from rat liver mitochondria. Such a localization is also consistent with digitonin solubilization experiments. The channel was solubilized before the inner membrane marker, cytochrome c oxidase. The orientation of the channel was inferred from its trypsin sensitivity and its potential dependence: a transmembrane potential (inside negative) will close the channel.Mitochondria are classically viewed as possessing a very permeable outer membrane, the permeability of which is attributed to a voltage-dependent anion channel (VDAC) [l], and an impermeable inner membrane equipped only with transporters. This view was based on the different functions of the two membranes and on the differences between channels and transporters, since mitochondrial ionic gradients seem to exclude the presence through the inner membrane of the large ionic flux generally associated with ionic channels. However, methodological progress has been made in the investigation of the electrical properties of organelle membranes and new mitochondrial channels have been described [2 -71. These new channels are ascribed to outer and inner membranes and also to contact sites between these membranes.We have described a cationic channel of large conductance and with rapid kinetics [2]. The most striking property of this channel is that it is blocked by a 13-residue peptide possessing the sequence of the N-terminal extremity of cytochrome c oxidase subunit IV precursor: MLSLRQSIRFFKY (peptide M) [8]. This peptide-sensitive channel (PSC) was characterized by the technique of 'tip-dip', which allows the study of membranes irrespective of their size [9 -111. However, because total mitochondria membrane fragments were used, it was necessary to determine the sub-mitochondrial origin of PSC. In the present communication, this question was investigated by comparing the distribution of the channel, as determined from the frequency of observation of the characteristic electrical activity in membrane fragments, to the distribution of various mitochondrial markers. EXPERIMENTAL PROCEDURES M a terialsTrypsin (treated with N-tosyl-L-phenylalanylchloromethane) and digitonin were purchased from...

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Evidence for a novel voltage‐activated channel in the outer mitochondrial membrane

Cited by 30 publications

References 22 publications

Ionic permeability of the mitochondrial outer membrane

Ionic permeability of the mitochondrial outer membrane

Further investigation on the high-conductance ion channel of the inner membrane of mitochondria

A peptide‐sensitive channel of large conductance is localized on mitochondrial outer membrane

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