Biosurfaces Lab, CIC biomaGUNE, San Sebastian, Spain
Dino Osmanović
London Centre for Nanotechnology, University College London, London, United Kingdom; Department of Physics and Astronomy, University College London, London, United Kingdom; Department of Physics, Bar-Ilan University, Ramat Gan, Israel; Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
Severin Ehret
Biosurfaces Lab, CIC biomaGUNE, San Sebastian, Spain
Carolina Araya Callis
Biosurfaces Lab, CIC biomaGUNE, San Sebastian, Spain
Steffen Frey
Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
Murray Stewart
Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
Changjiang You
Department of Biology, University of Osnabrück, Osnabrück, Germany
Dirk Görlich
Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
London Centre for Nanotechnology, University College London, London, United Kingdom; Department of Physics and Astronomy, University College London, London, United Kingdom
The permeability barrier of nuclear pore complexes (NPCs) controls bulk nucleocytoplasmic exchange. It consists of nucleoporin domains rich in phenylalanine-glycine motifs (FG domains). As a bottom-up nanoscale model for the permeability barrier, we have used planar films produced with three different end-grafted FG domains, and quantitatively analyzed the binding of two different nuclear transport receptors (NTRs), NTF2 and Importin β, together with the concomitant film thickness changes. NTR binding caused only moderate changes in film thickness; the binding isotherms showed negative cooperativity and could all be mapped onto a single master curve. This universal NTR binding behavior – a key element for the transport selectivity of the NPC – was quantitatively reproduced by a physical model that treats FG domains as regular, flexible polymers, and NTRs as spherical colloids with a homogeneous surface, ignoring the detailed arrangement of interaction sites along FG domains and on the NTR surface.
