Cryo-EM structures of human TRPC5 reveal interaction of a xanthine-based TRPC1/4/5 inhibitor with a conserved lipid binding site
Cryo-EM structures of human TRPC5 reveal interaction of a xanthine-based TRPC1/4/5 inhibitor with a conserved lipid binding site
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DOI：
10.1101/2020.04.17.047456
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发表时间：
2020-04
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影响因子：
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通讯作者：
D. J. Wright;K. Simmons;Rachel M. Johnson;D. Beech;S. Muench;R. Bon
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作者：
D. J. Wright;K. Simmons;Rachel M. Johnson;D. Beech;S. Muench;R. Bon
TRPC 1/4/5通道是一种与多种疾病有关的非特异性阳离子通道，TRPC 1/4/5抑制剂最近已进入首批临床试验。然而，基础和翻译研究需要更好地了解TRPC 1/4/5通道的调节内源性和外源性因素。尽管已经报道了几种有效的和选择性的TRPC 1/4/5调节剂，但对其作用模式的机理认识的缺乏仍然是开发新的化学探针和候选药物的障碍。黄嘌呤类调节剂包括迄今为止描述的最有效和选择性的TRPC 1/4/5抑制剂，以及TRPC 5激活剂。我们以前的研究表明，黄嘌呤相互作用，到目前为止，难以捉摸的口袋TRPC 1/4/5通道，是必不可少的通道门控。靶向这个口袋可能是TRPC 1/4/5药物发现的一个有前途的策略。在这里，我们报告的第一个结构的小分子结合的TRPC 145通道-人TRPC 5与黄嘌呤Pico 145-至3.0 kDa的复合物。我们发现Pico 145结合TRPC 5的保守脂质结合位点，在那里它取代了结合的磷脂。我们的研究结果解释了基于黄嘌呤的TRPC 1/4/5调节剂的作用模式，并提出了内源性因素如（磷酸）脂质和Zn 2+离子对TRPC 1/4/5调节的结构基础。这些研究为基于结构设计新一代TRPC 1/4/5调节剂奠定了基础。
TRPC1/4/5 channels are non-specific cation channels implicated in a wide variety of diseases, and TRPC1/4/5 inhibitors have recently entered the first clinical trials. However, fundamental and translational studies require a better understanding of TRPC1/4/5 channel regulation by endogenous and exogenous factors. Although several potent and selective TRPC1/4/5 modulators have been reported, the paucity of mechanistic insights into their modes-of-action remains a barrier to the development of new chemical probes and drug candidates. The xanthine class of modulators includes the most potent and selective TRPC1/4/5 inhibitors described to date, as well as TRPC5 activators. Our previous studies suggest that xanthines interact with a, so far, elusive pocket of TRPC1/4/5 channels that is essential to channel gating. Targeting this pocket may be a promising strategy for TRPC1/4/5 drug discovery. Here we report the first structure of a small molecule-bound TRPC1/4/5 channel – human TRPC5 in complex with the xanthine Pico145 – to 3.0 Å. We found that Pico145 binds to a conserved lipid binding site of TRPC5, where it displaces a bound phospholipid. Our findings explain the mode-of-action of xanthine-based TRPC1/4/5 modulators, and suggest a structural basis for TRPC1/4/5 modulation by endogenous factors such as (phospho)lipids and Zn2+ ions. These studies lay the foundations for the structure-based design of new generations of TRPC1/4/5 modulators.