Nitric oxide and atrial natriuretic factor stimulate cGMP-dependent membrane insertion of aquaporin 2 in renal epithelial cells
Nitric oxide and atrial natriuretic factor stimulate cGMP-dependent membrane insertion of aquaporin 2 in renal epithelial cells
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DOI：
10.1172/jci9594
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发表时间：
2000-11-01
影响因子：
15.9
通讯作者：
Brown, D
中科院分区：
文献类型：
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作者：
Bouley, R;Breton, S;Brown, D
在集合管主细胞中，水通道蛋白2(AQP2)在加压素(VP)刺激下从细胞内的小泡穿梭到质膜。VP激活腺酰环化酶，增加细胞内cAMP，激活蛋白激酶A(PKA)，使COOH末端残基丝氨酸256上的AQP2磷酸化。利用大鼠肾脏切片和稳定表达AQP2的LLC-PK1细胞(LLC-AQP2细胞)，我们现在证明了AQP2的转运可以通过cAMP不依赖的途径来刺激。在这些系统中，一氧化氮(NO)供体硝普钠和NONOate以及NO合成酶底物L精氨酸模拟VP的作用，刺激水通道蛋白P2从细胞质小泡重新定位到质膜。与VP不同的是，这些药物不会增加细胞内cAMP。然而，SNP增加细胞内cGMP，外源cGMP刺激AQP2膜插入。通过cGMP传递信号的心钠素也刺激AQP2易位。Vp和SNP的作用可被激酶抑制剂H89阻断。在表达磷酸化缺陷突变体256SerAla-AQP2的LLC-PK1细胞中，SNP不能刺激AQP2的膜插入，这表明信号转导需要Ser256的磷酸化。在体外，PKA和cGMP依赖的蛋白激酶G都能使该COOH末端残基上的AQP2磷酸化。这些结果证明了AQP2膜插入肾上皮细胞的一种新的、cAMP不依赖和cGMP依赖的途径。
In collecting duct principal cells, aquaporin 2 (AQP2) is shuttled from intracellular Vesicles to the plasma membrane upon vasopressin (VP) stimulation. VP activates adenylyl cyclase, increases intracellular cAMP, activating protein kinase A (PKA) to phosphorylate AQP2 on the COOH-terminal residue, serine 256. Using rat kidney slices and LLC-PK1 cells stably expressing AQP2 (LLC-AQP2 cells), we now show that AQP2 trafficking can be stimulated by cAMP-independent pathways. In these systems, the nitric oxide (NO) donors sodium nitroprusside (SNP) and NONOate and the NO synthase substrate L-arginine mimicked the effect of VP, stimulating relocation of AQP2 from cytoplasmic vesicles to the plasma membrane. Unlike VP, these other agents did not increase intracellular cAMP. However, SNP increased intracellular cGMP, and exogenous cGMP stimulated AQP2-membrane insertion. Atrial natriuretic factor, which signals via cGMP, also stimulated AQP2 translocation. The VP and SNP effects were blocked by the kinase inhibitor H89. SNP did not stimulate membrane insertion of AQP2 in LLC-PK1 cells expressing the phosphorylation-deficient mutant 256SerAla-AQP2, indicating that phosphorylation of Ser256 is required for signaling. Both PKA and cGMP-dependent protein kinase G phosphorylated AQP2 on this COOH-terminal residue in vitro. These results demonstrate a novel, cAMP-independent and cGMP-dependent pathway for AQP2 membrane insertion in renal epithelial cells.