title: Distinct domains of small Tims involved in subunit interaction and substrate recognition.
abstract: Tim9 and Tim10 belong to the small Tim family of mitochondrial ATP-independent chaperones. They are organised in a specific hetero-oligomeric complex (TIM10) that escorts polytopic proteins into the mitochondrial inner membrane. The contributions of the individual subunits to the assembly and function of the TIM10 complex remain poorly understood. Here, we show that substrate recognition and assembly of the complex are mediated by distinct domains of the subunits. These are unrelated to the characteristic "twin CX3C" motif that is present in all small Tims and ensures proper folding of the unassembled subunits. Specifically, we show that substrate recognition is achieved by the Tim10 subunit, whilst Tim9 serves a more structural role. The N-terminal domain of Tim10 is a substrate sensor whilst its C-terminal part is essential for complex formation. By contrast, both N and C-terminal domains of Tim9 are involved in the stability of the complex.
authors.affiliation: Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK.
authors.forename: Maïlys A S
authors.initials: MA
authors.lastname: Vergnolle
authors.forename: Catherine
authors.initials: C
authors.lastname: Baud
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Golovanov
authors.forename: Felicity
authors.initials: F
authors.lastname: Alcock
authors.forename: Pierre
authors.initials: P
authors.lastname: Luciano
authors.forename: Lu-Yun
authors.initials: LY
authors.lastname: Lian
authors.forename: Kostas
authors.initials: K
authors.lastname: Tokatlidis
mesh_terms: D001483:Base Sequence; D004271:DNA, Fungal / Q000235:genetics; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D046912:Multiprotein Complexes; D019906:Nuclear Magnetic Resonance, Biomolecular; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020349:Surface Plasmon Resonance
chemical_list: D004271:DNA, Fungal; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins; D046912:Multiprotein Complexes; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; C107250:TIM10 protein, S cerevisiae; C116366:Tim9 protein, S cerevisiae