Tyrosine phosphorylation of common and specific sets of cellular proteins rapidly induced by insulin, insulin-like growth factor I, and epidermal growth factor in an intact cell.

Abstract

KB cells respond to insulin and insulin-like growth factor I (IGF-I) in a closely similar way (induction of membrane ruffling, stimulation of pinocytosis, and amino acid transport) but respond to epidermal growth factors (EGF) in a similar but distinct way. In the KB cells, using phosphotyrosine-specific antibody we have found that: the receptors for insulin (beta subunit), IGF-I (beta subunit), and EGF undergo tyrosine phosphorylation as early as 10 s after addition of their respective ligands; a 185-kDa protein is rapidly (less than 10 s) tyrosine phosphorylated by insulin and IGF-I through their respective receptor kinases but not EGF; tyrosine phosphorylation of a 190-kDa glycoprotein is rapidly (less than 10 s) induced by EGF through EGF receptor kinase; and tyrosine phosphorylation of a 240-kDa protein is stimulated within 30 s by all three growth factors. These patterns of tyrosine phosphorylation could be causally related to biological responses induced by the three growth factors.