Intersectin links WNK kinases to endocytosis of ROMK1
Intersectin links WNK kinases to endocytosis of ROMK1
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DOI：
10.1172/jci30087
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发表时间：
2007-04-01
影响因子：
15.9
通讯作者：
Huang, Chou-Long
中科院分区：
文献类型：
--
作者：
He, Guocheng;Wang, Hao-Ran;Huang, Chou-Long
无赖氨酸（WNK）激酶是一类新的蛋白激酶家族，其特征在于催化赖氨酸的非典型位置。2个家族成员WNK 1和WNK 4的突变导致2型假性醛固酮减少症（PHA2），这是一种常染色体显性疾病，以高血压和高钾血症为特征。WNK 1和WNK 4刺激肾外髓钾1（ROMK 1）的网格蛋白依赖性内吞作用，并且引起WNK 4的PHA 2突变增加内吞作用。WNK如何刺激ROMK 1的内吞作用以及WNK 4的突变如何增加内吞作用尚不清楚。Intersectin（ITSN）是一种多模块内吞支架蛋白。在这里，我们表明WNK 1和WNK 4与ITSN相互作用，并且这种相互作用对于WNK刺激ROMK 1的内吞作用至关重要。WNK 1和WNK 4对ROMK 1的内吞作用的刺激需要WNK特异性的富含脯氨酸的基序，但不需要它们的激酶活性。WNK 4与ROMK 1以及ITSN相互作用。致病WNK 4突变增强了WNK 4与ITSN和ROMK 1的相互作用，导致ROMK 1的内吞作用增加。这些结果为WNK激酶刺激ROMK 1内吞提供了分子机制。
With-no-lysine (WNK) kinases are a novel family of protein kinases characterized by an atypical placement of the catalytic lysine. Mutations of 2 family members, WNK1 and WNK4, cause pseudohypoaldosteronism type 2 (PHA2), an autosomal-dominant disease characterized by hypertension and hyperkalemia. WNK1 and WNK4 stimulate clathrin-dependent endocytosis of renal outer medullar potassium 1 (ROMK1), and PHA2-causing mutations of WNK4 increase the endocytosis. How WNKs stimulate endocytosis of ROMK1 and how mutations of WNK4 increase the endocytosis are unknown. Intersectin (ITSN) is a multimodular endocytic scaffold protein. Here we show that WNK1 and WNK4 interacted with ITSN and that the interactions were crucial for stimulation of endocytosis of ROMK1 by WNKs. The stimulation of endocytosis of ROMK1 by WNK1 and WNK4 required specific proline-rich motifs of WNKs, but did not require their kinase activity. WNK4 interacted with ROMK1 as well as with ITSN. Disease-causing WNK4 mutations enhanced interactions of WNK4 with ITSN and ROMK1, leading to increased endocytosis of ROMK1. These results provide a molecular mechanism for stimulation of endocytosis of ROMK1 by WNK kinases.