Deciphering the ‘fuzzy’ interaction of FG nucleoporins and transport factors using SANS

Abstract

The largely intrinsically disordered phenylalanine-glycine-rich nucleoporins (FG Nups) underline a selectivity mechanism, which enables the rapid translocation of transport factors (TFs) through the nuclear pore complexes (NPCs). Conflicting models of NPC transport have assumed that FG Nups undergo different conformational transitions upon interacting with TFs. To selectively characterize conformational changes in FG Nups induced by TFs we performed small-angle neutron scattering (SANS) with contrast matching. Conformational ensembles derived SANS data indicate an increase in the overall size of FG Nups is associated with TF interaction. Moreover, the organization of the FG motif in the interacting state extends prior experimental analyses defining that FG motifs undergo conformational restriction upon interacting with TFs. These results provide structural insights into a highly dynamic interaction and illustrate how functional disorder imparts rapid and selective FG Nup – TF interactions. Support or Funding Information This work was supported by NIH GM117212(DC) and GM109824. This research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. Simulations used the Anton special-purpose supercomputer provided by the National Resource for Biomedical Supercomputing (NRBSC), the Pittsburgh Supercomputing Center (PSC), and the Biomedical Technology Research Center for Multiscale Modeling of Biological Systems (MMBioS) through Grant P41GM103712-S1 from the National Institutes of Health. D. E. Shaw Research generously made the Anton machine available. Simulations also used the XSEDE facilities supported by NSF ACI-105375. (A) Fit of best-performing sub-ensembles.(B) Plots of the Rg distribution compared with the initial pool of TraDES models (Black) for the SANS data indicated.(C) Weighted average Cα-Cα distance maps.(D) Conformers of the best-performing subensemble. Left, [2H]-FSFG-K, middle [2H]-FSFG-K + NTF2 (0.6 mM) (TraDES pool), (right) [2H]-FSFG-K + NTF2 (0.6 mM) with selection from the MD pool. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.