Cargando…
Visual and functional demonstration of growing Bax-induced pores in mitochondrial outer membranes
Bax induces mitochondrial outer membrane permeabilization (MOMP), a critical step in apoptosis in which proteins are released into the cytoplasm. To resolve aspects of the mechanism, we used cryo-electron microscopy (cryo-EM) to visualize Bax-induced pores in purified mitochondrial outer membranes (...
Autores principales: | , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The American Society for Cell Biology
2015
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4294680/ https://www.ncbi.nlm.nih.gov/pubmed/25411335 http://dx.doi.org/10.1091/mbc.E13-11-0638 |
_version_ | 1782352750362755072 |
---|---|
author | Gillies, Laura A Du, Han Peters, Bjoern Knudson, C. Michael Newmeyer, Donald D. Kuwana, Tomomi |
author_facet | Gillies, Laura A Du, Han Peters, Bjoern Knudson, C. Michael Newmeyer, Donald D. Kuwana, Tomomi |
author_sort | Gillies, Laura A |
collection | PubMed |
description | Bax induces mitochondrial outer membrane permeabilization (MOMP), a critical step in apoptosis in which proteins are released into the cytoplasm. To resolve aspects of the mechanism, we used cryo-electron microscopy (cryo-EM) to visualize Bax-induced pores in purified mitochondrial outer membranes (MOMs). We observed solitary pores that exhibited negative curvature at their edges. Over time, the pores grew to ∼100–160 nm in diameter after 60–90 min, with some pores measuring more than 300 nm. We confirmed these results using flow cytometry, which we used to monitor the release of fluorescent dextrans from isolated MOM vesicles. The dextran molecules were released gradually, in a manner constrained by pore size. However, the release rates were consistent over a range of dextran sizes (10–500 kDa). We concluded that the pores were not static but widened dramatically to release molecules of different sizes. Taken together, the data from cryo-EM and flow cytometry argue that Bax promotes MOMP by inducing the formation of large, growing pores through a mechanism involving membrane-curvature stress. |
format | Online Article Text |
id | pubmed-4294680 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | The American Society for Cell Biology |
record_format | MEDLINE/PubMed |
spelling | pubmed-42946802015-03-30 Visual and functional demonstration of growing Bax-induced pores in mitochondrial outer membranes Gillies, Laura A Du, Han Peters, Bjoern Knudson, C. Michael Newmeyer, Donald D. Kuwana, Tomomi Mol Biol Cell Articles Bax induces mitochondrial outer membrane permeabilization (MOMP), a critical step in apoptosis in which proteins are released into the cytoplasm. To resolve aspects of the mechanism, we used cryo-electron microscopy (cryo-EM) to visualize Bax-induced pores in purified mitochondrial outer membranes (MOMs). We observed solitary pores that exhibited negative curvature at their edges. Over time, the pores grew to ∼100–160 nm in diameter after 60–90 min, with some pores measuring more than 300 nm. We confirmed these results using flow cytometry, which we used to monitor the release of fluorescent dextrans from isolated MOM vesicles. The dextran molecules were released gradually, in a manner constrained by pore size. However, the release rates were consistent over a range of dextran sizes (10–500 kDa). We concluded that the pores were not static but widened dramatically to release molecules of different sizes. Taken together, the data from cryo-EM and flow cytometry argue that Bax promotes MOMP by inducing the formation of large, growing pores through a mechanism involving membrane-curvature stress. The American Society for Cell Biology 2015-01-15 /pmc/articles/PMC4294680/ /pubmed/25411335 http://dx.doi.org/10.1091/mbc.E13-11-0638 Text en © 2015 Gillies et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0). “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society for Cell Biology. |
spellingShingle | Articles Gillies, Laura A Du, Han Peters, Bjoern Knudson, C. Michael Newmeyer, Donald D. Kuwana, Tomomi Visual and functional demonstration of growing Bax-induced pores in mitochondrial outer membranes |
title | Visual and functional demonstration of growing Bax-induced pores in mitochondrial outer membranes |
title_full | Visual and functional demonstration of growing Bax-induced pores in mitochondrial outer membranes |
title_fullStr | Visual and functional demonstration of growing Bax-induced pores in mitochondrial outer membranes |
title_full_unstemmed | Visual and functional demonstration of growing Bax-induced pores in mitochondrial outer membranes |
title_short | Visual and functional demonstration of growing Bax-induced pores in mitochondrial outer membranes |
title_sort | visual and functional demonstration of growing bax-induced pores in mitochondrial outer membranes |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4294680/ https://www.ncbi.nlm.nih.gov/pubmed/25411335 http://dx.doi.org/10.1091/mbc.E13-11-0638 |
work_keys_str_mv | AT gillieslauraa visualandfunctionaldemonstrationofgrowingbaxinducedporesinmitochondrialoutermembranes AT duhan visualandfunctionaldemonstrationofgrowingbaxinducedporesinmitochondrialoutermembranes AT petersbjoern visualandfunctionaldemonstrationofgrowingbaxinducedporesinmitochondrialoutermembranes AT knudsoncmichael visualandfunctionaldemonstrationofgrowingbaxinducedporesinmitochondrialoutermembranes AT newmeyerdonaldd visualandfunctionaldemonstrationofgrowingbaxinducedporesinmitochondrialoutermembranes AT kuwanatomomi visualandfunctionaldemonstrationofgrowingbaxinducedporesinmitochondrialoutermembranes |