Vasopressin rapidly increases phosphorylation of UT-A1 urea transporter in rat IMCDs through PKA.
Vasopressin rapidly increases phosphorylation of UT-A1 urea transporter in rat IMCDs through PKA.
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DOI：
10.1152/ajprenal.0054.2001
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Chi Zhang;J. Sands;J. Klein
中科院分区：
文献类型：
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作者：
Chi Zhang;J. Sands;J. Klein
UT-A1尿素转运蛋白在维持内髓高渗环境中起重要作用。加压素在5-10分钟内增加大鼠终末内髓集合管（IMCD）的尿素渗透性。为了阐明其机制，IMCD悬浮液用[（32）P]正磷酸盐进行放射性标记。UT-A1免疫沉淀，并通过放射自显影和Western印迹分析。97-和117-kDa的UT-A1蛋白都被磷酸化。加压素治疗增加了两个UT-A1蛋白的磷酸化在2分钟，在5-10分钟达到峰值，并保持升高长达30分钟。有一个明显的增加与10 pM和50%的增加与10-100 nM加压素的UT-A1磷酸化。1-脱氨基-8-D-精氨酸加压素（dDAVP）或8-（4-氯苯硫基）-cAMP（CPT-cAMP）也增加UT-A1磷酸化。加压素刺激的UT-A1磷酸化的增加被H-89或蛋白激酶A的特异性肽抑制剂阻断。磷酸酶抑制剂（冈田酸，calyculin）增加UT-A1磷酸化。我们得出结论，加压素增加UT-A1磷酸化通过蛋白激酶A在2-5分钟内在大鼠IMCD。这表明UT-A1的磷酸化可能是加压素在体内快速增加尿素渗透性的机制。
The UT-A1 urea transporter plays an important role in maintaining the hyperosmolar milieu of the inner medulla. Vasopressin increases urea permeability in rat terminal inner medullary collecting ducts (IMCDs) within 5-10 min. To elucidate the mechanism, IMCD suspensions were radiolabeled with [(32)P]orthophosphate. UT-A1 was immunoprecipitated and analyzed by autoradiogram and Western blot. Both the 97- and 117-kDa UT-A1 proteins were phosphorylated. Vasopressin treatment increased the phosphorylation of both UT-A1 proteins at 2 min, which peaked at 5-10 min and remained elevated for up to 30 min. There was a discernable increase in UT-A1 phosphorylation with 10 pM and a 50% increase with 10-100 nM vasopressin. 1-Desamino-8-D-arginine vasopressin (dDAVP) or 8-(4-chlorophenylthio)-cAMP (CPT-cAMP) also increased UT-A1 phosphorylation. The vasopressin-stimulated increase in UT-A1 phosphorylation was blocked by H-89 or a specific peptide inhibitor of protein kinase A. Phosphatase inhibitors (okadaic acid, calyculin) increased UT-A1 phosphorylation. We conclude that vasopressin increases UT-A1 phosphorylation via protein kinase A within 2-5 min in rat IMCDs. This suggests that phosphorylation of UT-A1 may be the mechanism by which vasopressin rapidly increases urea permeability in vivo.