Alexander R Todd, Grinstein Sergio
Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada, T6G 2R7.
J Exp Biol. 2009 Jun;212(Pt 11):1630-7. doi: 10.1242/jeb.027375.
NHE3 is a sodium-proton exchanger expressed predominantly in the apical membrane of renal and intestinal epithelia, where it plays a key role in salt and fluid absorption and pH homeostasis. It performs these functions through the exchange of luminal sodium for cytosolic protons. Acute regulation of NHE3 function is mediated by altering the total number of exchangers in the plasma membrane as well as their individual activity. Traffic between endomembrane and plasmalemmal pools of NHE3 dictates the density of exchangers available at the cell surface. The activity of the plasmalemmal pool, however, is not fixed and can be altered by the association with modifier proteins, by post-translational alterations (such as cAMP-mediated phosphorylation) and possibly also via interaction with specific plasmalemmal phospholipids. Interestingly, association with cytoskeletal components affects both levels of regulation, tethering NHE3 molecules at the surface and altering their intrinsic activity. This paper reviews the role of proteins and lipids in the modulation of NHE3 function.
NHE3是一种主要在肾和肠上皮细胞顶端膜表达的钠-质子交换体，它在盐和液体吸收以及pH稳态中起关键作用。它通过将管腔钠与胞质质子交换来执行这些功能。NHE3功能的急性调节是通过改变质膜中交换体的总数及其个体活性来介导的。NHE3在内膜池和质膜池之间的转运决定了细胞表面可用交换体的密度。然而，质膜池的活性不是固定的，可以通过与修饰蛋白的结合、翻译后修饰（如cAMP介导的磷酸化）以及可能还通过与特定质膜磷脂的相互作用来改变。有趣的是，与细胞骨架成分的结合会影响这两种调节水平，将NHE3分子 tethering 在表面并改变其内在活性。本文综述了蛋白质和脂质在调节NHE3功能中的作用。
原文中“tethering NHE3 molecules at the surface”中的“tethering”可能有误，推测可能是“targeting”，若按“targeting”翻译为“将NHE3分子靶向定位在表面”。请根据实际情况确认。
