High-resolution x-ray structure of human aquaporin 5
High-resolution x-ray structure of human aquaporin 5
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DOI：
10.1073/pnas.0801466105
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发表时间：
2008-09-09
影响因子：
11.1
通讯作者：
Neutze, Richard
中科院分区：
文献类型：
--
作者：
Horsefield, Rob;Norden, Kristina;Neutze, Richard
人体水通道蛋白5 （HsAQP5）促进水在质膜上的运输，已经在胃、十二指肠、胰腺、气道、肺、唾液腺、汗腺、眼睛、泪腺和内耳的细胞中被发现。与AQP2一样，AQP5也受到磷酸化的翻译后调控，此时它在细胞内储存室和质膜之间运输。关于膜运输的分子机制细节尚不清楚。本文报道了HsAQP5在2.0埃分辨率下的x射线结构，并强调了与其他真核水通道蛋白的结构异同。脂质堵塞了假定的中心孔，阻止气体或离子通过四聚体的中心。在结构中观察到多个一致的磷酸化位点，并讨论了它们的潜在调节作用。我们假设C末端构象的改变可能是由AQP5的磷酸化引起的，从而信号运输。
Human aquaporin 5 (HsAQP5)facilitates the transport of water across plasma membranes and has been identified within cells of the stomach, duodenum, pancreas, airways, lungs, salivary glands, sweat glands, eyes, lacrimal glands, and the inner ear. AQP5, like AQP2, is subject to posttranslational regulation by phosphorylation, at which point it is trafficked between intracellular storage compartments and the plasma membrane. Details concerning the molecular mechanism of membrane trafficking are unknown. Here we report the x-ray structure of HsAQP5 to 2.0-angstrom resolution and highlight structural similarities and differences relative to other eukaryotic aquaporins. A lipid occludes the putative central pore, preventing the passage of gas or ions through the center of the tetramer. Multiple consensus phosphorylation sites are observed in the structure and their potential regulatory role is discussed. We postulate that a change in the conformation of the C terminus may arise from the phosphorylation of AQP5 and thereby signal trafficking.