Ca(2+) influx via store-operated Ca(2+) release activated Ca(2+) (CRAC) channels represents a main signaling pathway for T-cell activation as well as mast-cell degranulation. The ER-located Ca(2+)-sensor, STIM1 and the Ca(2+)-selective ion pore, Orai1 in the membrane are sufficient to fully reconstitute CRAC currents. Their identification, but even more the recent structural resolution of both ...

In previous chapters, the synthesis of a highly hydrogen selective membrane formed by the deposition of a silica layer on top of a Vycor glass substrate was discussed. In this chapter, the preparation of a composite membrane using a porous alumina support is described. This membrane showed a high hydrogen permeance of the order of 10 mol m s Pa at 873 K with selectivity of hydrogen over CH4, CO...

OBJECTIVES The purpose of this study was to investigate the permeation of the low-volatile solvent limonene through different disposable, unlined, unsupported, nitrile exam whole gloves (blue, purple, sterling, and lavender, from Kimberly-Clark). METHODS This study utilized a moving and static dextrous robot hand as part of a novel dynamic permeation system that allowed sampling at specific t...

Ion channels catalyze ionic permeation across membranes via water-filled pores. To understand how changes in intracellular magnesium concentration regulate the influx of Mg2+ into cells, we examine early events in the relaxation of Mg2+ channel CorA toward its open state using massively-repeated molecular dynamics simulations conducted either with or without regulatory ions. The pore of CorA co...

We report a strong coupling between permeation and gating in a mutant NMDA channel (NR1 N598Q-NR2A). The channel opens to two states that differ by their conductance and, surprisingly, by their selectivity for two permeant monovalent cations, Na+ and Cs+. The two open states are linked to the closed state via a cyclic gating reaction that proceeds preferentially in one direction under biionic c...

Recent determination of the molecular structures of potassium andmechanosensitive channels from x-ray crystallography has led to arenewed interest in ion channels. The challenge for permeation modelsis to understand the functional properties of channels from the availablestructural information. Here we give a critical review of the three maincontenders, namely, continuum theories, Brownian dyna...

Voltage-gated ion channels sense voltage by shuttling arginine residues located in the S4 segment across the membrane electric field. The molecular pathway for this arginine permeation is not understood, nor is the filtering mechanism that permits passage of charged arginines but excludes solution ions. We find that substituting the first S4 arginine with smaller amino acids opens a high-conduc...

OBJECTIVES Microvascular invasion and microlymphatic permeation are indicators of microscopic tumour invasion into small vessels and have been considered to be powerful prognostic indicators for non-small-cell lung cancer (NSCLC). Several studies have suggested that these should be included in the TNM classification, but, there have been conflicting results regarding the prognostic impact of mi...

TRPV5 is unique within the large TRP channel family for displaying a high Ca2+ selectivity together with Ca2+-dependent inactivation. Our study aims to uncover novel insights into channel gating through in-depth structure-function analysis. We identify an exceptional tryptophan (W583) at the terminus of the intracellular pore that is unique for TRPV5 (and TRPV6). A combination of site-directed ...

The voltage sensor domain (VSD) is the key module for voltage sensing in voltage-gated ion channels and voltage-sensing phosphatases. Structurally, both the VSD and the recently discovered voltage-gated proton channels (Hv channels) voltage sensor only protein (VSOP) and Hv1 contain four transmembrane segments. The fourth transmembrane segment (S4) of Hv channels contains three periodically ali...