title: Comparison of the TIM and TOM channel activities of the mitochondrial protein import complexes.
abstract: Water-filled channels are central to the process of translocating proteins since they provide aqueous pathways through the hydrophobic environment of membranes. The Tom and Tim complexes translocate precursors across the mitochondrial outer and inner membranes, respectively, and contain channels referred to as TOM and TIM (previously called PSC and MCC). In this study, little differences were revealed from a direct comparison of the single channel properties of the TOM and TIM channels of yeast mitochondria. As they perform similar functions in translocating proteins across membranes, it is not surprising that both channels are high conductance, voltage-dependent channels that are slightly cation selective. Reconstituted TIM and TOM channel activities are not modified by deletion of the outer membrane channel VDAC, but are similarly affected by signal sequence peptides.
authors.affiliation: Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Veterinaria, Universidad de Extremadura, 10071 Cáceres, Spain.
authors.forename: Concepción
authors.initials: C
authors.lastname: Muro
authors.forename: Serguei M
authors.initials: SM
authors.lastname: Grigoriev
authors.forename: Dawn
authors.initials: D
authors.lastname: Pietkiewicz
authors.forename: Kathleen W
authors.initials: KW
authors.lastname: Kinnally
authors.forename: María Luisa
authors.initials: ML
authors.lastname: Campo
mesh_terms: D007425:Intracellular Membranes / Q000502:physiology*; D007473:Ion Channels / Q000145:classification* / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D008928:Mitochondria / Q000502:physiology*; D033681:Mitochondrial Membrane Transport Proteins / Q000145:classification* / Q000502:physiology*; D021382:Protein Sorting Signals / Q000502:physiology*; D021381:Protein Transport / Q000502:physiology; D015003:Yeasts / Q000502:physiology
chemical_list: D007473:Ion Channels; D033681:Mitochondrial Membrane Transport Proteins; D021382:Protein Sorting Signals