水通道的分子生物学研究

The Molecular Blology Studles of Water Channels

水通道是哺乳动物及植物细胞膜上转运水的特异孔道。第一个水通道蛋白即原型分子水通道（２８ｋＤ通道构成整合膜蛋白）的ｃＤＮＡ序列是在１９９１年完成鉴定的。目前从哺乳动物组织中已鉴定出至少五种水通道蛋白，统称为水蛋白（ａｑｕａｐｏｒｉｎ，ＡＱＰ），均属于主体内在蛋白（ＭＩＰ）家族的成员。水通道介导水依渗透梯度方向运动。不同的水通道蛋白在组织中的分布不同，但多在肾髓质有表达。原型分子水通道蛋白在膜中以四聚体形式存在，每一单体形成一个功能性的水孔道。

Water channels are the aqueous pores in the plasma membranes of mammalian and plant tissue cells,The cDNA sequence of the first water channel protein(AQP-CHIP)was reported in 1991.Up to date ,at least five mammalian water channels are identified and referred to as the “aquaporin”(AQP).AQPs the members of major intrinsic protein(MIP)family. Channel-mediated water transport permits the movement of water in the direction of an osmotic gradient.The distribution of AQPs are in many tissues and most of them are expressed in the renal medulla.AQP-CHIP assembles into homotetramers in the plasma membrane and each CHIP monomer appears to form a functional water pore.