title: 'Natively unfolded' nucleoporins in nucleocytoplasmic transport: clustered or evenly distributed?
abstract: The nuclear pore complex (NPC) acts as a selective gate that mediates the bidirectional transport of macromolecules between the cytoplasm and the nucleus of eukaryotic cells. 'Natively unfolded' nucleoporins (Nups) with domains rich in phenylalanine-glycine (FG) repeats form the selective permeability barrier and provide binding sites for mobile transport receptors in the NPC. Understanding the structure and function of the FG-Nups barrier under real-time trafficking conditions is still a formidable challenge due to the dynamic nature of a channeled membranous environment. Recently, we have shown that three-dimensional (3D) density maps of transient interactions between the FG-Nups barrier and a cargo-free or a cargo-bound transport receptor in native NPCs can be obtained by an advanced single-molecule fluorescence microscopy approach. Moreover, we found that these interaction sites are spatially clustered into distinct groups in the periphery around a central axial channel with a diameter of approximately 10-20 nm in the NPC. The 3D distribution of interaction sites may indicate some native properties of the FG-Nups barrier. Here we speculate that the selective permeability barrier in the NPC could be formed by clustered FG-Nups.
authors.affiliation: Department of Biological Sciences, Center for Photochemical Sciences, Bowling Green State University, OH, USA. wyang@bgsu.edu
authors.forename: Weidong
authors.initials: W
authors.lastname: Yang
mesh_terms: D021581:Active Transport, Cell Nucleus; D002467:Cell Nucleus / Q000378:metabolism; D005998:Glycine / Q000737:chemistry; D022022:Nuclear Pore / Q000378:metabolism; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry / Q000378:metabolism*; D010649:Phenylalanine / Q000737:chemistry; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D021381:Protein Transport
chemical_list: D028861:Nuclear Pore Complex Proteins; D010649:Phenylalanine; D005998:Glycine