title: The LYR protein Mzm1 functions in the insertion of the Rieske Fe/S protein in yeast mitochondria.
abstract: The assembly of the cytochrome bc(1) complex in Saccharomyces cerevisiae is shown to be conditionally dependent on a novel factor, Mzm1. Cells lacking Mzm1 exhibit a modest bc(1) defect at 30°C, but the defect is exacerbated at elevated temperatures. Formation of bc(1) is stalled in mzm1Δ cells at a late assembly intermediate lacking the Rieske iron-sulfur protein Rip1. Rip1 levels are markedly attenuated in mzm1Δ cells at elevated temperatures. Respiratory growth can be restored in the mutant cells by the overexpression of the Rip1 subunit. Elevated levels of Mzm1 enhance the stabilization of Rip1 through physical interaction, suggesting that Mzm1 may be an important Rip1 chaperone especially under heat stress. Mzm1 may function primarily to stabilize Rip1 prior to inner membrane (IM) insertion or alternatively to aid in the presentation of Rip1 to the inner membrane translocation complex for extrusion of the folded domain containing the iron-sulfur center.
authors.affiliation: University of Utah Health Sciences Center, Department of Medicine, Salt Lake City, UT 84132, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Atkinson
authors.forename: Pamela
authors.initials: P
authors.lastname: Smith
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Fox
authors.forename: Tie-Zhong
authors.initials: TZ
authors.lastname: Cui
authors.forename: Oleh
authors.initials: O
authors.lastname: Khalimonchuk
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Winge
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D014450:Electron Transport Complex III / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D024101:Mitochondrial Proteins; C037989:Rieske iron-sulfur protein; D029701:Saccharomyces cerevisiae Proteins; C568504:mitochondrial zinc maintenance protein 1, S cerevisiae; D014450:Electron Transport Complex III