The Gating Mechanism of Yeast Aquaporin Studied by Molecular Dynamics Simulations

Monitoring the osmotic response of single yeast cells through force measurement in the environmental scanning electron microscope

“…To optimize each type of measurement, a soft cantilever can be used in the swelling experiments, while the indentation experiments would benefit from a cantilever of higher stiffness. Based on our results, this method is highly interesting for the screening of drugs directed toward the water transport activity of a single cell and for evaluating mechanosensitive regulation of aquaporin channels [4,5], for which a method has not been available before.…”

“…As potential targets for new drugs directed towards the cellular water transport, aquaporins and their function and regulation constitute an important field of study [2]. Yeast cells have been extensively used for production of recombinant aquaporins to high yields [3] and also as model systems to study cellular response to osmotic shock, where mechanosensitive regulation of yeast aquaporins related to the pressure or tension in the cell membrane has been suggested [4,5]. Studies of the osmotic response of yeast are usually performed on cells contained in an aqueous suspension using stopped-flow technique [4,5] or optical microscopy [4,6].…”

“…Yeast cells have been extensively used for production of recombinant aquaporins to high yields [3] and also as model systems to study cellular response to osmotic shock, where mechanosensitive regulation of yeast aquaporins related to the pressure or tension in the cell membrane has been suggested [4,5]. Studies of the osmotic response of yeast are usually performed on cells contained in an aqueous suspension using stopped-flow technique [4,5] or optical microscopy [4,6]. While the stopped-flow measurement gives an ensemble average of the response from the entire cell population, optical microscopy can be used to study the swelling of an individual cell.…”

Exploring the potential of water channels for developing MRI reporters and sensors without the need for exogenous contrast agents

“…To this end, we transduced cells with lentiviral vectors engineered to express six distinct water channels (Supplementary Fig. 2), chosen for their high permeability coefficients: human Aqp4 [37,38] (Homo sapiens) and killifish Aqp0 [39] (Fundulus heteroclitus); plant water channels, including BvPIP2;1 [40] (Beta vulgaris), NtPIP2;1 [41] (Nicotiana tabacum), and FaPIP2;1 [42] (Fragaria × ananassa); and yeast aquaporin Aqy1 from Saccharomyces cerevisiae (ScAqy1) [43], and Pichia pastoris (PpAqy1) [44]. In addition, we tested Nand C-terminal truncations of PpAqy1 and ScAqy1, specifically PpAqy1NΔ35 and ScAqy1CΔ21, which have been suggested to enhance water permeability relative to their fulllength counterparts through distinct mechanisms involving pore gating [44] and membrane trafficking [43].…”

“…2), chosen for their high permeability coefficients: human Aqp4 [37,38] (Homo sapiens) and killifish Aqp0 [39] (Fundulus heteroclitus); plant water channels, including BvPIP2;1 [40] (Beta vulgaris), NtPIP2;1 [41] (Nicotiana tabacum), and FaPIP2;1 [42] (Fragaria × ananassa); and yeast aquaporin Aqy1 from Saccharomyces cerevisiae (ScAqy1) [43], and Pichia pastoris (PpAqy1) [44]. In addition, we tested Nand C-terminal truncations of PpAqy1 and ScAqy1, specifically PpAqy1NΔ35 and ScAqy1CΔ21, which have been suggested to enhance water permeability relative to their fulllength counterparts through distinct mechanisms involving pore gating [44] and membrane trafficking [43]. Using diffusionweighted MRI, we found that hAqp4, Aqp0, and BvPIP2;1 displayed a statistically significant increase in diffusivity, ranging from a moderate elevation in BvPIP2;1 (ΔD/D o = 25.1 ± 4.7 %, Pvalue = 0.03, n > 5) to a more substantial rise in hAqp4 (ΔD/D o = 67.1 ± 11.6 %, P-value = 0.008, n = 3) (Fig.…”