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昆明COP15翻开全球生物多样性保护新篇章 快报文章
资源环境快报,2021年第20期
作者:  董利苹
Microsoft Word(22Kb)  |  收藏  |  浏览/下载:750/1  |  提交时间:2021/10/31
Kunming Declaration  Ecological Civilization  a Shared Future for All Life on Earth  
国际组织为减少人与野生动物冲突发起全球号召 快报文章
资源环境快报,2021年第14期
作者:  董利苹
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A Future for All  Human-Wildlife Coexistence  
A lower X-gate in TASK channels traps inhibitors within the vestibule 期刊论文
NATURE, 2020
作者:  Chen, Tao;  Nomura, Kinya;  Wang, Xiaolin;  Sohrabi, Reza;  Xu, Jin;  Yao, Lingya;  Paasch, Bradley C.;  Ma, Li;  Kremer, James;  Cheng, Yuti;  Zhang, Li;  Wang, Nian;  Wang, Ertao;  Xin, Xiu-Fang;  He, Sheng Yang
收藏  |  浏览/下载:64/0  |  提交时间:2020/07/03

TWIK-related acid-sensitive potassium (TASK) channels-members of the two pore domain potassium (K-2P) channel family-are found in neurons(1), cardiomyocytes(2-4) and vascular smooth muscle cells(5), where they are involved in the regulation of heart rate(6), pulmonary artery tone(5,7), sleep/wake cycles(8) and responses to volatile anaesthetics(8-11). K-2P channels regulate the resting membrane potential, providing background K+ currents controlled by numerous physiological stimuli(12-15). Unlike other K-2P channels, TASK channels are able to bind inhibitors with high affinity, exceptional selectivity and very slow compound washout rates. As such, these channels are attractive drug targets, and TASK-1 inhibitors are currently in clinical trials for obstructive sleep apnoea and atrial fibrillation(16). In general, potassium channels have an intramembrane vestibule with a selectivity filter situated above and a gate with four parallel helices located below  however, the K-2P channels studied so far all lack a lower gate. Here we present the X-ray crystal structure of TASK-1, and show that it contains a lower gate-which we designate as an '  X-gate'  -created by interaction of the two crossed C-terminal M4 transmembrane helices at the vestibule entrance. This structure is formed by six residues ((VLRFMT248)-V-243) that are essential for responses to volatile anaesthetics(10), neurotransmitters(13) and G-protein-coupled receptors(13). Mutations within the X-gate and the surrounding regions markedly affect both the channel-open probability and the activation of the channel by anaesthetics. Structures of TASK-1 bound to two high-affinity inhibitors show that both compounds bind below the selectivity filter and are trapped in the vestibule by the X-gate, which explains their exceptionally low washout rates. The presence of the X-gate in TASK channels explains many aspects of their physiological and pharmacological behaviour, which will be beneficial for the future development and optimization of TASK modulators for the treatment of heart, lung and sleep disorders.


The X-ray crystal structure of the potassium channel TASK-1 reveals the presence of an X-gate, which traps small-molecule inhibitors in the intramembrane vestibule and explains their low washout rates from the channel.


  
Importance and vulnerability of the world's water towers 期刊论文
NATURE, 2020, 577 (7790) : 364-+
作者:  Krebs, John R.;  Hassell, Michael
收藏  |  浏览/下载:65/0  |  提交时间:2020/04/16

Mountains are the water towers of the world, supplying a substantial part of both natural and anthropogenic water demands(1,2). They are highly sensitive and prone to climate change(3,4), yet their importance and vulnerability have not been quantified at the global scale. Here we present a global water tower index (WTI), which ranks all water towers in terms of their water-supplying role and the downstream dependence of ecosystems and society. For each water tower, we assess its vulnerability related to water stress, governance, hydropolitical tension and future climatic and socioeconomic changes. We conclude that the most important (highest WTI) water towers are also among the most vulnerable, and that climatic and socio-economic changes will affect them profoundly. This could negatively impact 1.9 billion people living in (0.3 billion) or directly downstream of (1.6 billion) mountainous areas. Immediate action is required to safeguard the future of the world'  s most important and vulnerable water towers.