Goldman Ramiro P, Jozefkowicz Cintia, Canessa Fortuna Agustina, Sutka Moira, Alleva Karina, Ozu Marcelo
Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Medicina, Instituto de Fisiología y Biofísica (IFIBIO Houssay), Laboratorio de Biomembranas, Universidad de Buenos Aires, Argentina.
Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Departamento de Fisicomatemática, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina.
FEBS Lett. 2017 Jun;591(11):1555-1565. doi: 10.1002/1873-3468.12671. Epub 2017 May 25.
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 BvTIP1;2 (TIP1) and BvPIP2;1 (PIP2) 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 TIP1 or PIP2. Our results indicate that TIP1 is a mechanosensitive aquaporin, whereas PIP2 is not. We found that a single exponential function between the osmotic permeability coefficient and the volumetric elastic modulus governs the mechanosensitivity of TIP1. Finally, homology modeling analysis indicates that putative residues involved in mechanosensitivity show different quantity and distribution in TIP1 and PIP2.
以往的研究表明水通道蛋白可作为机械敏感通道。然而，关于水通道蛋白机械敏感性的主要问题仍不清楚。在本研究中，我们对来自红甜菜（Beta vulgaris）的水通道蛋白BvTIP1;2（TIP1）和BvPIP2;1（PIP2）的机械敏感特性进行了表征。我们同时测量了表达TIP1或PIP2的去核卵母细胞在渗透反应过程中的力学行为和水转运速率。我们的结果表明，TIP1是一种机械敏感水通道蛋白，而PIP2不是。我们发现渗透渗透系数与体积弹性模量之间的单指数函数决定了TIP1的机械敏感性。最后，同源建模分析表明，参与机械敏感性的推定残基在TIP1和PIP2中的数量和分布不同。
