Tyrosine phosphorylation of a low molecular weight protein induced by RANTES in T-lymphocytes.
The beta-chemokine RANTES, a T-lymphocyte activator, chemoattractant, and inducer of homotypic aggregation, is considered to exert extensive effects on T lymphocytes through either G protein-coupled or protein tyrosine kinase (PTK) signaling pathway. In the present study, we analyzed RANTES-induced signal transduction through PTK as an early event in T-lymphocyte activation. Tyrosine phosphorylation is detected by immunoblots in the human T-cell line H9 after incubation with human recombinant RANTES. The tyrosine phosphorylation of a protein with a molecular mass of about 25 kD is measurable as early as 30 s and maximal at 1-5 min; and is a dose-dependent effect. The phosphorylation response can be abrogated by the tyrosine-kinase inhibitor herbimycin A (HA) but is insensitive to heterotrimeric Galphai protein inhibitor pertussis toxin (Ptx). This phenomenon is also observed in a visible homotypic aggregation response after incubation serum-starved H9 cells with RANTES. The phosphorylation response can not be down-regulated by preincubation with either anti-CC chemokine receptor 5 (CCR5) antibody or HIV-1Bal supernatants. Our results suggest that tyrosine phosphorylation of a protein with molecular mass of about 25 kD via Src-family PTK(s) is an early event in T-lymphocyte activation associated with the homotypic aggregation in response to RANTES.
Zhu
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Institute for Hygiene, University of Innsbruck, Austria.
Speth
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Dierich
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D016227:Benzoquinones; D017252:CD3 Complex / Q000378:metabolism*; D002460:Cell Line; D018946:Chemokine CCL5 / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015497:HIV-1 / Q000276:immunology; D006801:Humans; D047029:Lactams, Macrocyclic; D008213:Lymphocyte Activation; D008970:Molecular Weight; D009500:Neutralization Tests; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011809:Quinones / Q000494:pharmacology; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D019713:Receptors, CCR5 / Q000378:metabolism; D017828:Rifabutin / Q000031:analogs & derivatives; D015398:Signal Transduction / Q000187:drug effects; D013601:T-Lymphocytes / Q000187:drug effects*; D013997:Time Factors; D014443:Tyrosine / Q000378:metabolism*
D016227:Benzoquinones; D017252:CD3 Complex; D018946:Chemokine CCL5; D004791:Enzyme Inhibitors; D047029:Lactams, Macrocyclic; D011809:Quinones; D011948:Receptors, Antigen, T-Cell; D019713:Receptors, CCR5; D017828:Rifabutin; D014443:Tyrosine; C020754:herbimycin; D011505:Protein-Tyrosine Kinases