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Plasticity of an ultrafast interaction between nucleoporins and nuclear transport receptors.


Type

Article

Change log

Authors

Milles, Sigrid 
Mercadante, Davide 
Aramburu, Iker Valle 
Jensen, Malene Ringkjøbing 
Banterle, Niccolò 

Abstract

The mechanisms by which intrinsically disordered proteins engage in rapid and highly selective binding is a subject of considerable interest and represents a central paradigm to nuclear pore complex (NPC) function, where nuclear transport receptors (NTRs) move through the NPC by binding disordered phenylalanine-glycine-rich nucleoporins (FG-Nups). Combining single-molecule fluorescence, molecular simulations, and nuclear magnetic resonance, we show that a rapidly fluctuating FG-Nup populates an ensemble of conformations that are prone to bind NTRs with near diffusion-limited on rates, as shown by stopped-flow kinetic measurements. This is achieved using multiple, minimalistic, low-affinity binding motifs that are in rapid exchange when engaging with the NTR, allowing the FG-Nup to maintain an unexpectedly high plasticity in its bound state. We propose that these exceptional physical characteristics enable a rapid and specific transport mechanism in the physiological context, a notion supported by single molecule in-cell assays on intact NPCs.

Description

Keywords

Active Transport, Cell Nucleus, Crystallography, X-Ray, Fluorescence Resonance Energy Transfer, Humans, Karyopherins, Models, Molecular, Nuclear Pore Complex Proteins, Nuclear Proteins, Saccharomyces cerevisiae

Journal Title

Cell

Conference Name

Journal ISSN

0092-8674
1097-4172

Volume Title

163

Publisher

Elsevier BV
Sponsorship
Wellcome Trust (095195/Z/10/Z)
We are grateful for helpful comments and various discussions with Cedric Debes, Martin Beck as well as the whole Lemke group. We thank Guillaume Bouvignies for help with relaxation dispersion experiments, and Damien Maurin for sample preparation. S.M. acknowledges funding from the Boehringer Ingelheim Fonds (BIF) and an EMBO long-term fellowship (ALTF 468-2014) and EC (EMBOCOFUND2012, GA-2012-600394) via Marie Curie Action. I.V.A. acknowledges a BIF short-term fellowship. J.C. and S.L.S. are supported by the Wellcome Trust. J.C. is a Wellcome Trust Senior Research Fellow (WT/095195). E.A.L. is grateful to funds from the SFB1129 and the Emmy Noether program of the DFG, F.G. from the Klaus Tschira Foundation, and D.M. from the BIOMS program of Heidelberg University. We are also grateful to instrument access via the EMBL Pepcore facility.