| Autor: |
R L, Palmer-Crocker, J S, Pober |
| Rok vydání: |
1995 |
| Předmět: |
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| Zdroj: |
Journal of immunology (Baltimore, Md. : 1950). 154(6) |
| ISSN: |
0022-1767 |
| Popis: |
IL-4 triggers tyrosine phosphorylation of a single major substrate (M(r) 145,000) in cultured human endothelial cells (EC) as detected by Western blot of whole cell lysates or of anti-phosphotyrosine immunoprecipitates. Phosphorylation of this substrate depends on IL-4 concentration (appearance at 10 U/ml, maximal at 300 to 1000 U/ml) and time of treatment (onset by 1 min, peak at 5 to30 min, duration of 60 to 120 min). Immunoprecipitation with specific mAb identified the phosphorylated substrate as the IL-4R. Treatment of EC with IL-4 alone causes only a small increase in the expression of vascular cell adhesion molecule-1 (VCAM-1), but IL-4 significantly augments the level of VCAM-1 expression induced by PMA. Pretreatment of EC with herbimycin A (0.5 to 1.0 microgram/ml) for 12 to 18 h abrogates both IL-4-induced tyrosine phosphorylation and IL-4-augmented VCAM-1 expression. This concentration of herbimycin A does not inhibit and may augment PMA-induced VCAM-1 expression in replicate wells. These observations suggest that IL-4 induction of VCAM-1 in EC involves the activation of an as yet unidentified protein tyrosine kinase that phosphorylates the IL-4R. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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