USP10: the nexus between nexin and vasopressin.
USP10: the nexus between nexin and vasopressin.
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USP10：连接蛋白和加压素之间的联系。
DOI：
10.1152/ajprenal.90434.2008
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Johnson,JohnP
中科院分区：
文献类型：
--
作者：
Butterworth,MichaelB;Johnson,JohnP
从电生理学工具被肾脏生理学家使用的时候起，组织就被各种激素和药物化合物轰击，以研究它们在“盐和水运输”中的作用。抗利尿激素（ADH）对从青蛙皮肤、蟾蜍膀胱到兔肾小管的各种组织的作用的研究一致地证明了ADH（加压素）增加跨上皮钠转运的快速作用。随着时间的推移，这些早期的研究在细胞模型系统中得到了证实。上皮钠通道（ENaC）的顶端膜，以增加通道密度的易位似乎占，在很大程度上，增加钠转运。虽然已有证据表明细胞骨架在这一过程中发挥了作用，但其机制在很大程度上仍未得到描述。已经有一个形象的黑盒子连接加压素与其V2受体的结合，腺苷酸环化酶的激活和PKA的产生，在组织和细胞的顶端表面观察到ENaC密度的增加。在Boulkroun及其同事的工作中，黑盒子的盖子已经打开，以提供对所涉及的信号过程的复杂性的一瞥。该研究不仅描述了加压素依赖性蛋白表达的诱导，而且还将一种诱导蛋白与可能调节ENaC表面密度的机制联系起来。通过这种方式，作者揭示了细胞响应外部信号快速改变蛋白质表达并将该表达转化为行动的能力。一种去泛素化酶（DUB），USP 10，被发现可以通过应用加压素快速诱导。该研究的这一部分在源自小鼠皮质集合管并天然表达ENaC及其辅助和调节蛋白的细胞系中进行。最近，另外两种DUB，UCH-L3和USP 2 -45，已被证明在相同的细胞系中去泛素化ENaC（2，4）。正如预期的那样，在模型细胞系中USP 10与ENaC的外源性表达增加了ENaC表面密度。然而，与UCH-L3和USP 2 -45的作用不同，USP 10并没有通过改变ENaC本身的泛素化水平来改变ENaC的表面密度。通过进一步研究，作者试图确定这种加压素诱导的DUB的作用机制。利用酵母双杂交筛选，他们能够从细胞沼泽中找出USP 10的相互作用伴侣，并将DUB与分选连接蛋白3（SNX 3）联系起来。SNX 3似乎是USP 10的靶点，而ENaC不是，ENaC是通过SNX 3调节的。这建立了DUB与运输蛋白的复杂相互作用，该运输蛋白通过尚未定义的机制调节ENaC。这导致细胞膜上ENaC密度的增加和加压素对钠转运的增加，这在很多年前就在蟾蜍和青蛙中描述过。显然，在这一途径中还有其他参与者，其他DUB直接作用于ENaC或调节ENaC的蛋白质，但盖子已经打开。在这种研究中进行的基因组和蛋白质组学方法为细胞生理学家提供了新的工作工具，将我们对盐和水调节的理解带入了一个新时代。虽然相互作用的蛋白质网络有望是广泛的，我们有工具来开始确定这些激素信号级联的组件。目前的工作也加强了去泛素化在膜蛋白如离子通道的运输和表达调节中的新兴意义。
FROM THE TIME ELECTROPHYSIOLOGICAL tools became available to renal physiologists, tissues have been bombarded with a variety of hormones and pharmacological compounds to investigate their role in “salt and water transport.” The investigations into the actions of antidiuretic hormone (ADH) on a variety of tissues from frog skin and toad bladder to rabbit kidney tubules have consistently demonstrated the rapid action of ADH (vasopressin) to increase transepithelial sodium transport. Over time these early investigations were confirmed in cell model systems. The translocation of epithelial sodium channels (ENaC) to the apical membrane to increase channel density appears to account, in large part, for the increase in sodium transport. While it has been documented that the cytoskeleton plays a role in this process, the mechanisms remained largely undescribed. There has been a figurative black box linking the binding of vasopressin to its V2 receptor, activation of adenylate cyclase, and production of PKA, with the increase in ENaC density observed at the apical surface of tissues and cells. In the work presented by Boulkroun and colleagues (1), the lid of the black box has been opened to offer a glimpse into the complexities of the signaling processes involved. The study describes not only the induction of vasopressin-dependant protein expression but goes on to associate one of the induced proteins to machinery which may regulate ENaC surface density. In this way, the authors uncover the cell’s ability to rapidly alter the expression of proteins in response to external signals and translate that expression into action. A deubiquitinating enzyme (DUB), USP10, was found to be rapidly induced by the application of vasopressin. This component of the study was carried out in a cell line derived from mouse cortical collecting ducts and natively expressing ENaC and its accessory and regulatory proteins. Recently, two other DUBs, UCH-L3 and USP2-45, have been demonstrated to deubiquitinate ENaC in the same cell line (2, 4). As expected, exogenous expression of USP10 with ENaC in a model cell line increased ENaC surface density. However, unlike the action of UCH-L3 and USP2-45, USP10 did not alter ENaC surface density by changing the level of ubiquitination of ENaC itself. By taking their study a step further, the authors sought to identify the mechanism of action of this vasopressin-induced DUB. Employing a yeast two-hybrid screen, they were able to fish out USP10’s interacting partner from the cellular morass and link the DUB to sorting nexin 3 (SNX3). SNX3 appears to be a target for USP10 while ENaC is not, and it is through SNX3 that ENaC is regulated. What this sets up is a complicated interaction of a DUB with a trafficking protein which regulates ENaC by yet to be defined mechanisms. This results in the increase in ENaC density at the cell membrane and an increase in sodium transport by vasopressin, which was described so many years ago in toads and frogs. Clearly, there are other players in this pathway, other DUBs which act on ENaC directly or on proteins which regulate ENaC, but the lid has been opened. The genomic and proteomic approaches being undertaken in this kind of study give cell physiologists new tools with which to work, to take our understanding of salt and water regulation into a new era. While the web of interacting proteins promises to be extensive, we have the tools to begin identifying the components of these hormonal signaling cascades.The current work also reinforces the emerging significance of deubiquitination in the regulation of trafficking and expression of membrane proteins such as ion channels …