title: Interaction of the Human Papillomavirus E6 Oncoprotein with Sorting Nexin 27 Modulates Endocytic Cargo Transport Pathways.
abstract: A subset of high-risk Human Papillomaviruses (HPVs) are the causative agents of a large number of human cancers, of which cervical is the most common. Two viral oncoproteins, E6 and E7, contribute directly towards the development and maintenance of malignancy. A characteristic feature of the E6 oncoproteins from cancer-causing HPV types is the presence of a PDZ binding motif (PBM) at its C-terminus, which confers interaction with cellular proteins harbouring PDZ domains. Here we show that this motif allows E6 interaction with Sorting Nexin 27 (SNX27), an essential component of endosomal recycling pathways. This interaction is highly conserved across E6 proteins from multiple high-risk HPV types and is mediated by a classical PBM-PDZ interaction but unlike many E6 targets, SNX27 is not targeted for degradation by E6. Rather, in HPV-18 positive cell lines the association of SNX27 with components of the retromer complex and the endocytic transport machinery is altered in an E6 PBM-dependent manner. Analysis of a SNX27 cargo, the glucose transporter GLUT1, reveals an E6-dependent maintenance of GLUT1 expression and alteration in its association with components of the endocytic transport machinery. Furthermore, knockdown of E6 in HPV-18 positive cervical cancer cells phenocopies the loss of SNX27, both in terms of GLUT1 expression levels and its vesicular localization, with a concomitant marked reduction in glucose uptake, whilst loss of SNX27 results in slower cell proliferation in low nutrient conditions. These results demonstrate that E6 interaction with SNX27 can alter the recycling of cargo molecules, one consequence of which is modulation of nutrient availability in HPV transformed tumour cells.
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Padriciano, Trieste, Italy.
authors.forename: Ketaki
authors.initials: K
authors.lastname: Ganti
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Padriciano, Trieste, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Massimi
authors.affiliation: CONACyT Research Fellow, Instituto Nacional de Cancerologia, Mexico/Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico. Col. Seccion XVI, Tlalpan, Mexico.
authors.forename: Joaquin
authors.initials: J
authors.lastname: Manzo-Merino
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Padriciano, Trieste, Italy.|Division of Molecular Medicine, Ruđjer Bošković Institute, Zagreb, Croatia.
authors.forename: Vjekoslav
authors.initials: V
authors.lastname: Tomaić
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Padriciano, Trieste, Italy.
authors.forename: David
authors.initials: D
authors.lastname: Pim
authors.affiliation: National Heart, Blood and Lung Institute, NIH, Bethesda, Maryland, United States of America.
authors.forename: Martin P
authors.initials: MP
authors.lastname: Playford
authors.affiliation: Instituto Nacional de Cancerologia, Mexico/Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico. Col. Seccion XVI, Tlalpan, Mexico.
authors.forename: Marcela
authors.initials: M
authors.lastname: Lizano
authors.affiliation: Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom.
authors.forename: Sally
authors.initials: S
authors.lastname: Roberts
authors.affiliation: Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, United Kingdom.
authors.forename: Christian
authors.initials: C
authors.lastname: Kranjec
authors.affiliation: Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Doorbar
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Padriciano, Trieste, Italy.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Banks
mesh_terms: D000595:Amino Acid Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D005260:Female; D006367:HeLa Cells; D052161:Human papillomavirus 18 / Q000502:physiology*; D006801:Humans; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism*; D054731:PDZ Domains; D010766:Phosphorylation; D011485:Protein Binding; D021381:Protein Transport; D058305:Sorting Nexins / Q000235:genetics / Q000378:metabolism*; D002583:Uterine Cervical Neoplasms / Q000821:virology*
chemical_list: D004268:DNA-Binding Proteins; C052603:E6 protein, Human papillomavirus type 18; D009856:Oncogene Proteins, Viral; C522885:SNX27 protein, human; D058305:Sorting Nexins