title: Transport pathways--proton motive force interrelationship in durum wheat mitochondria.
abstract: In durum wheat mitochondria (DWM) the ATP-inhibited plant mitochondrial potassium channel (PmitoK(ATP)) and the plant uncoupling protein (PUCP) are able to strongly reduce the proton motive force (pmf) to control mitochondrial production of reactive oxygen species; under these conditions, mitochondrial carriers lack the driving force for transport and should be inactive. However, unexpectedly, DWM uncoupling by PmitoK(ATP) neither impairs the exchange of ADP for ATP nor blocks the inward transport of Pi and succinate. This uptake may occur via the plant inner membrane anion channel (PIMAC), which is physiologically inhibited by membrane potential, but unlocks its activity in de-energized mitochondria. Probably, cooperation between PIMAC and carriers may accomplish metabolite movement across the inner membrane under both energized and de-energized conditions. PIMAC may also cooperate with PmitoK(ATP) to transport ammonium salts in DWM. Interestingly, this finding may trouble classical interpretation of in vitro mitochondrial swelling; instead of free passage of ammonia through the inner membrane and proton symport with Pi, that trigger metabolite movements via carriers, transport of ammonium via PmitoK(ATP) and that of the counteranion via PIMAC may occur. Here, we review properties, modulation and function of the above reported DWM channels and carriers to shed new light on the control that they exert on pmf and vice-versa.
authors.affiliation: Consiglio per la Ricerca e la sperimentazione in Agricoltura, Centro di Ricerca per la Cerealicoltura, S.S. 673 Km 25, 71122 Foggia, Italy. daniela.trono@entecra.it.
authors.forename: Daniela
authors.initials: D
authors.lastname: Trono
authors.affiliation: Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università di Foggia, Via Napoli 25, 71122 Foggia, Italy. maura.laus@unifg.it.
authors.forename: Maura N
authors.initials: MN
authors.lastname: Laus
authors.affiliation: Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università di Foggia, Via Napoli 25, 71122 Foggia, Italy. mario.soccio@unifg.it.
authors.forename: Mario
authors.initials: M
authors.lastname: Soccio
authors.affiliation: Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università di Foggia, Via Napoli 25, 71122 Foggia, Italy. donato.pastore@unifg.it.
authors.forename: Donato
authors.initials: D
authors.lastname: Pastore
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial; D008928:Mitochondria / Q000378:metabolism*; D000226:Mitochondrial ADP, ATP Translocases / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D015221:Potassium Channels / Q000378:metabolism; D018892:Proton-Motive Force; D017382:Reactive Oxygen Species / Q000378:metabolism; D014908:Triticum / Q000166:cytology / Q000378:metabolism*
chemical_list: D033681:Mitochondrial Membrane Transport Proteins; D010940:Plant Proteins; D015221:Potassium Channels; D017382:Reactive Oxygen Species; D000255:Adenosine Triphosphate; D000226:Mitochondrial ADP, ATP Translocases