title: HIV-2 viral protein X (Vpx) ubiquitination is dispensable for ubiquitin ligase interaction and effects on macrophage infection.
abstract: HIV-2 Vpx, a virus-associated accessory protein, is critical for infection of non-dividing myeloid cells. To understand the function of Vpx ubiquitination, interaction with an E3 ubiquitin ligase complex, and ability to overcome an inhibition of reverse transcription, we analyzed Vpx lysine mutants for their function and replication capability in macrophages. Both Wt Vpx and Vpx TA (lysine-less Vpx) localized to the cytoplasm and nucleus in HeLa cells. All HIV-2 Vpx lysine mutants were functional in virion packaging. However, ubiquitination was absent with Vpx TA and Vpx K84A mutants, indicating a lack of ubiquitin on positions K68 and K77. Mutants Vpx K68A and K77A were unable to infect macrophages due to impaired reverse transcription from loss of interaction with the ubiquitin substrate receptor, DCAF1. Even though Vpx K84A lacked ubiquitination, it bound DCAF1, and infected macrophages comparable to Wt Vpx.
authors.affiliation: Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: McCulley
authors.forename: Lee
authors.initials: L
authors.lastname: Ratner
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D002352:Carrier Proteins / Q000378:metabolism*; D057809:HEK293 Cells; D015658:HIV Infections / Q000821:virology*; D015498:HIV-2 / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008239:Lysine / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism / Q000821:virology*; D008969:Molecular Sequence Data; D017346:Protein Serine-Threonine Kinases; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases; D054875:Ubiquitination; D054334:Viral Regulatory and Accessory Proteins / Q000235:genetics / Q000378:metabolism*; D014771:Virion / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication
chemical_list: D002352:Carrier Proteins; C074286:VPX protein, Human immunodeficiency virus 2; D054334:Viral Regulatory and Accessory Proteins; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases; C530533:DCAF1 protein, human; D017346:Protein Serine-Threonine Kinases; D008239:Lysine