STAT Activation by Epidermal Growth Factor (EGF) and Amphiregulin REQUIREMENT FOR THE EGF RECEPTOR KINASE BUT NOT FOR TYROSINE PHOSPHORYLATION SITES OR JAK1

摘要: The epidermal growth factor (EGF) receptor activates several signaling cascades in response to the ligands EGF and amphiregulin (AR). One of these events involves tyrosine phosphorylation STATs (signal transducers activators transcription), a process believed require activation kinase JAK family. In this report we demonstrate that EGF- AR-induced STAT requires intrinsic activity but not presence Jak1. We show both wild type (WT) truncated receptors lacking all autophosphorylation sites activate 1, 3, 5 either or AR. Furthermore, relative cells expressing WT receptor, ligand-induced was enhanced only receptor. These results provide first evidence (i) receptor-mediated occurs Jak1-independent manner, (ii) is essential for activation, (iii) within are required activation.