Linked Life Data

18579178

Source:http://linkedlifedata.com/resource/pubmed/id/18579178

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2008-7-29
pubmed:abstractText
Previously, we showed that the Vpu protein from HIV-1 subtype C is more efficiently transported to the cell surface than the well studied subtype B Vpu (Pacyniak et al., 2005) and that a SHIV expressing the subtype C Vpu exhibited a decreased rate of CD4+ T cell loss following inoculation in macaques (Hill et al., 2008). In this study, we examined the role of overlapping tyrosine-based (YXXPhi) and dileucine-based ([D/E]XXXL[L/I]) motifs in the membrane proximal region of the subtype C Vpu (EYRKLL) in Vpu intracellular transport, CD4 surface expression and virus release from the cell surface. We constructed three site-directed mutants of the subtype C vpu and fused these genes to the gene for enhanced green fluorescent protein (EGFP). The first mutation made altered the tyrosine (EARKLL; VpuSCEGFPY35A), the second altered the dileucine motif (EYRKLG; VpuSCEGFPL39G), and the third contained both amino acid substitutions (EARKLG; VpuSCEGFPYL35,39AG) in this region of the Vpu protein. The VpuSCEGFPY35A protein was transported to the cell surface similar to the unmodified VpuSCEGFP1 while VpuSCEGFPL39G was expressed at the cell surface at significantly reduced levels. The VpuSCEGFPYL35,39AG was found to have an intermediate level of cell surface expression. All three mutant Vpu proteins were analyzed for the ability to prevent cell surface expression of CD4. We found that both single mutants did not significantly effect CD4 surface expression while the double mutant (VpuSCEGFPYL35,39AG) was significantly less efficient at preventing cell surface CD4 expression. Chimeric simian human immunodeficiency viruses were constructed with these mutations in vpu (SHIVSCVpuY35A, SHIVSCVpuL39G and SHIVSCVpuYL35,39AG). Our results indicate that SHIVSCVpuL39G replicated much more efficiently and was much more cytopathic than SHIVSCVpu. In contrast, SHIVSCVpuY35A and SHIVSCVpuYL35,39AG replicated less efficiently when compared to the parental SHIVSCVpu. Taken together, these results show for the first time that the membrane proximal tyrosine-based sorting motif in the cytoplasmic domain of Vpu is essential for efficient virus release. These results also indicate that the dileucine-based sorting motif affects the intracellular trafficking of subtype C Vpu proteins, virus replication, and release.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0042-6822
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
378
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
58-68
pubmed:meshHeading
pubmed-meshheading:18579178-Animals, pubmed-meshheading:18579178-Biological Transport, pubmed-meshheading:18579178-Cell Line, pubmed-meshheading:18579178-Cell Membrane, pubmed-meshheading:18579178-Genes, vpu, pubmed-meshheading:18579178-Green Fluorescent Proteins, pubmed-meshheading:18579178-HIV-1, pubmed-meshheading:18579178-HeLa Cells, pubmed-meshheading:18579178-Human Immunodeficiency Virus Proteins, pubmed-meshheading:18579178-Humans, pubmed-meshheading:18579178-Leucine, pubmed-meshheading:18579178-Protein Sorting Signals, pubmed-meshheading:18579178-Protein Transport, pubmed-meshheading:18579178-Recombinant Fusion Proteins, pubmed-meshheading:18579178-Simian immunodeficiency virus, pubmed-meshheading:18579178-Tyrosine, pubmed-meshheading:18579178-Viral Regulatory and Accessory Proteins
pubmed:year
2008
pubmed:articleTitle
Requirements of the membrane proximal tyrosine and dileucine-based sorting signals for efficient transport of the subtype C Vpu protein to the plasma membrane and in virus release.
pubmed:affiliation
Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Boulevard Kansas City, Kansas 66160, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural