title: Mode of membrane insertion of individual transmembrane segments in Mdl1 and Mdl2, multi-spanning mitochondrial ABC transporters.
abstract: The sorting of an individual transmembrane (TM) segment of multi-spanning membrane proteins by the TIM23 complex in the mitochondrial inner membrane is poorly understood. Using the Mgm1 fusion approach, we attempted to assess the membrane insertion of individual TM segments of Mdl1p and Mdl2p, mitochondrial ABC transporters. Although these transporters share high sequence similarity, our results show that their membrane sorting patterns differ and that specific residues in TM domains strongly influence membrane insertion or translocation. These data imply that TIM23-mediated membrane insertion highly depends on the TM domain sequence context.
authors.affiliation: School of Biological Sciences, Seoul National University, Seoul 151-747, South Korea.
authors.forename: Kwangjin
authors.initials: K
authors.lastname: Park
authors.affiliation: School of Biological Sciences, Seoul National University, Seoul 151-747, South Korea.
authors.forename: Sung-Jun
authors.initials: SJ
authors.lastname: Jung
authors.affiliation: School of Biological Sciences, Seoul National University, Seoul 151-747, South Korea.
authors.forename: Hyeonseong
authors.initials: H
authors.lastname: Kim
authors.affiliation: School of Biological Sciences, Seoul National University, Seoul 151-747, South Korea. Electronic address: joy@snu.ac.kr.
authors.forename: Hyun
authors.initials: H
authors.lastname: Kim
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D033681:Mitochondrial Membrane Transport Proteins / Q000737:chemistry / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000378:metabolism; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; C490069:MDL1 protein, S cerevisiae; C490070:MDL2 protein, S cerevisiae; D033681:Mitochondrial Membrane Transport Proteins; D029701:Saccharomyces cerevisiae Proteins
keywords: Conservative sorting; Import; Mgm1; Mitochondria; Stop-transfer; TIM23