title: N-tail translocation in a eukaryotic polytopic membrane protein: synergy between neighboring transmembrane segments.
abstract: We have used the natural N-glycosylation site in the N-tail of cig30, a eukaryotic polytopic membrane protein, as a marker for N-tail translocation across the microsomal membrane. Analysis of C-terminally truncated cig30 constructs reveals that the first transmembrane segment is sufficient for translocation of the wild-type N-tail; in contrast, in a mutant with four arginines introduced into the N-tail the second transmembrane segment is also required for efficient N-tail translocation. Our observations imply a non-sequential assembly mechanism in which the ultimate location of the N-tail relative to the membrane may depend on more than one transmembrane segment.
authors.affiliation: Department of Biochemistry, Stockholm University, Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Monné
authors.forename: G
authors.initials: G
authors.lastname: Gafvelin
authors.forename: R
authors.initials: R
authors.lastname: Nilsson
authors.forename: G
authors.initials: G
authors.lastname: von Heijne
mesh_terms: D000123:Acetyltransferases; D000818:Animals; D001665:Binding Sites; D004285:Dogs; D000081031:Fatty Acid Elongases; D006031:Glycosylation; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008861:Microsomes / Q000378:metabolism; D009154:Mutation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D011994:Recombinant Proteins; D000123:Acetyltransferases; D000081031:Fatty Acid Elongases