title: Toxic PRnpoly-dipeptides encoded by theC9orf72repeat expansion block nuclear import and export.
abstract: The toxic proline:arginine (PRn) poly-dipeptide encoded by the (GGGGCC)nrepeat expansion in theC9orf72form of heritable amyotrophic lateral sclerosis (ALS) binds to the central channel of the nuclear pore and inhibits the movement of macromolecules into and out of the nucleus. The PRnpoly-dipeptide binds to polymeric forms of the phenylalanine:glycine (FG) repeat domain, which is shared by several proteins of the nuclear pore complex, including those in the central channel. A method of chemical footprinting was used to characterize labile, cross-β polymers formed from the FG domain of the Nup54 protein. Mutations within the footprinted region of Nup54 polymers blocked both polymerization and binding by the PRnpoly-dipeptide. The aliphatic alcohol 1,6-hexanediol melted FG domain polymers in vitro and reversed PRn-mediated enhancement of the nuclear pore permeability barrier. These data suggest that toxicity of the PRnpoly-dipeptide results in part from its ability to lock the FG repeats of nuclear pore proteins in the polymerized state. Our study offers a mechanistic interpretation of PRnpoly-dipeptide toxicity in the context of a prominent form of ALS.
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390.
authors.forename: Kevin Y
authors.initials: KY
authors.lastname: Shi
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390.
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Mori
authors.affiliation: Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218.
authors.forename: Zehra F
authors.initials: ZF
authors.lastname: Nizami
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390.
authors.forename: Yi
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390.
authors.forename: Masato
authors.initials: M
authors.lastname: Kato
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390.
authors.forename: Siheng
authors.initials: S
authors.lastname: Xiang
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390.
authors.forename: Leeju C
authors.initials: LC
authors.lastname: Wu
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390.
authors.forename: Ming
authors.initials: M
authors.lastname: Ding
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390.
authors.forename: Yonghao
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218.
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Gall
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390 Steven.McKnight@UTSouthwestern.edu.
authors.forename: Steven L
authors.initials: SL
authors.lastname: McKnight
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000818:Animals; D001704:Biopolymers; D000073885:C9orf72 Protein / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D042622:DNA Repeat Expansion / Q000235:genetics*; D004151:Dipeptides / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D006018:Glycols / Q000494:pharmacology; D006801:Humans; D018613:Microscopy, Confocal; D022022:Nuclear Pore / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D009865:Oocytes / Q000648:ultrastructure; D010539:Permeability / Q000187:drug effects; D011485:Protein Binding; D000072417:Protein Domains; D014909:Wheat Germ Agglutinins / Q000378:metabolism / Q000494:pharmacology; D014982:Xenopus laevis
chemical_list: D001704:Biopolymers; D000073885:C9orf72 Protein; C568651:C9orf72 protein, human; D004151:Dipeptides; D006018:Glycols; D028861:Nuclear Pore Complex Proteins; C465451:Nup98 protein, human; D014909:Wheat Germ Agglutinins; C027765:hexamethylene glycol
keywords: C9orf72 repeat expansion; FG domain; PRn poly-dipeptide; labile cross-β polymers; nuclear pore