1,265
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Sodium taurocholate cotransporting polypeptide is a functional receptor for human hepatitis B and D virus

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Human hepatitis B virus (HBV) infection and HBV-related diseases remain a major public health problem. Individuals coinfected with its satellite hepatitis D virus (HDV) have more severe disease. Cellular entry of both viruses is mediated by HBV envelope proteins. The pre-S1 domain of the large envelope protein is a key determinant for receptor(s) binding. However, the identity of the receptor(s) is unknown. Here, by using near zero distance photo-cross-linking and tandem affinity purification, we revealed that the receptor-binding region of pre-S1 specifically interacts with sodium taurocholate cotransporting polypeptide (NTCP), a multiple transmembrane transporter predominantly expressed in the liver. Silencing NTCP inhibited HBV and HDV infection, while exogenous NTCP expression rendered nonsusceptible hepatocarcinoma cells susceptible to these viral infections. Moreover, replacing amino acids 157–165 of nonfunctional monkey NTCP with the human counterpart conferred its ability in supporting both viral infections. Our results demonstrate that NTCP is a functional receptor for HBV and HDV.

          DOI: http://dx.doi.org/10.7554/eLife.00049.001

          eLife digest

          Liver diseases related to the human hepatitis B virus (HBV) kill about 1 million people every year, and more than 350 million people around the world are infected with the virus. Some 15 million of these people are also infected with the hepatitis D virus (HDV), which is a satellite virus of HBV, and this places them at an even higher risk of liver diseases, including cancer. The viruses are known to enter liver cells by binding to receptors on their surface before being engulfed.

          Both HBV and HDV have outer coats that consist of three kinds of envelope proteins, and a region called the pre-S1 domain in one of them is known to have a central role in the interaction between the viruses and the receptors and, therefore, in infecting the cells. However, the identity of the HBV receptor has remained a mystery. Now Yan et al. have identified this receptor to be sodium taurocholate cotransporting polypeptide. This protein, known as NTCP for short, is normally involved in the circulation of bile acids in the body.

          In addition to humans, only two species are known to be susceptible to infection by human HBV and HDV—chimpanzees and a small mammal known as the treeshrew. Yan et al. started by isolating primary liver cells from treeshrews, and then used a combination of advanced purification and mass spectrometry analysis to show that the NTCP on the surface of the cells interacts with the pre-S1 domain in HBV.

          The authors then performed a series of gene knockdown experiments on liver cells of both human and treeshrew origin: when the gene that codes for NTCP was silenced, HBV infection was greatly reduced. Moreover, they were able to transfect HepG2 cells—which are widely used in research into liver disease, but are not susceptible to HBV and HDV infection—with NTCP from humans and treeshrews to make them susceptible. Similarly, although monkeys are not susceptible to HBV, replacing just five amino acids in monkey NTCP with their human counterparts was enough to make the monkey NTCP a functional receptor for the viruses.

          In the past, basic research into HBV and the development of antiviral therapeutics have both been hindered by the lack of suitable in vitro infection systems and animal models. Now, the work of Yan et al. means that it will be possible to use NTCP-complemented HepG2 cells for challenges as diverse as fundamental studies of basic viral entry/replication mechanisms and large-scale drug screening. It is also possible that HBV and HDV infection might interfere with some of the important physiological functions carried out by NTCP, so the latest work could also be of interest to medical scientists working on other diseases related to these infections.

          DOI: http://dx.doi.org/10.7554/eLife.00049.002

          Related collections

          Most cited references44

          • Record: found
          • Abstract: found
          • Article: not found

          The PANTHER database of protein families, subfamilies, functions and pathways

          PANTHER is a large collection of protein families that have been subdivided into functionally related subfamilies, using human expertise. These subfamilies model the divergence of specific functions within protein families, allowing more accurate association with function (ontology terms and pathways), as well as inference of amino acids important for functional specificity. Hidden Markov models (HMMs) are built for each family and subfamily for classifying additional protein sequences. The latest version, 5.0, contains 6683 protein families, divided into 31 705 subfamilies, covering ∼90% of mammalian protein-coding genes. PANTHER 5.0 includes a number of significant improvements over previous versions, most notably (i) representation of pathways (primarily signaling pathways) and association with subfamilies and individual protein sequences; (ii) an improved methodology for defining the PANTHER families and subfamilies, and for building the HMMs; (iii) resources for scoring sequences against PANTHER HMMs both over the web and locally; and (iv) a number of new web resources to facilitate analysis of large gene lists, including data generated from high-throughput expression experiments. Efforts are underway to add PANTHER to the InterPro suite of databases, and to make PANTHER consistent with the PIRSF database. PANTHER is now publicly available without restriction at http://panther.appliedbiosystems.com.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            DTASelect and Contrast: tools for assembling and comparing protein identifications from shotgun proteomics.

            The components of complex peptide mixtures can be separated by liquid chromatography, fragmented by tandem mass spectrometry, and identified by the SEQUEST algorithm. Inferring a mixture's source proteins requires that the identified peptides be reassociated. This process becomes more challenging as the number of peptides increases. DTASelect, a new software package, assembles SEQUEST identifications and highlights the most significant matches. The accompanying Contrast tool compares DTASelect results from multiple experiments. The two programs improve the speed and precision of proteomic data analysis.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Hepatitis B virus infection initiates with a large surface protein-dependent binding to heparan sulfate proteoglycans.

              Contrary to many other viruses, the initial steps of the hepatitis B virus (HBV) infection, including attachment to hepatocytes, specific receptor interactions, and membrane fusion, are unsolved. Using HepaRG cells as an in vitro cell culture system, we here report that HBV entry into hepatocytes depends on the interaction with the glycosaminoglycan (GAG) side chains of cell-surface-associated heparan sulfate proteoglycans. Binding to GAGs requires the integrity of the pre-S domain as a part of the large (L-) viral envelope protein. HBV infection was abrogated by incubation of virions with heparin, but not the structurally related GAGs chondroitin sulfate A, B, and C. Infection was also abolished by suramin, a known inhibitor of duck hepatitis B virus infection or highly sulfated dextran sulfate. Polycationic substances such as poly-L-lysine, polybrene, and protamine also prevented infection, however, by addressing cellular components. Enzymatic removal of defined acidic carbohydrate structures from the cell surface using heparinase I/III or the obstruction of GAG synthesis by sodium chlorate inhibited HBV infection of HepaRG cells and, moreover, led to a reduction of HBV cell surface binding sites. The biochemical analysis showed selective binding of L-protein-enriched viral particles (virions or filaments) to heparin. GAG-dependent binding of HBV was improved by polyethylene glycol, a substance that specifically enhances HBV infection. HBV infection requires the initial attachment to the carbohydrate side chains of hepatocyte-associated heparan sulfate proteoglycans as attachment receptors. This interaction initializes the multistep entry process of HBV and cannot be bypassed by alternative routes.
                Bookmark

                Author and article information

                Contributors
                Role: Reviewing editor
                Journal
                eLife
                Elife
                elife
                eLife
                eLife
                eLife Sciences Publications, Ltd
                2050-084X
                13 November 2012
                2012
                : 1
                : e00049
                Affiliations
                [1 ]Graduate program in School of Life Sciences, Peking University , Beijing, China
                [2 ]National Institute of Biological Sciences , Beijing, China
                [3 ]Graduate program in Chinese Academy of Medical Sciences and Peking Union Medical College , Beijing, China
                UT Southwestern Medical School , United States
                UT Southwestern Medical School , United States
                Author notes
                [* ]For correspondence: liwenhui@ 123456nibs.ac.cn
                [†]

                These authors contributed equally to this work.

                Article
                00049
                10.7554/eLife.00049
                3485615
                23150796
                fb793cdf-c0c2-41cb-b993-5acf20a5a4f6
                Copyright © 2012, Yan et al

                This article is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use and redistribution provided that the original author and source are credited.

                History
                : 11 July 2012
                : 05 September 2012
                Funding
                Funded by: The Ministry of Science and Technology of the People's Republic of China
                Award ID: 2010CB530101
                Award Recipient :
                Funded by: Science and Technology Bureau of Beijing Municipal Government
                Award Recipient :
                Funded by: The Ministry of Science and Technology of the People's Republic of China
                Award ID: 2011CB812501
                Award Recipient :
                The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
                Categories
                Research Article
                Biochemistry
                Microbiology and Infectious Disease
                Custom metadata
                0.1
                Biochemical and genetic tests have revealed that a liver protein called NTCP is a functional receptor for hepatitis B and D viruses, which should lead to an improved understanding of the infections caused by these viruses and assist the development of new intervention strategies.

                Life sciences
                sodium taurocholate cotransporting polypeptide,receptor,hepatitis b virus,hepatitis d virus,liver,virus infection,viruses,other

                Comments

                Comment on this article