title: Structural basis for the interaction between NTF2 and nucleoporin FxFG repeats.
abstract: Interactions with nucleoporins containing FxFG-repeat cores are crucial for the nuclear import of RanGDP mediated by nuclear transport factor 2 (NTF2). We describe here the 1.9 A resolution crystal structure of yeast NTF2-N77Y bound to a FxFG-nucleoporin core, which provides a basis for understanding this interaction and its role in nuclear trafficking. The two identical FxFG binding sites on the dimeric molecule are formed by residues from each chain of NTF2. Engineered mutants at the interaction interface reduce the binding of NTF2 to nuclear pores and cause reduced growth rates and Ran mislocalization when substituted for the wild-type protein in yeast. Comparison with the crystal structure of FG-nucleoporin cores bound to importin-beta and TAP/p15 identified a number of common features of their binding sites. The structure of the binding interfaces on these transport factors provides a rationale for the specificity of their interactions with nucleoporins that, combined with their weak binding constants, facilitates rapid translocation through NPCs during nuclear trafficking.
authors.affiliation: MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Bayliss
authors.forename: Sara W
authors.initials: SW
authors.lastname: Leung
authors.forename: Rosanna P
authors.initials: RP
authors.lastname: Baker
authors.forename: B Booth
authors.initials: BB
authors.lastname: Quimby
authors.forename: Anita H
authors.initials: AH
authors.lastname: Corbett
authors.forename: Murray
authors.initials: M
authors.lastname: Stewart
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D019281:Dimerization; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry* / Q000378:metabolism; D029543:Nucleocytoplasmic Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D016415:Sequence Alignment
chemical_list: D002352:Carrier Proteins; D005656:Fungal Proteins; D028861:Nuclear Pore Complex Proteins; D029543:Nucleocytoplasmic Transport Proteins; C503612:Nutf2 protein, rat; D010455:Peptides