title: The C-terminal region of the non-structural protein 2B from Hepatitis A Virus demonstrates lipid-specific viroporin-like activity.
abstract: Viroporins are virally encoded, membrane-active proteins, which enhance viral replication and assist in egress of viruses from host cells. The 2B proteins in the picornaviridae family are known to have viroporin-like properties, and play critical roles during virus replication. The 2B protein of Hepatitis A Virus (2B), an unusual picornavirus, is somewhat dissimilar from its analogues in several respects. HAV 2B is approximately 2.5 times the length of other 2B proteins, and does not disrupt calcium homeostasis or glycoprotein trafficking. Additionally, its membrane penetrating properties are not yet clearly established. Here we show that the membrane interacting activity of HAV 2B is localized in its C-terminal region, which contains an alpha-helical hairpin motif. We show that this region is capable of forming small pores in membranes and demonstrates lipid specific activity, which partially rationalizes the intracellular localization of full-length 2B. Using a combination of biochemical assays and molecular dynamics simulation studies, we also show that HAV 2B demonstrates a marked propensity to dimerize in a crowded environment, and probably interacts with membranes in a multimeric form, a hallmark of other picornavirus viroporins. In sum, our study clearly establishes HAV 2B as a bona fide viroporin in the picornaviridae family.
authors.affiliation: Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, Hauz Khas, New Delhi -110016, India.
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Shukla
authors.affiliation: Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, Hauz Khas, New Delhi -110016, India.
authors.forename: Debajit
authors.initials: D
authors.lastname: Dey
authors.affiliation: Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, Hauz Khas, New Delhi -110016, India.
authors.forename: Kamalika
authors.initials: K
authors.lastname: Banerjee
authors.affiliation: Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, Hauz Khas, New Delhi -110016, India.
authors.forename: Anshu
authors.initials: A
authors.lastname: Nain
authors.affiliation: Kusuma School of Biological Sciences, Indian Institute of Technology-Delhi, Hauz Khas, New Delhi -110016, India.
authors.forename: Manidipa
authors.initials: M
authors.lastname: Banerjee
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D019281:Dimerization; D000067493:Dynamic Light Scattering; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D030041:Hepatitis A virus / Q000378:metabolism*; D006801:Humans; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D008856:Microscopy, Fluorescence; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D053586:Virus Internalization
chemical_list: C116507:2B protein, hepatitis A virus; D008081:Liposomes; D010455:Peptides; D011993:Recombinant Fusion Proteins; D017361:Viral Nonstructural Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins