Coupling of epithelial Na+ and Cl- channels by direct and indirect activation by serine proteases.
Coupling of epithelial Na+ and Cl- channels by direct and indirect activation by serine proteases.
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丝氨酸蛋白酶直接和间接激活上皮 Na 和 Cl 通道的偶联。
DOI：
10.1152/ajpcell.00395.2011
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Awayda,MouhamedS
中科院分区：
文献类型：
--
作者：
Gondzik,Veronika;Weber,WolfMichael;Awayda,MouhamedS
哺乳动物的集合管(CD)持续暴露在尿蛋白水解酶中。CD表达上皮性Na+通道(ENaC)，该通道被丝氨酸蛋白酶切割后激活。ENAC也以未被切割的形式存在于质膜上，使细胞外蛋白水解酶的激活成为调节Na+转运的重要机制。许多外源性和少量内源性胞外丝氨酸蛋白酶已被证明激活该通道。最近，激肽释放酶1(KLK1)被证明增加了天然CD中γENaC的裂解，这可能是这种内源性蛋白酶在Na+动态平衡中的直接作用。为了探索这一过程，我们检测了这种酶对极化的肾上皮细胞系(马丁达比犬肾)中Na+和Cl−运输的协调作用。我们还研究了天然尿蛋白水解酶在这一过程中的作用。短路电流(ISC)用来测量这些离子的输运。结果显示，依赖ENaC的Na+成分可被阿米洛利阻断，囊性纤维化跨膜电导调节因子依赖的Cl-−成分可被阻滞剂阻断。顶端应用胰酶(一种外源S1丝氨酸蛋白酶)可激活IENaC，但对ICFTR没有影响。枯草杆菌蛋白是一种外源性S8蛋白水解酶，可以模拟内源性呋喃类蛋白水解酶，激活这两种电流。KLK1和天然大鼠尿蛋白水解酶也有类似的激活。尿液中的蛋白水解酶在几分钟内被激活，其浓度与CD中的相似，这表明这一过程具有生理意义。ENAC的激活是不可逆的，并通过增强γ对ENaC的裂解来介导。CFTR的激活是间接的，可能依赖于内源性顶膜蛋白水解酶受体的激活。总之，这些数据显示了细胞外腔蛋白对肾上皮细胞中不同的Na+和Cl-−转运通路的协同刺激。它们还表明，基线尿蛋白水解酶活性足以改变这些上皮细胞中Na+和Cl−的运输。
The mammalian collecting duct (CD) is continuously exposed to urinary proteases. The CD expresses an epithelial Na+channel (ENaC) that is activated after cleavage by serine proteases. ENaC also exists at the plasma membrane in the uncleaved form, rendering activation by extracellular proteases an important mechanism for regulating Na+transport. Many exogenous and a small number of endogenous extracellular serine proteases have been shown to activate the channel. Recently, kallikrein 1 (KLK1) was shown to increase γENaC cleavage in the native CD indicating a possible direct role of this endogenous protease in Na+homeostasis. To explore this process, we examined the coordinated effect of this protease on Na+and Cl−transport in a polarized renal epithelial cell line (Madin-Darby canine kidney). We also examined the role of native urinary proteases in this process. Short-circuit current (Isc) was used to measure transport of these ions. TheIscexhibited an ENaC-dependent Na+component that was amiloride blockable and a cystic fibrosis transmembrane conductance regulator (CFTR)-dependent Cl−component that was blocked by inhibitor 172. Apical application of trypsin, an exogenous S1 serine protease, activatedIENaCbut was without effects onICFTR. Subtilisin an exogenous S8 protease that mimics endogenous furin-type proteases activated both currents. A similar activation was also observed with KLK1 and native rat urinary proteases. Activation with urinary proteases occurred within minutes and at protease concentrations similar to those in the CD indicating physiological significance of this process. ENaC activation was irreversible and mediated by enhanced cleavage of γENaC. The activation of CFTR was indirect and likely dependent on activation of an endogenous apical membrane protease receptor. Collectively, these data demonstrate coordinated stimulation of separate Na+and Cl−transport pathways in renal epithelia by extracellular luminal proteases. They also indicate that baseline urinary proteolytic activity is sufficient to modify Na+and Cl−transport in these epithelia.
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DOI：
10.1152/ajprenal.1999.277.2.f271
发表时间：
1999-08-01
影响因子：
4.2
作者：
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DOI：
10.1152/ajplung.00396.2004
发表时间：
2005-05
期刊：
American journal of physiology. Lung cellular and molecular physiology
影响因子：
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影响因子：
15.9
作者：
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DOI：
--
发表时间：
2007
期刊：
Purinergic Signalling Purinergic Signalling
影响因子：
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作者：
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DOI：
10.1152/ajpcell.00459.2010
发表时间：
2011
期刊：
American journal of physiology. Cell physiology
影响因子：
--
作者：
Gondzik,Veronika;Awayda,MouhamedS
通讯作者：
Awayda,MouhamedS