Tonoplast ( Bv Bv TIP TIP 1;2) and plasma membrane ( Bv Bv PIP PIP 2;1) aquaporins show different mechanosensitive properties

摘要

Previous works proposed that aquaporins behave as mechanosensitive channels. However, principal issues about mechanosensitivity of aquaporins are not known. In this work, we characterized the mechanosensitive properties of the water channels Bv TIP 1;2 ( TIP 1) and Bv PIP 2;1 ( PIP 2) from red beet ( Beta vulgaris ). We simultaneously measured the mechanical behavior and the water transport rates during the osmotic response of emptied‐out oocytes expressing TIP 1 or PIP 2. Our results indicate that TIP 1 is a mechanosensitive aquaporin, whereas PIP 2 is not. We found that a single exponential function between the osmotic permeability coefficient and the volumetric elastic modulus governs the mechanosensitivity of TIP 1. Finally, homology modeling analysis indicates that putative residues involved in mechanosensitivity show different quantity and distribution in TIP 1 and PIP 2.