Sphingosine 1-phosphate-mediated α1B-adrenoceptor desensitization and phosphorylation. Direct and paracrine/autocrine actions

► Sphingosine-1-phosphate induces α1B-adrenergic receptor phosphorylation. ► IGF-I and EGF also induce this effect and increase sphingosine kinase activity. ► A sphingosine kinase-1 dominant-negative mutant reduced growth factor action. ► Similar effects are produced by S1P1 receptor knockdown. ► Sphingosine-1-phosphate is an autocrine mediator in the growth factor's effects.