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Mitochondria and cell death

Doran, E.; Halestrap, A. P.; Doran (nee Udovikova), Olena; Gillespie, J. P.; O'Toole, A.

Authors

E. Doran

A. P. Halestrap

Olena Doran Olena.Doran@uwe.ac.uk
College Dean of Research and Enterprise

J. P. Gillespie

A. O'Toole



Abstract

Mitochondria play a central role in both apoptosis and necrosis through the opening of the mitochondrial permeability transition pore (MPTP). This is thought to be formed through a Ca2+-triggered conformational change of the adenine nucleotide translocase (ANT) bound to matrix cyclophilin-D and we have now demonstrated this directly by reconstitution of the pure components. Opening of the MPTP causes swelling and uncoupling of mitochondria which, unrestrained, leads to necrosis. In ischaemia/reperfusion injury of the heart we have shown MPTP opening directly. Recovery of hearts correlates with subsequent closure, and agents that prevent opening or enhance closure protect from injury. Transient MPTP opening may also be involved in apoptosis by initially causing swelling and rupture of the outer membrane to release cytochrome c (cyt c), which then activates the caspase cascade and sets apoptosis in motion. Subsequent MPTP closure allows ATP levels to be maintained, ensuring that cell death remains apoptotic rather than necrotic. Apoptosis in the hippocampus that occurs after a hypoglycaemic or ischaemic insult is triggered by this means. Other apoptotic stimuli such as cytokines or removal of growth factors also involve mitochondrial cyt c release, but here there is controversy over whether the MPTP is involved. In many cases cyt c release is seen without any mitochondrial depolarization, suggesting that the MPTP does not open. Recent data of our own and others have revealed a specific outer-membrane cyt c-release pathway involving porin that does not release other intermembrane proteins such as adenylate kinase. This is opened by pro-apototic members of the Bcl-2 family such as BAX and prevented by anti-apoptotic members such as Bcl-x(L). Our own data suggest that this pathway may interact directly with the ANT in the inner membrane at contact sites.

Citation

Doran, E., Halestrap, A. P., Doran (nee Udovikova), O., Gillespie, J. P., & O'Toole, A. (2000). Mitochondria and cell death. Biochemical Society Transactions, 28(2), 170-177. https://doi.org/10.1042/bst0280170

Journal Article Type Conference Paper
Publication Date Jan 1, 2000
Journal Biochemical Society Transactions
Print ISSN 0300-5127
Publisher Portland Press
Peer Reviewed Peer Reviewed
Volume 28
Issue 2
Pages 170-177
DOI https://doi.org/10.1042/bst0280170
Keywords mitochondria, apoptosis
Public URL https://uwe-repository.worktribe.com/output/1095292
Publisher URL http://dx.doi.org/10.1042/bst0280170
Related Public URLs http://www.ncbi.nlm.nih.gov/pubmed/10816121
Additional Information Corporate Creators : Bristol University