title: The Permeability Transition in Plant Mitochondria: The Missing Link.
abstract: The synthesis of ATP in mitochondria is dependent on a low permeability of the inner membrane. Nevertheless, mitochondria can undergo an increased permeability to solutes, named permeability transition (PT) that is mediated by a permeability transition pore (PTP). PTP opening requires matrix Ca(2+) and leads to mitochondrial swelling and release of intramembrane space proteins (e.g., cytochrome c). This feature has been initially observed in mammalian mitochondria and tentatively attributed to some components present either in the outer or inner membrane. Recent works on mammalian mitochondria point to mitochondrial ATP synthase dimers as physical basis for PT, a finding that has been substantiated in yeast and Drosophila mitochondria. In plant mitochondria, swelling and release of proteins have been linked to programmed cell death, but in isolated mitochondria PT has been observed in only a few cases and in plant cell cultures only indirect evidence is available. The possibility that mitochondrial ATP synthase dimers could function as PTP also in plants is discussed here on the basis of the current evidence. Finally, a hypothetical explanation for the origin of PTP is provided in the framework of molecular exaptation.
authors.affiliation: Plant Biology Unit, Department of Agricultural and Environmental Sciences, University of Udine Udine, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Zancani
authors.affiliation: Plant Biology Unit, Department of Agricultural and Environmental Sciences, University of Udine Udine, Italy.
authors.forename: Valentino
authors.initials: V
authors.lastname: Casolo
authors.affiliation: Plant Biology Unit, Department of Agricultural and Environmental Sciences, University of Udine Udine, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Petrussa
authors.affiliation: Plant Biology Unit, Department of Agricultural and Environmental Sciences, University of Udine Udine, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Peresson
authors.affiliation: Plant Biology Unit, Department of Agricultural and Environmental Sciences, University of Udine Udine, Italy.
authors.forename: Sonia
authors.initials: S
authors.lastname: Patui
authors.affiliation: Plant Biology Unit, Department of Agricultural and Environmental Sciences, University of Udine Udine, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Bertolini
authors.affiliation: Plant Biology Unit, Department of Agricultural and Environmental Sciences, University of Udine Udine, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: De Col
authors.affiliation: Plant Biology Unit, Department of Agricultural and Environmental Sciences, University of Udine Udine, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Braidot
authors.affiliation: Plant Biology Unit, Department of Agricultural and Environmental Sciences, University of Udine Udine, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Boscutti
authors.affiliation: Plant Biology Unit, Department of Agricultural and Environmental Sciences, University of Udine Udine, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Vianello
keywords: ATP synthase; environmental stress; exaptation; permeability transition; plant mitochondria