Mechanism of substrate transport and inhibition of the human LAT1-4F2hc amino acid transporter.
Mechanism of substrate transport and inhibition of the human LAT1-4F2hc amino acid transporter.
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DOI：
10.1038/s41421-021-00247-4
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发表时间：
2021-03-23
期刊：
影响因子：
33.5
通讯作者：
Zhou Q
中科院分区：
文献类型：
--
作者：
Yan R;Li Y;Müller J;Zhang Y;Singer S;Xia L;Zhong X;Gertsch J;Altmann KH;Zhou Q
LAT 1（SLC 7A 5）是异聚氨基酸转运蛋白的代表性轻链蛋白之一，与其重链伴侣4F 2 hc（SLC 3A 2）形成异二聚体。LAT 1在许多类型的肿瘤中过表达，并介导药物和激素穿过血脑屏障的转移。因此，LAT 1被认为是癌症治疗的药物靶标，并且可以用于将药物递送到大脑中。在这里，我们合成了三种有效的人LAT 1抑制剂，它们抑制亮氨酸的转运，IC 50值在100和250 nM之间，并解决了相应的LAT 1 - 4F 2 hc复合物的冷冻-EM结构，这些抑制剂的结合分辨率高达2.7或2.8 μ m。该蛋白质呈现向外封闭的构象，抑制剂结合在经典的底物结合口袋中，但其尾部楔入底物结合位点和LAT 1的TM 10之间。我们还以3.4 μ m的总分辨率解析了LAT 1 - 4F 2 hc与3，5-二碘-1-酪氨酸（Diiodo-Tyr）的复合物结构，这揭示了不同的抑制机制，并且可能代表上述面向外的封闭状态和向外开放状态之间的中间构象。据我们所知，这是第一次，面向外的构象是揭示的HAT家庭。我们的研究结果揭示了更重要的见解HAT的工作机制，并为未来的药物设计提供了结构基础。
LAT1 (SLC7A5) is one of the representative light chain proteins of heteromeric amino acid transporters, forming a heterodimer with its heavy chain partner 4F2hc (SLC3A2). LAT1 is overexpressed in many types of tumors and mediates the transfer of drugs and hormones across the blood-brain barrier. Thus, LAT1 is considered as a drug target for cancer treatment and may be exploited for drug delivery into the brain. Here, we synthesized three potent inhibitors of human LAT1, which inhibit transport of leucine with IC50 values between 100 and 250 nM, and solved the cryo-EM structures of the corresponding LAT1-4F2hc complexes with these inhibitors bound at resolution of up to 2.7 or 2.8 Å. The protein assumes an outward-facing occluded conformation, with the inhibitors bound in the classical substrate binding pocket, but with their tails wedged between the substrate binding site and TM10 of LAT1. We also solved the complex structure of LAT1-4F2hc with 3,5-diiodo-l-tyrosine (Diiodo-Tyr) at 3.4 Å overall resolution, which revealed a different inhibition mechanism and might represent an intermediate conformation between the outward-facing occluded state mentioned above and the outward-open state. To our knowledge, this is the first time that the outward-facing conformation is revealed for the HAT family. Our results unveil more important insights into the working mechanisms of HATs and provide a structural basis for future drug design.
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DOI：
10.1073/pnas.96.21.12079
发表时间：
1999-10-12
影响因子：
11.1
作者：
Boado, RJ;Li, JY;Pardridge, WM
通讯作者：
Pardridge, WM
影响因子：
64.8
作者：
Mastroberardino, L;Spindler, B;Verrey, F
通讯作者：
Verrey, F
影响因子：
5.7
作者：
Oda, Koji;Hosoda, Noriko;Endou, Hitoshi
通讯作者：
Endou, Hitoshi
影响因子：
5.6
作者：
Ilgu, Huseyin;Jeckelmann, Jean-Marc;Fotiadis, Dimitrios
通讯作者：
Fotiadis, Dimitrios
影响因子：
6.8
作者：
Kazmier, Kelli;Claxton, Derek P.;Mchaourab, Hassane S.
通讯作者：
Mchaourab, Hassane S.