title: Membrane-integration characteristics of two ABC transporters, CFTR and P-glycoprotein.
abstract: To what extent do corresponding transmembrane helices in related integral membrane proteins have different membrane-insertion characteristics? Here, we compare, side-by-side, the membrane insertion characteristics of the 12 transmembrane helices in the adenosine triphosphate-binding cassette (ABC) transporters, P-glycoprotein (P-gp) and the cystic fibrosis transmembrane conductance regulator (CFTR). Our results show that 10 of the 12 CFTR transmembrane segments can insert independently into the ER membrane. In contrast, only three of the P-gp transmembrane segments are independently stable in the membrane, while the majority depend on the presence of neighboring loops and/or transmembrane segments for efficient insertion. Membrane-insertion characteristics can thus vary widely between related proteins.
authors.affiliation: Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Karl
authors.initials: K
authors.lastname: Enquist
authors.forename: Mawritz
authors.initials: M
authors.lastname: Fransson
authors.forename: Carolina
authors.initials: C
authors.lastname: Boekel
authors.forename: Inger
authors.initials: I
authors.lastname: Bengtsson
authors.forename: Karin
authors.initials: K
authors.lastname: Geiger
authors.forename: Lisa
authors.initials: L
authors.lastname: Lang
authors.forename: Aron
authors.initials: A
authors.lastname: Pettersson
authors.forename: Sofia
authors.initials: S
authors.lastname: Johansson
authors.forename: Gunnar
authors.initials: G
authors.lastname: von Heijne
authors.forename: IngMarie
authors.initials: I
authors.lastname: Nilsson
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018528:ATP-Binding Cassette Transporters / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001665:Binding Sites; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018528:ATP-Binding Cassette Transporters; C505032:CFTR protein, human; D011994:Recombinant Proteins; D019005:Cystic Fibrosis Transmembrane Conductance Regulator