The gate of mitochondrial porin channel is controlled by a number of negative and positive charges

Mirzabekov, Tajib A.; Ermishkin, L. N.

doi:10.1016/0014-5793(89)80662-3

Cited by 17 publications

(17 citation statements)

References 9 publications

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“…At such low pH values, acidic charges are being neutralized, which increases the net effective positive charge involved in gating. Indeed, the involvement of many positive as well as negative charges in VDAC gating has been suggested previously (14). When pH was reduced symmetrically at both sides of the membrane, the pK a values calculated for n (Fig.…”

Section: Discussionsupporting

confidence: 64%

“…Correspondingly, neutralization of acidic charges leads to the increase of voltage-induced channel closure (11,14,32). A representative experiment illustrated by To quantify voltage-gating parameters upon acidification, we used a previously described approach (1,17,25,33).…”

Section: Acidification Increases Voltage Sensitivity Of Vdac-asmentioning

confidence: 99%

“…These data implied that VDAC gating should also respond to acidification, in which case the net channel charge should become more positive. The corresponding experiments demonstrated that acidification does indeed increase VDAC voltage sensitivity (11,14).…”

mentioning

confidence: 91%

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Acidification Asymmetrically Affects Voltage-dependent Anion Channel Implicating the Involvement of Salt Bridges

Teijido

Rappaport

Chamberlin

et al. 2014

Journal of Biological Chemistry

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Background: VDAC voltage gating depends on pH. Results: Acidification asymmetrically and reversibly enhances VDAC closure. Conclusion: pH-sensitive formation of stable salt bridges in the cytosolic side of VDAC explains its asymmetrical response to acidification. Significance: The pronounced sensitivity of the cytosolic side of VDAC to acidification provides new insights into the protective effect of cytosolic acidification during ischemia.

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Section: Discussionsupporting

confidence: 64%

Section: Acidification Increases Voltage Sensitivity Of Vdac-asmentioning

confidence: 99%

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Acidification Asymmetrically Affects Voltage-dependent Anion Channel Implicating the Involvement of Salt Bridges

Teijido

Rappaport

Chamberlin

et al. 2014

Journal of Biological Chemistry

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“…Further work is in progress at present to localize the FITC-modified lysines within the primary structure of the mitochondrial porin. groups [13] has presented evidence that as many as 22 positively charged groups could be involved in channel gating. This would mean that almost all basic amino acids present in the primary structure are involved in some 'delocalized' gating and that no cluster of gating charges exist within the channel-forming unit.…”

Section: Discussionmentioning

confidence: 99%

Positive residues involved in the voltage‐gating of the mitochondrial porin‐channel are localized in the external moiety of the pore

Pinto

jamal

Benz³

et al. 1990

FEBS Letters

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The role of positive charges located on the hydrophilic surface of the mitochondrial outer membrane channel was investigated by studying the interaction between LDAO-solubilized porin and a cation-exchanger column. The binding of porin to the column material was inhibited when the elution buffer had a pH of 9 or when 2 mM dextran sulfate was added to the buffer at neutral pH. Interestingly, the addition of a synthetic copolymer of methacrylate, maleate and styrene known as a potent modulator of the voltage-dependence, did not influence the interaction between column material and porin. Incubation of porin with fluorescein isothiocyanate (FITC) resulted in the isolation of a porin fraction in which on average two lysines located on the surface of the pore-forming complex per 35 kDa polypeptide were modified. The voltage-dependence of the fluorescein isothiocyanate modified porin was strongly decreased as compared with the unmodified porin. The experiments presented here give the first biochemical evidence that positively charged lysine residues located on the surface of the channel-forming complex are responsible for the gating of the mitochondrial porin-channel.Porin-pore; Voltage-dependence; Voltage sensor; Fluorescein isothiocyanate; Lauryl (dimethyl)-amine oxide; Mitochondria

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“…In addition, such active groups were found in the molecular structures of molecules of voltage-dependent, ryanodine-sensitive, and inositol trisphosphate calcium channels [16,17]. It was also demonstrated that changes in the level of ionization of these groups can effectively modulate the functioning of transport systems [18,19]. The existence of active SH and COOH groups was also shown in the composition of channel molecules of MPTPs.…”

Section: Introductionmentioning

confidence: 99%

Role of Carboxylic Groups in the Control of Nonspecific Permeability of Mitochondrial Membranes

2010

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Ionized COOH groups are present in molecular structures involved in the process of formation of mitochondrial permeability transition pores (MPTPs), in particular, in the ADP/ATP antiporter and/or voltage-dependent anion channels. In experiments on preparations of isolated mitochondria obtained from rat hepatocytes, we found that, in the case of induction of nonspecific permeability through mitochondrial membranes under the action of Cа 2+ in a relatively low concentration (15 µM), modulation of the activity of COOH groups with the use of 2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline (1 mM) led to unidirectional effects, namely to acceleration of the processes of formation of MPTPs and transport of incubation solution and Са 2+ through these megachannels, prolongation of the open state of the latter, as well as to increases in the final volume (swelling) of the mitochondria and to a rise in the amount of Са 2+ released from these organelles. In contrast, when calcium was used in a high concentration (100 µM), the directions of the above processes were dissimilar. Slowing down of the flow of incubation solution through MPTPs and the process of their formation was observed; at the same time, Са 2+ release from the mitochondria was accelerated. However, the final volume of the mitochondria and the amount of Са 2+ released from these cellular structures increased. Differences between the effects of the used modulator of the activity of COOH groups on the nonspecific permeability of the mitochondria induced by calcium applied in low and high concentrations are perhaps determined by the following. The process of swelling of the mitochondria is saturable, while Са 2+ release from these organelles shows an unlimited pattern. The latter process (Са 2+ release) probably undergoes calcium-initiated inactivation. The mechanisms of induction of nonspecific permeability of the mitochondrial membranes under the action of low and high calcium concentrations differ from each other. The calcium uniporter in the mitochondria is sensitive to the modulator of the activity of COOH groups. Diffusion of water through the inner mitochondrial membrane and/or other systems provides some contribution to the studied processes; this can lead to changes in the transport of liquids in these organelles.

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The gate of mitochondrial porin channel is controlled by a number of negative and positive charges

Cited by 17 publications

References 9 publications

Acidification Asymmetrically Affects Voltage-dependent Anion Channel Implicating the Involvement of Salt Bridges

Acidification Asymmetrically Affects Voltage-dependent Anion Channel Implicating the Involvement of Salt Bridges

Positive residues involved in the voltage‐gating of the mitochondrial porin‐channel are localized in the external moiety of the pore

Role of Carboxylic Groups in the Control of Nonspecific Permeability of Mitochondrial Membranes

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