title: A Novel PDZ Domain Interaction Mediates the Binding between Human Papillomavirus 16 L2 and Sorting Nexin 27 and Modulates Virion Trafficking.
abstract: Previous studies have demonstrated an interaction between sorting nexin 17 and the L2 capsid proteins from a variety of papillomavirus types. This interaction is required for late endosomal trafficking of the L2 protein and entry of the L2/DNA complex into the nucleus during infection. Here we show an interaction between papillomavirus L2 proteins and the related PX-FERM family member sorting nexin 27 (SNX27), which is mediated in part by a novel interaction between the PDZ domain of SNX27 and sequences in a central portion of L2. The interaction is direct and, unlike that with SNX17, is variable in strength depending on the papillomavirus type. We show that small interfering RNA (siRNA)-mediated knockdown of SNX27 alone leads to a marginal reduction in the efficiency of viral infection but that double knockdown of both sorting nexins results in a striking reduction in infection, greater than that observed for the knockdown of either sorting nexin alone. These results suggest that the HPV L2 proteins can interact through distinct mechanisms with multiple components of the cellular cargo-sorting machinery.
  
  
  OBJECTIVE
  The trafficking of papillomaviruses to the host cell nucleus during their natural infectious life cycle is an incompletely understood process. Studies have suggested that the virus minor capsid protein L2 can interact with the endosomal recycling pathway, in part by association with sorting nexin 17, to ensure that virus DNA bound to L2 is recycled through the trans-Golgi network rather than back to the plasma membrane. In this study, we characterize the interaction between L2 and a second sorting nexin, SNX27, which is also part of the retromer complex. The study furthers our understanding of papillomavirus infection dynamics and provides potential tools for the further dissection of endosomal structure and function.
authors.affiliation: Department of Tumour Virology, ICGEB, Trieste, Italy pim@icgeb.org.
authors.forename: David
authors.initials: D
authors.lastname: Pim
authors.affiliation: Department of Molecular Virology, Adam Mickiewicz University, Poznan, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Broniarczyk
authors.affiliation: Centre for Biomedical Sciences and Engineering, University of Nova Gorica, Nova Gorica, Slovenia.
authors.forename: Martina
authors.initials: M
authors.lastname: Bergant
authors.affiliation: National Heart, Lung, and Blood Institute, NIH, Bethesda, Maryland, USA.
authors.forename: Martin P
authors.initials: MP
authors.lastname: Playford
authors.affiliation: Department of Tumour Virology, ICGEB, Trieste, Italy.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Banks
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D001692:Biological Transport; D002213:Capsid / Q000737:chemistry / Q000378:metabolism; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism / Q000821:virology; D002467:Cell Nucleus / Q000378:metabolism / Q000821:virology; D004247:DNA / Q000235:genetics / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism / Q000821:virology; D015870:Gene Expression; D057809:HEK293 Cells; D054884:Host-Pathogen Interactions; D052162:Human papillomavirus 16 / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes; D008969:Molecular Sequence Data; D009856:Oncogene Proteins, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054731:PDZ Domains / Q000235:genetics*; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D058305:Sorting Nexins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication / Q000235:genetics
chemical_list: D036022:Capsid Proteins; C063316:L2 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D034741:RNA, Small Interfering; C487895:SNX17 protein, human; C522885:SNX27 protein, human; D058305:Sorting Nexins; D004247:DNA