Ismailov I I, Berdiev B K, Fuller C M, Bradford A L, Lifton R P, Warnock D G, Bubien J K, Benos D J
Department of Physiology and Biophysics, University of Alabama at Birmingham, USA.
Am J Physiol. 1996 Jan;270(1 Pt 1):C214-23. doi: 10.1152/ajpcell.1996.270.1.C214.
Hypertension is a multifactorial disorder that results in an increased risk of cardiovascular and end-stage renal disease. Liddle's disease represents a specific hypertensive disease and expresses itself in the human population as an autosomal dominant trait. Recent experimental evidence indicates that patients with Liddle's disease have constitutively active amiloride-sensitive Na+ channels and that these channels are phenotypically expressed in lymphocytes obtained from normal and affected members of the original Liddle's kindred. Linkage analysis indicates that this disease results from a deletion of the carboxy-terminal region of the beta-subunit of a recently cloned epithelial Na+ channel (ENaC). We report the successful immunopurification and reconstitution of both normal and constitutively active lymphocyte Na+ channels into planar lipid bilayers. These channels display all of the characteristics typical of renal Na+ channels, including sensitivity to protein kinase A phosphorylation. We demonstrate that gating of normal Na+ channels is removed by cytoplasmic trypsin digestion and that the constitutively active Liddle's Na+ channels are blocked by a beta- or gamma-ENaC carboxy-terminal peptide in a GTP-dependent fashion.
高血压是一种多因素疾病，会增加患心血管疾病和终末期肾病的风险。利德尔病是一种特殊的高血压疾病，在人群中表现为常染色体显性性状。最近的实验证据表明，利德尔病患者具有组成型活性氨氯地平敏感钠通道，并且这些通道在从原始利德尔家族的正常和患病成员获取的淋巴细胞中表型表达。连锁分析表明，该疾病是由最近克隆的上皮钠通道（ENaC）β亚基羧基末端区域的缺失引起的。我们报告了成功地将正常和组成型活性淋巴细胞钠通道免疫纯化并重建到平面脂质双分子层中。这些通道表现出肾钠通道的所有典型特征，包括对蛋白激酶A磷酸化的敏感性。我们证明，正常钠通道的门控可通过细胞质胰蛋白酶消化去除，并且组成型活性利德尔钠通道可被β或γ-ENaC羧基末端肽以GTP依赖的方式阻断。
