title: Activity of a KATP+ channel in Arum spadix mitochondria during thermogenesis.
abstract: This report demonstrates that mitochondria isolated from thermogenic Arum spadices possess an ATP-sensitive potassium channel--responsible for electrical potential (DeltaPsi) collapse and mitochondrial swelling--whose characteristics are similar to those previously described in pea and wheat mitochondria. In order to study the relationship between this K(ATP)(+) channel and the uncoupled respiration, linked to thermogenesis, K(+) transport activities were compared with those of mitochondria that were isolated from pea stems, soybean suspension cell cultures and Arum tubers. The channel from Arum spadices is highly active and its major features are (i) potassium flux is performed primarily in an inward-rectifying manner; (ii) the influx of K(+) is associated with a matrix volume increase in both energized and non-energized mitochondria; and (iii) its activity depends on the redox state of electron transport chain (ETC) and oxygen availability. In particular, this paper shows that the K(ATP)(+) channel is inwardly activated in parallel with the alternative oxidase (AO). The activation is linked to an ETC-oxidized state and to high oxygen consumption. The putative role of this K(ATP)(+) channel is discussed in relation to flowering of thermogenic Arum spadices.
authors.affiliation: Department of Biology and Plant Protection, Section of Plant Biology, University of Udine, Udine, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Petrussa
authors.forename: Valentino
authors.initials: V
authors.lastname: Casolo
authors.forename: Carlo
authors.initials: C
authors.lastname: Peresson
authors.forename: Jana
authors.initials: J
authors.lastname: Krajnáková
authors.forename: Francesco
authors.initials: F
authors.lastname: Macrì
authors.forename: Angelo
authors.initials: A
authors.lastname: Vianello
mesh_terms: D031058:Arum / Q000378:metabolism*; D004579:Electron Transport / Q000502:physiology; D035264:Flowers / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism*; D010101:Oxygen Consumption; D018526:Plant Transpiration / Q000187:drug effects; D015221:Potassium Channels / Q000378:metabolism*; D011190:Potassium Cyanide / Q000494:pharmacology; D013696:Temperature
chemical_list: D015221:Potassium Channels; C117780:mitochondrial K(ATP) channel; D011190:Potassium Cyanide