Identification of a multiprotein "motor" complex binding to water channel aquaporin-2
Identification of a multiprotein "motor" complex binding to water channel aquaporin-2
复制标题
DOI：
10.1016/j.bbrc.2005.03.079
复制
发表时间：
2005-05-20
影响因子：
3.1
通讯作者：
Sasaki, S
中科院分区：
文献类型：
--
作者：
Noda, Y;Saburo, HC;Sasaki, S
水通道水通道蛋白2 （AQP2）的定向定位严格调控机体水分稳态。转运AQP2到肾尖膜对肾集管中水的重吸收至关重要。最近，我们首次发现了直接与AQP2结合的蛋白：Rap1的gtpase激活蛋白SPA-1和细胞骨架蛋白actin。基于这些发现，我们推测存在包括AQP2、SPA-1和肌动蛋白在内的多蛋白复合物，为AQP2运输过程中产生力和运动提供了机制。为了明确构成该复合物的蛋白，利用免疫亲和柱偶联抗aqp2抗体，从大鼠肾乳头提取物中分离出大量aqp2相关蛋白复合物，并采用基质辅助激光解吸-电离飞行时间质谱（MALDI-TOF MS）进行分析。除SPA-I和肌动蛋白外，还使用该方法鉴定了I -I蛋白：离子钙结合接头分子2、肌球蛋白调节轻链平滑肌异构体2- a和2-b、α -原肌球蛋白5b、膜联蛋白A2和A6、scinderin、gelsolin、α -肌动蛋白4、α - ii谱蛋白和肌球蛋白重链非肌型a。我们的研究结果首次发现了一个与aqp2结合的多蛋白“发力”复合物。这种多蛋白复合物可能提供了驱动AQP2运动的机制。(c) 2005爱思唯尔公司版权所有。
Targeted positioning of water channel aquaporin-2 (AQP2) strictly regulates body water homeostasis. Trafficking of AQP2 to the apical membrane is critical to the reabsorption of water in renal collecting ducts. Recently, we have identified for the first time proteins which directly bind to AQP2: SPA-1, a GTPase-activating protein for Rap1, and cytoskeletal protein actin. Based on these findings, we have speculated the existence of a multiprotein complex which includes AQP2, SPA-1, and actin, for providing the mechanism which generates force and motion in AQP2 trafficking. To clarify the proteins comprising the complex, a large amount of AQP2-associated protein complex was isolated from the extract of rat kidney papilla using immunoaffinity column coupled with anti-AQP2 antibody and was analyzed by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS). In addition to SPA-I and actin, I I proteins were identified using this method: ionized calcium binding adapter molecule 2, myosin regulatory light chain smooth muscle isoforms 2-A and 2-B, alpha-tropomyosin 5b, annexin A2 and A6, scinderin, gelsolin, alpha-actinin 4, alpha-II spectrin, and myosin heavy chain nonmuscle type A. Our findings show for the first time an AQP2-binding multiprotein "force generator" complex. This multiprotein complex may provide the machinery of driving AQP2 movement. (c) 2005 Elsevier Inc. All rights reserved.