Department of Chemistry, University Federico II of Naples, Naples, Italy.
FEBS Lett. 2010 Dec 1;584(23):4797-801. doi: 10.1016/j.febslet.2010.10.058. Epub 2010 Nov 2.
Aquaporin-0 (AQP0) is the major integral membrane protein of lens fiber cell and helps to maintain lens transparency by mediating inter-cell adhesion. To shed light on the unexpected higher water transport efficiency of killifish AQP0 as compared to mammalian orthologues, we performed a comparative analysis of all available AQP0 sequences and built 3D-models for representatives of different vertebrate classes. The analysis shows that air-living organisms evolved specific mutations at pore-lining positions to modulate the AQP0 water transport efficiency while maintaining the correct tertiary/quaternary arrangement to allow the formation of "thin junctions" between lens fiber cells. We conclude that the low permeability of mammalian AQP0 is required not to promote cell adhesion, but to modulate the water balance in a dry environment.
水通道蛋白 0（AQP0）是晶状体纤维细胞的主要完整膜蛋白，通过介导细胞间黏附有助于维持晶状体透明度。为了阐明与哺乳动物同源物相比，弹涂鱼 AQP0 出人意料的更高水运输效率，我们对所有可用的 AQP0 序列进行了比较分析，并为不同脊椎动物类群的代表构建了 3D 模型。分析表明，在空气呼吸的生物中，特定的突变出现在孔衬里位置，以调节 AQP0 的水运输效率，同时保持正确的三级/四级排列，以允许在晶状体纤维细胞之间形成“薄连接”。我们的结论是，哺乳动物 AQP0 的低通透性不是促进细胞黏附所必需的，而是在干燥环境中调节水平衡所必需的。
