title: Severe acute respiratory syndrome coronavirus Orf3a protein interacts with caveolin.
abstract: The orf3a (also called X1 or U274) gene is the largest unique open reading frame in the severe acute respiratory syndrome coronavirus genome and has been proposed to encode a protein with three transmembrane domains and a large cytoplasmic domain. Recent work has suggested that the 3a protein may play a structural role in the viral life cycle, although the mechanisms for this remain uncharacterized. Here, the expression of the 3a protein in various in vitro systems is shown, it has been localized to the Golgi region and its membrane topology in transfected cells has been confirmed. Three potential caveolin-1-binding sites were reported to be present in the 3a protein. By using various biochemical, biophysical and genetic techniques, interaction of the 3a protein with caveolin-1 is demonstrated. Any one of the potential sites in the 3a protein was sufficient for this interaction. These results are discussed with respect to the possible roles of the 3a protein in the viral life cycle.
authors.affiliation: Virology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors.forename: Kartika
authors.initials: K
authors.lastname: Padhan
authors.affiliation: Virology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors.forename: Charu
authors.initials: C
authors.lastname: Tanwar
authors.affiliation: Virology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors.forename: Amjad
authors.initials: A
authors.lastname: Hussain
authors.affiliation: Department of Microbiology, Queen Mary Hospital, University of Hong Kong, Hong Kong SAR.
authors.forename: Pui Yan
authors.initials: PY
authors.lastname: Hui
authors.affiliation: Department of Microbiology, Queen Mary Hospital, University of Hong Kong, Hong Kong SAR.
authors.forename: Man Yan
authors.initials: MY
authors.lastname: Lee
authors.affiliation: Department of Microbiology, Queen Mary Hospital, University of Hong Kong, Hong Kong SAR.
authors.forename: Chung Yan
authors.initials: CY
authors.lastname: Cheung
authors.affiliation: Department of Microbiology, Queen Mary Hospital, University of Hong Kong, Hong Kong SAR.
authors.forename: Joseph Sriyal Malik
authors.initials: JSM
authors.lastname: Peiris
authors.affiliation: Virology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors.forename: Shahid
authors.initials: S
authors.lastname: Jameel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D051242:Caveolin 1 / Q000378:metabolism*; D002460:Cell Line; D006224:Cricetinae; D004285:Dogs; D006056:Golgi Apparatus / Q000737:chemistry; D006801:Humans; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D011485:Protein Binding; D025941:Protein Interaction Mapping; D045473:Severe acute respiratory syndrome-related coronavirus / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D015678:Viral Structural Proteins / Q000378:metabolism*; D000086082:Viroporin Proteins
chemical_list: D051242:Caveolin 1; D015678:Viral Structural Proteins; C515313:ORF3A protein, SARS coronavirus; D000086082:Viroporin Proteins