title: Percolation and criticality in a mitochondrial network.
abstract: Synchronization of mitochondrial function is an important determinant of cell physiology and survival, yet little is known about the mechanism of interorganellar communication. We have recently observed that coordinated cell-wide oscillations in the mitochondrial energy state of heart cells can be induced by a highly localized perturbation of a few elements of the mitochondrial network, indicating that mitochondria represent a complex, self-organized system. Here, we apply percolation theory to explain the mechanism of intermitochondrial signal propagation in response to oxidative stress. A global phase transition (mitochondrial depolarization) is shown to occur when a critical density of mitochondria accumulate reactive oxygen species above a threshold to form an extended spanning cluster. The scaling and fractal properties of the mitochondrial network at the edge of instability agree remarkably well with the idea that mitochondria are organized as a percolation matrix, with reactive oxygen species as a key messenger.
authors.affiliation: Institute of Molecular Cardiobiology, The Johns Hopkins University, 720 Rutland Avenue, 844 Ross Building, Baltimore, MD 21205-2195, USA.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Aon
authors.forename: Sonia
authors.initials: S
authors.lastname: Cortassa
authors.forename: Brian
authors.initials: B
authors.lastname: O'Rourke
mesh_terms: D000818:Animals; D006168:Guinea Pigs; D008929:Mitochondria, Heart / Q000378:metabolism / Q000502:physiology*; D008954:Models, Biological; D009991:Oscillometry; D017382:Reactive Oxygen Species / Q000378:metabolism; D015290:Second Messenger Systems / Q000502:physiology; D013481:Superoxides / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D013481:Superoxides