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      What is the mitochondrial permeability transition pore?

      1
      Journal of molecular and cellular cardiology
      Elsevier BV

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          Abstract

          Under conditions of mitochondrial calcium overload, especially when accompanied by oxidative stress, elevated phosphate concentrations and adenine nucleotide depletion, a non-specific pore, the mitochondrial permeability transition pore (MPTP), opens in the inner mitochondrial membrane. MPTP opening enables free passage into the mitochondria of molecules of <1.5 kDa including protons. The resulting uncoupling of oxidative phosphorylation leads to ATP depletion and necrotic cell death and it is now widely recognised that MPTP opening is a major cause of reperfusion injury and an effective target for cardioprotection. The properties of the MPTP are well defined, but despite extensive research in many laboratories, its exact molecular identity remains uncertain. Knockout studies have confirmed a role for cyclophilin-D (CyP-D), probably mediated by its peptidyl-prolyl cis-trans isomerase activity facilitating a conformational change of an inner membrane protein. However, the identity of the membrane component(s) remains controversial. Knockout studies have eliminated an essential role for either the voltage dependent anion channel (VDAC) or the adenine nucleotide translocase (ANT), although a regulatory role for the ANT was confirmed. Our own studies implicate the mitochondrial phosphate carrier (PiC) in MPTP formation and are consistent with a calcium-triggered conformational change of the PiC, facilitated by CyP-D, inducing pore opening. We propose that this is enhanced by an association of the PiC with the "c" conformation of the ANT. Agents that modulate pore opening may act on either or both the PiC and the ANT. However, knockdown and reconstitution studies are awaited to confirm or refute this model.

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          Author and article information

          Journal
          J Mol Cell Cardiol
          Journal of molecular and cellular cardiology
          Elsevier BV
          1095-8584
          0022-2828
          Jun 2009
          : 46
          : 6
          Affiliations
          [1 ] Department of Biochemistry and Bristol Heart Institute, University of Bristol, School of Medical Sciences, University Walk, Bristol, UK. A.Halestrap@Bristol.ac.uk
          Article
          S0022-2828(09)00098-4
          10.1016/j.yjmcc.2009.02.021
          19265700
          b5fe9859-0dd2-4b57-8065-b47dba45a86a
          History

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