Yun C H, Tse C M, Nath S K, Levine S A, Brant S R, Donowitz M
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Am J Physiol. 1995 Jul;269(1 Pt 1):G1-11. doi: 10.1152/ajpgi.1995.269.1.G1.
Na+/H+ exchangers are integral plasma membrane proteins that exchange extracellular Na+ for intracellular H+ with a stoichiometry of one for one. They are inhibitable by the diuretic amiloride and have multiple cellular functions, including intracellular pH homeostasis, cell volume control, and electroneutral NaCl absorption in epithelia. The presence of multiple forms of the exchangers was demonstrated by the recent cloning of four mammalian Na+/H+ exchangers, NHE1, NHE2, NHE3, and NHE4. All of these cloned Na+/H+ exchangers have 10-12 putative transmembrane helixes and a long cytoplasmic carboxyl domain. Despite the structural similarity, these Na+/H+ exchanger isoforms differ in their tissue distribution, kinetic characteristics, and response to external stimuli. The present review deals with the recent developments in the molecular identification of the Na+/H+ exchanger gene family, the functional characteristics, and the short-term regulation of Na+/H+ exchange at molecular and cellular levels.
钠氢交换体是整合在质膜上的蛋白质，以1:1的化学计量比将细胞外的钠离子与细胞内的氢离子进行交换。它们可被利尿药氨氯吡咪抑制，具有多种细胞功能，包括细胞内pH稳态、细胞体积控制以及上皮细胞中的电中性氯化钠吸收。最近克隆出四种哺乳动物钠氢交换体NHE1、NHE2、NHE3和NHE4，证明了存在多种形式的交换体。所有这些克隆出的钠氢交换体都有10 - 12个推定的跨膜螺旋和一个长的细胞质羧基结构域。尽管结构相似，但这些钠氢交换体亚型在组织分布、动力学特征和对外部刺激的反应方面存在差异。本综述涉及钠氢交换体基因家族分子鉴定、功能特性以及分子和细胞水平上钠氢交换短期调节的最新进展。
