WNK1 regulates phosphorylation of cation-chloride-coupled cotransporters via the STE20-related kinases, SPAK and OSR1
WNK1 regulates phosphorylation of cation-chloride-coupled cotransporters via the STE20-related kinases, SPAK and OSR1
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DOI：
10.1074/jbc.m510042200
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发表时间：
2005-12-30
影响因子：
4.8
通讯作者：
Shibuya, H
中科院分区：
文献类型：
--
作者：
Moriguchi, T;Urushiyama, S;Shibuya, H
WNK 1和WNK 4基因已被发现在一些患有由假性醛固酮减少症II型引起的高钾血症和高血压的患者中发生突变。假性醛固酮减少症II型的病理生理学线索是其对噻嗪类利尿剂的显著治疗反应，已知噻嗪类利尿剂可阻断氯化钠协同转运蛋白（NCC）。虽然这表明WNK 1在高血压中的作用，但精确的分子机制在很大程度上是未知的。在这里，我们已经表明，WNK 1磷酸化和调节STE 20相关的激酶，STE 20相关的脯氨酸-丙氨酸丰富的激酶（SPAK）和氧化应激反应1（OSR 1）。观察到WNK 1磷酸化位于SPAK和OSR 1激酶结构域之外的进化上保守的丝氨酸残基，OSR 1丝氨酸残基的突变导致OSR 1激酶活性增强。此外，低渗应激激活SPAK和OSR 1，并诱导保守的OSR 1丝氨酸残基的磷酸化，表明WNK 1可能是SPAK和OSR 1激酶的激活剂。此外，SPAK和OSR 1被发现直接磷酸化阳离子氯偶联的协同转运蛋白，包括NKCC 1，NKCC 2，和NCC的N-末端调控区。低渗应激可诱导细胞NCC磷酸化。这些结果表明，WNK 1和SPAK/OSR 1介导的低渗应激信号转导途径的转运蛋白，并可能提供洞察WNK 1调节离子平衡的机制。
The WNK1 and WNK4 genes have been found to be mutated in some patients with hyperkalemia and hypertension caused by pseudohypoaldosteronism type II. The clue to the pathophysiology of pseudohypoaldosteronism type II was its striking therapeutic response to thiazide diuretics, which are known to block the sodium chloride cotransporter (NCC). Although this suggests a role for WNK1 in hypertension, the precise molecular mechanisms are largely unknown. Here we have shown that WNK1 phosphorylates and regulates the STE20-related kinases, Ste20-related proline-alanine- rich kinase (SPAK) and oxidative stress response 1 (OSR1). WNK1 was observed to phosphorylate the evolutionary conserved serine residue located outside the kinase domains of SPAK and OSR1, and mutation of the OSR1 serine residue caused enhanced OSR1 kinase activity. In addition, hypotonic stress was shown to activate SPAK and OSR1 and induce phosphorylation of the conserved OSR1 serine residue, suggesting that WNK1 may be an activator of the SPAK and OSR1 kinases. Moreover, SPAK and OSR1 were found to directly phosphorylate the N-terminal regulatory regions of cation-chloride-coupled cotransporters including NKCC1, NKCC2, and NCC. Phosphorylation of NCC was induced by hypotonic stress in cells. These results suggested that WNK1 and SPAK/OSR1 mediate the hypotonic stress signaling pathway to the transporters and may provide insights into the mechanisms by which WNK1 regulates ion balance.