ATP-dependent silver transport across the basolateral membrane of rainbow trout gills
ATP-dependent silver transport across the basolateral membrane of rainbow trout gills
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DOI：
10.1006/taap.1999.8706
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发表时间：
1999-08-15
影响因子：
3.8
通讯作者：
Wood, CM
中科院分区：
文献类型：
--
作者：
Bury, NR;Grosell, M;Wood, CM
银已被证明对淡水硬骨鱼具有极高的毒性，由于鳃部 Na+/K+-ATP 酶活性失活，银会抑制鳃对 Na+ 的吸收。然而，鳃也是银进入鱼体内的一个途径。因此，本研究利用从淡水虹鳟鱼鳃中制备的基底外侧膜囊泡（BLMV），重点研究这种非必需金属穿过鳃细胞基底外侧膜的转运机制。 BLMV 对银的摄取是通过载体介导的过程进行的，该过程是 ATP 依赖性的，随着时间的推移达到平衡，并遵循 Michaelis-Menten 动力学，最大转运能力 (V-max) 为 14.3 +/- 5.5 (SE) nmol mg 膜蛋白(-1) min(-1)，亲和力 (K-m) 为 62.6 +/- 43.7 μM，并被 100 μM 钠抑制原钒酸盐（Na3VO4）。离子载体莫能菌素 (10 μM) 释放从 BLMV 转运的银。 104 kDa 大小的酰基磷酸中间体是在 ATP 加 Ag 存在的情况下由 BLMV 制剂形成的。这些结果表明，虹鳟鱼鳃的基底外侧膜中存在一种 P 型 ATP 酶，它可以主动转运银，这一过程会将这种重金属从其毒性作用部位——鳃中去除。 (C) 1999 年学术出版社。
Silver has been shown to be extremely toxic to freshwater teleosts, acting to inhibit Na+ uptake at the gills, due to the inactivation of branchial Na+/K+-ATPase activity. However, the gills are also a route by which silver may enter the fish. Therefore, this study focuses on the mechanism of transport of this nonessential metal across the basolateral membrane of the gill cell, using basolateral membrane vesicles (BLMV) prepared from the gills of freshwater rainbow trout. Uptake of silver by BLMV was via a carrier-mediated process, which was ATP-dependent, reached equilibium over time, and followed Michaelis-Menten kinetics, with maximal transport capacity (V-max) of 14.3 +/- 5.5 (SE) nmol mg membrane protein(-1) min(-1) and an affinity (K-m) of 62.6 +/- 43.7 mu M, and was inhibited by 100 mu M sodium orthovanadate (Na3VO4). The ionophore monensin (10 mu M) released transported silver from the BLMV. Acylphosphate intermediates, of a 104 kDa size, were formed from the BLMV preparations in the presence of ATP plus Ag. These results demonstrate that there is a P-type ATPase present in the basolateral membrane of the gills of rainbow trout that can actively transport silver, a process which will remove this heavy metal from its site of toxic action, the gill. (C) 1999 Academic Press.