Modeled structural basis for the recognition of α2-3-sialyllactose by soluble Klotho.
Modeled structural basis for the recognition of α2-3-sialyllactose by soluble Klotho.
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可溶性 Klotho 识别 α2-3-唾液酸乳糖的建模结构基础。
DOI：
10.1096/fj.201700043r
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Huang,Chou-Long
中科院分区：
文献类型：
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作者：
Wright,JonD;An,Sung-Wan;Xie,Jian;Yoon,Joonho;Nischan,Nicole;Kohler,JenniferJ;Oliver,Noelynn;Lim,Carmay;Huang,Chou-Long
可溶性 Klotho (sKlotho) 是抗衰老膜 Klotho 的脱落胞外域，包含 2 个胞外结构域 KL1 和 KL2，每个结构域都与糖基水解酶具有序列同源性。 sKlotho 可引发多效性细胞反应，其作用机制尚不清楚。值得注意的是，在损伤情况下，sKlotho 通过下调心肌细胞和肾小球足细胞中的钙渗透性瞬时受体电位经典型亚型 6 (TRPC6) 通道来提供心脏和肾脏保护。抑制 TRPC6 PI3K 依赖性胞吐作用被认为是潜在机制，最近的研究表明 sKlotho 与脂筏中富含的含 α2-3-唾液酸乳糖的神经节苷脂相互作用，抑制脂筏依赖性 PI3K 信号传导。然而，sKlotho 结合和识别 α2-3-唾液酸乳糖的结构基础尚不清楚。使用同源建模和对接，我们鉴定了 KL1 结构域中可能参与结合唾液酸乳糖的关键蛋白质残基。基于 Klotho 下调 TRPC6 通道活性能力的功能实验证实了这些残基的重要性。此外，KL1 结构域结合 α2-3-唾液酸乳糖，下调 TRPC6 通道，并对小鼠应激诱导的心脏肥大发挥保护作用。我们的结果支持这样的观点，即唾液酸神经节苷脂和脂筏是 sKlotho 的膜受体，并且 KL1 结构域足以满足所测试的生物活性。这些发现可以帮助指导更简单的 Klotho 模拟物的设计。—Wright, J. D.、An, S.-W.、Xie, J.、Yoon, J.、Nischan, N.、Kohler, J. J.、Oliver, N.、Lim, C.、Huang, C.-L.可溶性 Klotho 识别 α2-3-唾液酸乳糖的建模结构基础。
Soluble Klotho (sKlotho) is the shed ectodomain of antiaging membrane Klotho that contains 2 extracellular domains KL1 and KL2, each of which shares sequence homology to glycosyl hydrolases. sKlotho elicits pleiotropic cellular responses with a poorly understood mechanism of action. Notably, in injury settings, sKlotho confers cardiac and renal protection by down-regulating calcium-permeable transient receptor potential canonical type isoform 6 (TRPC6) channels in cardiomyocytes and glomerular podocytes. Inhibition of PI3K-dependent exocytosis of TRPC6 is thought to be the underlying mechanism, and recent studies showed that sKlotho interacts with α2-3-sialyllactose-containing gangliosides enriched in lipid rafts to inhibit raft-dependent PI3K signaling. However, the structural basis for binding and recognition of α2-3-sialyllactose by sKlotho is unknown. Using homology modeling followed by docking, we identified key protein residues in the KL1 domain that are likely involved in binding sialyllactose. Functional experiments based on the ability of Klotho to down-regulate TRPC6 channel activity confirm the importance of these residues. Furthermore, KL1 domain binds α2-3-sialyllactose, down-regulates TRPC6 channels, and exerts protection against stress-induced cardiac hypertrophy in mice. Our results support the notion that sialogangliosides and lipid rafts are membrane receptors for sKlotho and that the KL1 domain is sufficient for the tested biologic activities. These findings can help guide the design of a simpler Klotho mimetic.—Wright, J. D., An, S.-W., Xie, J., Yoon, J., Nischan, N., Kohler, J. J., Oliver, N., Lim, C., Huang, C.-L. Modeled structural basis for the recognition of α2-3-sialyllactose by soluble Klotho.