IL-4 induction of VCAM-1 on endothelial cells involves activation of a protein tyrosine kinase.
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.
Palmer-Crocker
R L
RL
Program in Molecular Cardiobiology, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, CT 06536-0812.
Pober
J S
JS
D015815:Cell Adhesion Molecules / Q000096:biosynthesis*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000201:enzymology* / Q000276:immunology*; D005434:Flow Cytometry; D006801:Humans; D015151:Immunoblotting; D015847:Interleukin-4 / Q000502:physiology*; D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen / Q000096:biosynthesis; D014471:Umbilical Veins / Q000166:cytology; D019010:Vascular Cell Adhesion Molecule-1
D015815:Cell Adhesion Molecules; D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen; D019010:Vascular Cell Adhesion Molecule-1; D015847:Interleukin-4; D011505:Protein-Tyrosine Kinases