Physiology of the volume-sensitive/regulatory anion channel VSOR/VRAC. Part 1: from its discovery and phenotype characterization to the molecular entity identification

Table 1 Phenotypes of the properties of VSOR/VRAC

A. Physiological properties
Cell volume sensitivity	Activation by cell swelling (volume expansion) but not directly by mechano-stress
Cytosolic ATP dependence	Non-hydrolytic requirement of intracellular ATP
Cytosolic Mg²⁺ sensitivity	Sensitivity to intracellular free Mg²⁺
B. Biophysical properties
Single-channel level	Intermediate outwardly rectifying unitary conductance under symmetrical Cl⁻ conditions : 10–40 pS at negative potentials 30–80 pS at positive potentials at physiological Cl⁻ concentrations
Whole-cell current level
Voltage dependence	Moderate outward rectification Inactivation kinetics at large positive potentials Open-channel blocking by extracellular ATP
Anion selectivity	Low-field anion selectivity: Eisenman type I sequence : I⁻ > Br⁻ > Cl⁻

ISSN: 1880-6562