title: Hepatitis C virus NS5A protein blocks epidermal growth factor receptor degradation via a proline motif- dependent interaction.
abstract: Hepatitis C virus (HCV) establishes a persistent infection that in many cases leads to cirrhosis and hepatocellular carcinoma. The non-structural 5A protein (NS5A) has been implicated in this process as it contains a C-terminal polyproline motif (termed P2) that binds to Src homology 3 (SH3) domains to regulate cellular signalling and trafficking pathways. We have shown previously that NS5A impaired epidermal growth factor (EGF) receptor (EGFR) endocytosis, thereby inhibiting EGF-stimulated EGFR degradation by a mechanism that remained unclear. As EGFR has been implicated in HCV cell entry and trafficking of the receptor involves several SH3-domain containing proteins, we investigated in more detail the mechanisms by which NS5A perturbs EGFR trafficking. We demonstrated that the P2 motif was required for the NS5A-mediated disruption to EGFR trafficking. We further demonstrated that the P2 motif was required for an interaction between NS5A and CMS, a homologue of CIN85 that has previously been implicated in EGFR endocytosis. We provided evidence that CMS was involved in the NS5A-mediated perturbation of EGFR trafficking. We also showed that NS5A effected a loss of EGFR ubiquitination in a P2-motif-dependent fashion. These data provide clues to the mechanism by which NS5A regulates the trafficking of a key cellular receptor and demonstrate for the first time the ability of NS5A to regulate host cell ubiquitination pathways.
authors: School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
authors: Zsofia
authors: Z
authors: Igloi
authors: Department of Virology, Haartman Institute, University of Helsinki and Helsinki University Central Hospital, Helsinki 00014, Finland.
authors: Arunas
authors: A
authors: Kazlauskas
authors: Department of Virology, Haartman Institute, University of Helsinki and Helsinki University Central Hospital, Helsinki 00014, Finland.
authors: Kalle
authors: K
authors: Saksela
authors: School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
authors: Andrew
authors: A
authors: Macdonald
authors: School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
authors: Jamel
authors: J
authors: Mankouri
authors: School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
authors: Mark
authors: M
authors: Harris
mesh_terms: D020816:Amino Acid Motifs; D004705:Endocytosis; D066246:ErbB Receptors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016174:Hepacivirus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006526:Hepatitis C / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology / Q000821:virology; D006801:Humans; D011392:Proline / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D059748:Proteolysis; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase
chemical_list: D066246:ErbB Receptors; D011392:Proline; D017361:Viral Nonstructural Proteins; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase