title: Calcium Flux across Plant Mitochondrial Membranes: Possible Molecular Players.
abstract: Plants, being sessile organisms, have evolved the ability to integrate external stimuli into metabolic and developmental signals. A wide variety of signals, including abiotic, biotic, and developmental stimuli, were observed to evoke specific spatio-temporal Ca(2+) transients which are further transduced by Ca(2+) sensor proteins into a transcriptional and metabolic response. Most of the research on Ca(2+) signaling in plants has been focused on the transport mechanisms for Ca(2+) across the plasma- and the vacuolar membranes as well as on the components involved in decoding of cytoplasmic Ca(2+) signals, but how intracellular organelles such as mitochondria are involved in the process of Ca(2+) signaling is just emerging. The combination of the molecular players and the elicitors of Ca(2+) signaling in mitochondria together with newly generated detection systems for measuring organellar Ca(2+) concentrations in plants has started to provide fruitful grounds for further discoveries. In the present review we give an updated overview of the currently identified/hypothesized pathways, such as voltage-dependent anion channels, homologs of the mammalian mitochondrial uniporter (MCU), LETM1, a plant glutamate receptor family member, adenine nucleotide/phosphate carriers and the permeability transition pore (PTP), that may contribute to the transport of Ca(2+) across the outer and inner mitochondrial membranes in plants. We briefly discuss the relevance of the mitochondrial Ca(2+) homeostasis for ensuring optimal bioenergetic performance of this organelle.
authors.affiliation: Department of Biology, University of Padova Padova, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Carraretto
authors.affiliation: Department of Biology, University of PadovaPadova, Italy; Department of Biomedical Sciences, University of PadovaPadova, Italy.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Checchetto
authors.affiliation: Department of Biology, University of Padova Padova, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: De Bortoli
authors.affiliation: Department of Biology, University of PadovaPadova, Italy; Department of Life Science and Biotechnology, University of FerraraFerrara, Italy.
authors.forename: Elide
authors.initials: E
authors.lastname: Formentin
authors.affiliation: Department of Biosciences, University of MilanMilan, Italy; CNR, Institute of Biophysics, Consiglio Nazionale delle RicercheMilan, Italy.
authors.forename: Alex
authors.initials: A
authors.lastname: Costa
authors.affiliation: Department of Biology, University of PadovaPadova, Italy; CNR, Institute of NeurosciencesPadova, Italy.
authors.forename: Ildikó
authors.initials: I
authors.lastname: Szabó
authors.affiliation: Department of Biology, University of PadovaPadova, Italy; CNR, Institute of NeurosciencesPadova, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Teardo
keywords: calcium channels and transporters; calcium homeostasis; higher plants; mitochondria; physiological processes