Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
27
pubmed:dateCreated
1993-10-20
pubmed:abstractText
The relative levels of phosphatidylinositol-3'-kinase (PI3K) activity were measured in interleukin-2 (IL-2)-dependent helper (HT-2) and cytolytic (CTLL-2) T-cell clones that had been stably transfected with expression plasmids encoding either the normal p56-Lck kinase or a mutant version of this kinase, p56-Lck(Y505F), that has constitutively high levels of kinase activity. Stimulation of untransfected T-cells or of transfected T-cells containing increased levels of normal p56-Lck resulted in an approximate doubling of the relative amounts of total cellular PI3K activity. In contrast, T-cells producing the activated version of p56-Lck contained levels of PI3K activity comparable to or slightly higher than those found IL-2-stimulated control cells, even in the absence of IL-2. Assessments of the relative levels of PI3K activity in immunoprecipitates prepared with the use of anti-phosphotyrosine-specific antibodies revealed constitutively high levels of anti-phosphotyrosine-immunoprecipitable PI3K activity in T-cells containing p56-Lck(Y505F), as opposed to T-cells containing normal p56-Lck where increases in anti-PY-immunoprecipitable PI3K activity were IL-2-inducible. IL-2 stimulation of T-cells containing the normal p56-Lck kinase resulted in marked increases in the relative amounts of PI3K activity and p85 that were coimmunoprecipitated when using anti-p56-Lck antibodies. In contrast, PI3K activity and the p85 subunit of PI3K could be coimmunoprecipitated from T-cells producing the activated p56-Lck(Y505F) kinase even in the absence of IL-2 stimulation, implying constitutive association of PI3K with the activated Lck kinase. Taken together with previous studies showing that IL-2 induces rapid increases in the activities of both p56-Lck and PI3K in T-cells, these findings suggest that p56-Lck lies immediately upstream of PI3K in a signal transduction cascade initiated by the binding of IL-2 to its specific receptor on T-lymphocytes.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
268
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
20031-6
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:8397196-Amino Acid Sequence, pubmed-meshheading:8397196-Animals, pubmed-meshheading:8397196-Antibodies, pubmed-meshheading:8397196-Cells, Cultured, pubmed-meshheading:8397196-Immunoblotting, pubmed-meshheading:8397196-Interleukin-2, pubmed-meshheading:8397196-Lymphocyte Specific Protein Tyrosine Kinase p56(lck), pubmed-meshheading:8397196-Mice, pubmed-meshheading:8397196-Molecular Sequence Data, pubmed-meshheading:8397196-Peptides, pubmed-meshheading:8397196-Phosphatidylinositol 3-Kinases, pubmed-meshheading:8397196-Phosphotransferases, pubmed-meshheading:8397196-Protein-Tyrosine Kinases, pubmed-meshheading:8397196-Recombinant Proteins, pubmed-meshheading:8397196-T-Lymphocytes, Cytotoxic, pubmed-meshheading:8397196-T-Lymphocytes, Helper-Inducer, pubmed-meshheading:8397196-Transfection
pubmed:year
1993
pubmed:articleTitle
Evidence that protein tyrosine kinase p56-Lck regulates the activity of phosphatidylinositol-3'-kinase in interleukin-2-dependent T-cells.
pubmed:affiliation
Department of Pathology & Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't