Plasticity of an Ultrafast Interaction between Nucleoporins and Nuclear Transport Receptors
Sigrid Milles 8, Davide Mercadante 8, Iker Valle Aramburu 8, Malene Ringkjøbing Jensen, Niccolò Banterle, Christine Koehler, Swati Tyagi, Jane Clarke, Sarah L. Shammas, Martin Blackledge correspondence email, Frauke Gräter correspondence email, Edward A. Lemke correspondence email
8 Co-first author
Publication stage: In Press Corrected Proof
Open Access
Highlights
•Integrative structural biology reveals the basis of rapid nuclear transport
•Transient binding of disordered nucleoporins leaves their plasticity unaffected
•Multiple minimalistic low-affinity binding motifs create a polyvalent complex
•A highly reactive and dynamic surface permits an ultrafast binding mechanism
Summary
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.
This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Received: June 25, 2015; Received in revised form: August 17, 2015; Accepted: September 23, 2015; Published Online: October 08, 2015
© 2015 The Authors. Published by Elsevier Inc.
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