A regulatory role of polycystin-1 on cystic fibrosis transmembrane conductance regulator plasma membrane expression
A regulatory role of polycystin-1 on cystic fibrosis transmembrane conductance regulator plasma membrane expression
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DOI：
10.1159/000095133
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发表时间：
2006-01-01
影响因子：
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通讯作者：
Guggino, William B.
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文献类型：
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作者：
Ikeda, Masahiro;Fong, Peying;Guggino, William B.
常染色体显性多囊肾病 (ADPKD) 是由 PKD1 或 PKD2 基因突变引起的，PKD1 或 PKD2 分别编码多囊蛋白-1 (PC-1) 和多囊蛋白-2 (PC-2) 的基因。 ADPKD 的特征是形成多个进行性、充满液体的肾囊肿。为了阐明 ADPKD 囊肿分泌液体的机制，我们检测了 PC-1 对囊性纤维化跨膜电导调节因子 (CFTR)（一种关键的 Cl 分泌蛋白）质膜表达的影响。本研究使用了五个稳定转染的 MDCK 系：两个用空载体转染（对照细胞），三个表达人 PC-1（PC-1 细胞）。 PC-1 细胞中 cAMP 诱导的内源短路电流 (is) 小于对照细胞。与对照细胞相比，瞬时表达 pEGFP-CFTR 的 PC-1 细胞显示全细胞 cAMP 激活的 Cl 电流显着降低。细胞表面生物素化实验还表明，与对照相比，PC-1 细胞中 CFTR 的表面表达有所减少。此外，使用瞬时表达 PC-1 和 CFTR 的 CHO 细胞的研究表明，PC-1 COOH 末端在观察到的 CFTR 质膜表达减少中的重要性。 PC-1 和对照细胞之间未观察到内源 K+ 电流或 P2Y 受体反应存在差异，表明 PC-1 作用的特异性。这些结果表明PC-1选择性地维持CFTR的低细胞表面表达。此外，这些研究结果表明，PC-1 的故障会增强 CFTR 的质膜表达，从而导致 Cl- 异常分泌到囊肿腔中。版权所有 (c) 2006 S. Karger AG，巴塞尔。
Autosomal dominant polycystic kidney disease (ADPKD) is caused by genetic mutations in either PKD1 or PKD2, the genes that encode polycystin-1 (PC-1) and polycystin-2 (PC-2), respectively. ADPKD is characterized by the formation of multiple, progressive, fluid-filled renal cysts. To elucidate the mechanism of fluid secretion by ADPKD cysts, we examined the effect of PC-1 on the plasma membrane expression of cystic fibrosis transmembrane conductance regulator (CFTR), a key Cl- secretory protein. Five stably transfected MDCK lines were used in this study: two transfected with empty vector (control cells) and three expressing human PC-1 (PC-1 cells). The cAMP-induced endogenous short circuit currents (is) were smaller in PC-1 cells than in control cells. Compared to control cells, PC-1 cells transiently expressing pEGFP-CFTR showed significant reduction of whole cell cAMP-activated Cl-currents. Cell surface biotinylation experiments also indicated a reduction in surface expression of CFTR in PC-1 cells compared to control. Furthermore, studies using CHO cells transiently expressing PC-1 and CFTR suggest the importance of the PC-1 COOH-terminus in the observed reduction of CFTR plasma membrane expression. No differences in either endogeneous K+ currents or P2Y receptor responses were observed between PC-1 and control cells, indicating the specificity of PC-1's action. These results indicate that PC-1 selectively maintains low cell surface expression of CFTR. Moreover, these findings suggest that the malfunction of PC-1 enhances plasma membrane expression of CFTR, thus causing abnormal Cl- secretion into the cyst lumen. Copyright (c) 2006 S. Karger AG, Basel.