Linked Life Data

8626571

Source:http://linkedlifedata.com/resource/pubmed/id/8626571

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
17
pubmed:dateCreated
1996-6-21
pubmed:abstractText
Vif is a 23-kDa protein encoded by human immunodeficiency virus, type 1 (HIV-1) which is important for virion infectivity. Here, we describe the phosphorylation of HIV-1 Vif and its role in HIV-1 replication. In vivo studies demonstrated that Vif is highly phosphorylated on serine and threonine residues. To identify phosphorylation sites and characterize the Vif kinase(s), Vif was expressed in Escherichia coli and purified for use as a substrate in in vitro kinase assays. The purified Vif protein was phosphorylated in vitro on serine and threonine residues by a kinase(s) present in both cytosol and membrane fractions. Phosphorylation of Vif was stimulated by phorbol 12-myristate 13-acetate and inhibited by staurosporine and hypericin, a drug with potent anti-HIV activity. The Vif kinase(s) was resistant to inhibitors of protein kinase C, cAMP-dependent kinase, and cGMP-dependent kinase, suggesting that it is distinct from these enzymes. To identify the phosphorylation sites, 32P-labeled Vif was digested by V8 protease and the peptides were resolved by reverse-phase high performance liquid chromatography. Radioactive peptide sequencing identified three phosphorylation sites within the C terminus, Ser144, Thr155, and Thr188. Two-dimensional tryptic phosphopeptide mapping indicated that these sites are also phosphorylated in vivo. Both Ser144 and Thr188 are contained in the recognition motifs (R/KXXS*/T* and R/KXXXS*/T*) used by serine/threonine protein kinases such as cGMP-dependent kinase and PKC. Ser144 is present in the motif SLQXLA, which is the most highly conserved sequence among all lentivirus Vif proteins. Mutation of Ser144 to alanine resulted in loss of Vif activity and >90% inhibition of HIV-1 replication. These studies suggest that phosphorylation of Vif by a serine/threonine protein kinase(s) plays an important role in regulating HIV-1 replication and infectivity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
271
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10121-9
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:8626571-Alkaloids, pubmed-meshheading:8626571-Amino Acid Sequence, pubmed-meshheading:8626571-Base Sequence, pubmed-meshheading:8626571-Cells, Cultured, pubmed-meshheading:8626571-DNA Primers, pubmed-meshheading:8626571-Enzyme Inhibitors, pubmed-meshheading:8626571-Gene Products, vif, pubmed-meshheading:8626571-Genetic Complementation Test, pubmed-meshheading:8626571-HIV-1, pubmed-meshheading:8626571-Humans, pubmed-meshheading:8626571-Molecular Sequence Data, pubmed-meshheading:8626571-Peptide Mapping, pubmed-meshheading:8626571-Phosphorylation, pubmed-meshheading:8626571-Phosphoserine, pubmed-meshheading:8626571-Phosphothreonine, pubmed-meshheading:8626571-Point Mutation, pubmed-meshheading:8626571-Protein Kinase Inhibitors, pubmed-meshheading:8626571-Recombinant Proteins, pubmed-meshheading:8626571-Staurosporine, pubmed-meshheading:8626571-Structure-Activity Relationship, pubmed-meshheading:8626571-Virus Replication, pubmed-meshheading:8626571-vif Gene Products, Human Immunodeficiency Virus
pubmed:year
1996
pubmed:articleTitle
Phosphorylation of Vif and its role in HIV-1 replication.
pubmed:affiliation
Division of Human Retrovirology, Dana-Farber Cancer Institute and the Departments of Pathology and Neurology, Harvard Medical School, Boston, Massachusetts 02115, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't