title: Emery-Dreifuss muscular dystrophy mutations impair TRC40-mediated targeting of emerin to the inner nuclear membrane.
abstract: Emerin is a tail-anchored protein that is found predominantly at the inner nuclear membrane (INM), where it associates with components of the nuclear lamina. Mutations in the emerin gene cause Emery-Dreifuss muscular dystrophy (EDMD), an X-linked recessive disease. Here, we report that the TRC40/GET pathway for post-translational insertion of tail-anchored proteins into membranes is involved in emerin-trafficking. Using proximity ligation assays, we show that emerin interacts with TRC40 in situ. Emerin expressed in bacteria or in a cell-free lysate was inserted into microsomal membranes in an ATP- and TRC40-dependent manner. Dominant-negative fragments of the TRC40-receptor proteins WRB and CAML (also known as CAMLG) inhibited membrane insertion. A rapamycin-based dimerization assay revealed correct transport of wild-type emerin to the INM, whereas TRC40-binding, membrane integration and INM-targeting of emerin mutant proteins that occur in EDMD was disturbed. Our results suggest that the mode of membrane integration contributes to correct targeting of emerin to the INM.
authors.affiliation: Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Pfaff
authors.affiliation: Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany.
authors.forename: Jhon
authors.initials: J
authors.lastname: Rivera Monroy
authors.affiliation: Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany.
authors.forename: Cara
authors.initials: C
authors.lastname: Jamieson
authors.affiliation: Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany.
authors.forename: Kalpana
authors.initials: K
authors.lastname: Rajanala
authors.affiliation: Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany.
authors.forename: Fabio
authors.initials: F
authors.lastname: Vilardi
authors.affiliation: Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany Max-Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany blanche.schwappach@med.uni-goettingen.de rkehlen@gwdg.de.
authors.forename: Blanche
authors.initials: B
authors.lastname: Schwappach
authors.affiliation: Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany blanche.schwappach@med.uni-goettingen.de rkehlen@gwdg.de.
authors.forename: Ralph H
authors.initials: RH
authors.lastname: Kehlenbach
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D053501:Arsenite Transporting ATPases / Q000378:metabolism*; D045744:Cell Line, Tumor; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D008861:Microsomes / Q000378:metabolism; D020389:Muscular Dystrophy, Emery-Dreifuss / Q000235:genetics* / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*; D009685:Nuclear Envelope / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D011499:Protein Processing, Post-Translational / Q000235:genetics; D021381:Protein Transport / Q000235:genetics
chemical_list: C489667:GET3 protein, human; D008565:Membrane Proteins; D009687:Nuclear Proteins; C092710:emerin; D000255:Adenosine Triphosphate; D053501:Arsenite Transporting ATPases
keywords: CAML; Emerin; Inner nuclear membrane; TRC40; Tail-anchored protein; WRB