Comparison of the ion channel characteristics of proapoptotic BAX and antiapoptotic BCL-2

Paul H. Schlesinger, Atan Gross, Xiao-Ming Yin, Kazuhito Yamamoto, Mitsuyoshi Saito, Gabriel Waksman, Stanley J. Korsmeyer

Research output: Contribution to journalArticle

431 Citations (Scopus)

Abstract

The BCL-2 family of proteins is composed of both pro- and antiapoptotic regulators, although its most critical biochemical functions remain uncertain. The structural similarity between the BCL-X(L) monomer and several ion-pore-forming bacterial toxins has prompted electrophysiologic studies. Both BAX and BCL-2 insert into KCl-loaded vesicles in a pH-dependent fashion and demonstrate macroscopic ion efflux. Release is maximum at ≃pH 4.0 for both proteins; however, BAX demonstrates a broader pH range of activity. Both purified proteins also insert into planar lipid bilayers at pH 4.0. Single- channel recordings revealed a minimal channel conductance for BAX of 22 pS that evolved to channel currents with at least three subconductance levels. The final, apparently stable BAX channel had a conductance of 0.731 nS at pH 4.0 that changed to 0.329 nS when shifted to pH 7.0 but remained mildly Cl- selective and predominantly open. When BAX-incorporated lipid vesicles were fused to planar lipid bilayers at pH 7.0, a Cl- -selective (P(K)/P(Cl) = 0.3) 1.5-nS channel displaying mild inward rectification was noted. In contrast, BCL-2 formed mildly K+-selective (P(K)/P(Cl) = 3.9) channels with a most prominent initial conductance of 80 pS that increased to 1.90 nS. Fusion of BCL-2-incorporated lipid vesicles into planar bilayers at pH 7.0 also revealed mild K+ selectivity (P(K)/P(Cl) = 2.4) with a maximum conductance of 1.08 nS. BAX and BCL-2 each form channels in artificial membranes that have distinct characteristics including ion selectivity, conductance, voltage dependence, and rectification. Thus, one role of these molecules may include pore activity at selected membrane sites.

Original languageEnglish (US)
Pages (from-to)11357-11362
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume94
Issue number21
DOIs
StatePublished - Oct 14 1997
Externally publishedYes

Fingerprint

Ion Channels
Lipid Bilayers
Ions
Artificial Membranes
Bacterial Toxins
Lipids
Proteins
Membranes

ASJC Scopus subject areas

  • Genetics
  • General

Cite this

Comparison of the ion channel characteristics of proapoptotic BAX and antiapoptotic BCL-2. / Schlesinger, Paul H.; Gross, Atan; Yin, Xiao-Ming; Yamamoto, Kazuhito; Saito, Mitsuyoshi; Waksman, Gabriel; Korsmeyer, Stanley J.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 94, No. 21, 14.10.1997, p. 11357-11362.

Research output: Contribution to journalArticle

Schlesinger, Paul H. ; Gross, Atan ; Yin, Xiao-Ming ; Yamamoto, Kazuhito ; Saito, Mitsuyoshi ; Waksman, Gabriel ; Korsmeyer, Stanley J. / Comparison of the ion channel characteristics of proapoptotic BAX and antiapoptotic BCL-2. In: Proceedings of the National Academy of Sciences of the United States of America. 1997 ; Vol. 94, No. 21. pp. 11357-11362.
@article{5babadf78af64113b2df2a9ab6c52268,
title = "Comparison of the ion channel characteristics of proapoptotic BAX and antiapoptotic BCL-2",
abstract = "The BCL-2 family of proteins is composed of both pro- and antiapoptotic regulators, although its most critical biochemical functions remain uncertain. The structural similarity between the BCL-X(L) monomer and several ion-pore-forming bacterial toxins has prompted electrophysiologic studies. Both BAX and BCL-2 insert into KCl-loaded vesicles in a pH-dependent fashion and demonstrate macroscopic ion efflux. Release is maximum at ≃pH 4.0 for both proteins; however, BAX demonstrates a broader pH range of activity. Both purified proteins also insert into planar lipid bilayers at pH 4.0. Single- channel recordings revealed a minimal channel conductance for BAX of 22 pS that evolved to channel currents with at least three subconductance levels. The final, apparently stable BAX channel had a conductance of 0.731 nS at pH 4.0 that changed to 0.329 nS when shifted to pH 7.0 but remained mildly Cl- selective and predominantly open. When BAX-incorporated lipid vesicles were fused to planar lipid bilayers at pH 7.0, a Cl- -selective (P(K)/P(Cl) = 0.3) 1.5-nS channel displaying mild inward rectification was noted. In contrast, BCL-2 formed mildly K+-selective (P(K)/P(Cl) = 3.9) channels with a most prominent initial conductance of 80 pS that increased to 1.90 nS. Fusion of BCL-2-incorporated lipid vesicles into planar bilayers at pH 7.0 also revealed mild K+ selectivity (P(K)/P(Cl) = 2.4) with a maximum conductance of 1.08 nS. BAX and BCL-2 each form channels in artificial membranes that have distinct characteristics including ion selectivity, conductance, voltage dependence, and rectification. Thus, one role of these molecules may include pore activity at selected membrane sites.",
author = "Schlesinger, {Paul H.} and Atan Gross and Xiao-Ming Yin and Kazuhito Yamamoto and Mitsuyoshi Saito and Gabriel Waksman and Korsmeyer, {Stanley J.}",
year = "1997",
month = "10",
day = "14",
doi = "10.1073/pnas.94.21.11357",
language = "English (US)",
volume = "94",
pages = "11357--11362",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
number = "21",

}

TY - JOUR

T1 - Comparison of the ion channel characteristics of proapoptotic BAX and antiapoptotic BCL-2

AU - Schlesinger, Paul H.

AU - Gross, Atan

AU - Yin, Xiao-Ming

AU - Yamamoto, Kazuhito

AU - Saito, Mitsuyoshi

AU - Waksman, Gabriel

AU - Korsmeyer, Stanley J.

PY - 1997/10/14

Y1 - 1997/10/14

N2 - The BCL-2 family of proteins is composed of both pro- and antiapoptotic regulators, although its most critical biochemical functions remain uncertain. The structural similarity between the BCL-X(L) monomer and several ion-pore-forming bacterial toxins has prompted electrophysiologic studies. Both BAX and BCL-2 insert into KCl-loaded vesicles in a pH-dependent fashion and demonstrate macroscopic ion efflux. Release is maximum at ≃pH 4.0 for both proteins; however, BAX demonstrates a broader pH range of activity. Both purified proteins also insert into planar lipid bilayers at pH 4.0. Single- channel recordings revealed a minimal channel conductance for BAX of 22 pS that evolved to channel currents with at least three subconductance levels. The final, apparently stable BAX channel had a conductance of 0.731 nS at pH 4.0 that changed to 0.329 nS when shifted to pH 7.0 but remained mildly Cl- selective and predominantly open. When BAX-incorporated lipid vesicles were fused to planar lipid bilayers at pH 7.0, a Cl- -selective (P(K)/P(Cl) = 0.3) 1.5-nS channel displaying mild inward rectification was noted. In contrast, BCL-2 formed mildly K+-selective (P(K)/P(Cl) = 3.9) channels with a most prominent initial conductance of 80 pS that increased to 1.90 nS. Fusion of BCL-2-incorporated lipid vesicles into planar bilayers at pH 7.0 also revealed mild K+ selectivity (P(K)/P(Cl) = 2.4) with a maximum conductance of 1.08 nS. BAX and BCL-2 each form channels in artificial membranes that have distinct characteristics including ion selectivity, conductance, voltage dependence, and rectification. Thus, one role of these molecules may include pore activity at selected membrane sites.

AB - The BCL-2 family of proteins is composed of both pro- and antiapoptotic regulators, although its most critical biochemical functions remain uncertain. The structural similarity between the BCL-X(L) monomer and several ion-pore-forming bacterial toxins has prompted electrophysiologic studies. Both BAX and BCL-2 insert into KCl-loaded vesicles in a pH-dependent fashion and demonstrate macroscopic ion efflux. Release is maximum at ≃pH 4.0 for both proteins; however, BAX demonstrates a broader pH range of activity. Both purified proteins also insert into planar lipid bilayers at pH 4.0. Single- channel recordings revealed a minimal channel conductance for BAX of 22 pS that evolved to channel currents with at least three subconductance levels. The final, apparently stable BAX channel had a conductance of 0.731 nS at pH 4.0 that changed to 0.329 nS when shifted to pH 7.0 but remained mildly Cl- selective and predominantly open. When BAX-incorporated lipid vesicles were fused to planar lipid bilayers at pH 7.0, a Cl- -selective (P(K)/P(Cl) = 0.3) 1.5-nS channel displaying mild inward rectification was noted. In contrast, BCL-2 formed mildly K+-selective (P(K)/P(Cl) = 3.9) channels with a most prominent initial conductance of 80 pS that increased to 1.90 nS. Fusion of BCL-2-incorporated lipid vesicles into planar bilayers at pH 7.0 also revealed mild K+ selectivity (P(K)/P(Cl) = 2.4) with a maximum conductance of 1.08 nS. BAX and BCL-2 each form channels in artificial membranes that have distinct characteristics including ion selectivity, conductance, voltage dependence, and rectification. Thus, one role of these molecules may include pore activity at selected membrane sites.

UR - http://www.scopus.com/inward/record.url?scp=0030779846&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030779846&partnerID=8YFLogxK

U2 - 10.1073/pnas.94.21.11357

DO - 10.1073/pnas.94.21.11357

M3 - Article

C2 - 9326614

AN - SCOPUS:0030779846

VL - 94

SP - 11357

EP - 11362

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 21

ER -