Complex-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" display="inline" overflow="scroll"><mml:mi>L</mml:mi></mml:math>matrix and its recognition

Liu, Yue; Shan, Haiying

doi:10.1016/j.disc.2013.12.025

Cited by 1 publication

(1 citation statement)

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“…The isotonic MIB solution contained 15 g/L PVP in addition to 90 mM KCl, 10 mM NaCl, 2 mM MgCl 2 , 1.1 mM EGTA, 0.15 mM CaCl 2 , and 10 mM HEPES. Oocytes were extracted from the ovary cluster of an adult female frog (NASCO, Fort Atkinson, WI) and stored at 18 °C for less than three days prior to use.…”

Section: Methodsmentioning

confidence: 99%

Nanoscale Mechanism of Molecular Transport through the Nuclear Pore Complex As Studied by Scanning Electrochemical Microscopy

et al. 2013

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The nuclear pore complex (NPC) is the proteinaceous nanopore that solely mediates molecular transport across the nuclear envelope between the nucleus and cytoplasm of a eukaryotic cell. Small molecules (<40 kDa) diffuse through the large pore of this multiprotein complex. A passively impermeable macromolecule tagged with a signal peptide is chaperoned through the nanopore by nuclear transport receptors (e.g., importins) owing to their interactions with barrier-forming proteins. Presently, this bimodal transport mechanism is not well understood and is described by controversial models. Herein, we report on a dynamic and spatially resolved mechanism for NPC-mediated molecular transport through nanoscale central and peripheral routes with distinct permeabilities. Specifically, we develop a nanogap-based approach of scanning electrochemical microscopy to precisely measure the extremely high permeability of the nuclear envelope to a small probe molecule, (ferrocenylmethyl)trimethylammonium. Effective medium theories indicate that the passive permeability of 5.9 × 10−2 cm/s corresponds to the free diffusion of the probe molecule through ~22 nanopores with a radius of 24 nm and a length of 35 nm. Peripheral routes are blocked by wheat germ agglutinin to yield two-fold lower permeability for 17 nm-radius central routes. This lectin is also used in fluorescence assays to find that importins facilitate the transport of signal-tagged albumin mainly through the 7 nm-thick peripheral route rather than through the sufficiently large central route. We propose that this spatial selectivity is regulated by the conformational changes in barrier-forming proteins that transiently and locally expand the impermeably thin peripheral route while blocking the central route.

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Section: Methodsmentioning

confidence: 99%