Tyrosine phosphorylation of mitogen-activated protein kinase in cells with tyrosine kinase-negative epidermal growth factor receptors.
Epidermal growth factor (EGF) treatment of cells expressing the human EGF receptor (EGFr) results in rapid tyrosine phosphorylation of several cellular proteins including mitogen-activated protein (MAP) kinase. EGF treatment of cells expressing a tyrosine kinase-inactive EGFr failed to induce the tyrosine phosphorylation of endogenous substrates in response to EGF; however, the tyrosine phosphorylation and activation of MAP kinase did occur. This observation indicates that MAP kinase is activated in response to a signal other than the tyrosine kinase activity of the EGFr. Because EGF does not stimulate cells expressing the inactive EGFr to proliferate, phosphorylation of MAP kinase may not be sufficient for the EGF-dependent mitogenesis.
Campos-González
R
R
Department of Biochemistry, University of Kentucky, Lexington 40536-0093.
Glenney
J R
JR
D015153:Blotting, Western; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002478:Cells, Cultured; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000378:metabolism*; D008934:Mitogens; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
D008934:Mitogens; D014443:Tyrosine; D011494:Protein Kinases; D066246:ErbB Receptors; D017871:Calcium-Calmodulin-Dependent Protein Kinases