2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/86571Channel proteins, that selectively conduct molecules across cell membranes, often exhibit an asymmetric structure. By means of a stochastic model, we argue that channel asymmetry in the presence of non-equilibrium fluctuations, fueled by the cell's metabolism as observed recently, can dramatically influence the transport through such channels by a ratchet-like mechanism. For an aquaglyceroporin that conducts water and glycerol we show that a previously determined asymmetric glycerol potential leads to enhanced inward transport of glycerol, but for unfavorably high glycerol concentrations also to enhanced outward transport that protects a cell against poisoning.REVTeX4, 4 pages, 3 figures; Accepted for publication in Phys. Rev. LettBiological PhysicsStatistical MechanicsBiomoleculestext