Structure of the bile acid transporter and HBV receptor NTCP.

Chronic infection with hepatitis B virus (HBV) affects more than 290 million people worldwide, is a major cause of cirrhosis and hepatocellular carcinoma, and results in an estimated 820,000 deaths annually1,2. For HBV infection to be established, a molecular interaction is required between the large glycoproteins of the virus envelope (known as LHBs) and the host entry receptor sodium taurocholate co-transporting polypeptide (NTCP), a sodium-dependent bile acid transporter from the blood to hepatocytes3. However, the molecular basis for the virus-transporter interaction is poorly understood. Here we report the cryo-electron microscopy structures of human, bovine and rat NTCPs in the apo state, which reveal the presence of a tunnel across the membrane and a possible transport route for the substrate. Moreover, the cryo-electron microscopy structure of human NTCP in the presence of the myristoylated preS1 domain of LHBs, together with mutation and transport assays, suggest a binding mode in which preS1 and the substrate compete for the extracellular opening of the tunnel in NTCP. Our preS1 domain interaction analysis enables a mechanistic interpretation of naturally occurring HBV-insusceptible mutations in human NTCP. Together, our findings provide a structural framework for HBV recognition and a mechanistic understanding of sodium-dependent bile acid translocation by mammalian NTCPs. © 2022. The Author(s), under exclusive licence to Springer Nature Limited.

Citation

Jinta Asami, Kanako Terakado Kimura, Yoko Fujita-Fujiharu, Hanako Ishida, Zhikuan Zhang, Yayoi Nomura, Kehong Liu, Tomoko Uemura, Yumi Sato, Masatsugu Ono, Masaki Yamamoto, Takeshi Noda, Hideki Shigematsu, David Drew, So Iwata, Toshiyuki Shimizu, Norimichi Nomura, Umeharu Ohto. Structure of the bile acid transporter and HBV receptor NTCP. Nature. 2022 Jun;606(7916):1021-1026

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PMID: 35580629

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