Structure and function of the Permeability Transition Pore (PTP) in plant mitochondria

Mitochondria are multifunctional organelles with a crucial role in bioenergetics, being the major generators of ATP in the cell. The energetic machinery is responsible for a tightly controlled process, but in some cases it can encounter a sudden disruption through the opening of the mitochondrial permeability transition pore (PTP). The identity of PTP has not been completely unravelled yet, and it represents one of the most elusive topics in cell biology. The current idea is that PTP coincides with mitochondrial proteins of major importance, preserved through evolution. In the controversial scenario of molecular attributions for PTP, F-ATP synthase dimers were recently suggested and proved to be one strong candidate for the PTP in mammals, yeast and flies. This work aims to investigate if this model could also be applied to plant mitochondria, where no evidence has been collected so far. In this scenario, F-ATP synthase might represent an enzyme with multiple functions: shaping mitochondrial cristae architecture, sustaining life through ATP production and becoming also a permeability system, hence controlling life and death processes. In this ‘three-paper dissertation’ we reviewed the literature on PTP in plants, collected new evidence on permeability transition (PT) and PTP in isolated pea mitochondria and established a novel methodology for monitoring ATP levels and dynamics with the fluorescent protein sensor ATeam