FIGURE 5.

c-Met tyrosine kinase inhibition abrogates HGF-induced activation of S1PR1 and ITGB4 and EC barrier enhancement. A, HPAEC were pretreated with a c-Met inhibitor, XL880 (0.4 nmol/liter, 1 h) prior to HGF treatment (25 ng/ml, 5 min). Cell lysates were immunoprecipitated with an anti-c-Met antibody and then subjected to immunoblotting with antibodies specific for c-Met, ITGB4, or S1PR1. Phosphorylation corresponding to the same molecular weight was determined via repeat immunoblotting on the same membrane with specific antibodies as shown (representative blots shown, densitometry data expressed as fold change phosphorylation relative to control and normalized to total protein, n = 3/condition, *, p < 0.05 compared with HGF-treated control cells). B, maximal TER responses to HGF (25 ng/ml) were measured in cells pretreated with XL880 (0.4 nmol/liter, 1 h) and compared with untreated control cells (n ≥ 5/condition, *, p < 0.05).