Two cell lines established from tumors of the head and neck area at different clinical stages were found to differ in the expression and in the tyrosine kinase activity of the epidermal growth factor (EGF) receptor. Cell line 183A was derived from an early-stage tumor and cell line 1483 was derived from a tumor that had metastasized to lymph nodes. The 1483 cells displayed a higher plating effi...

Transforming growth factor beta (TGF-beta) increased the phosphorylation of the epidermal growth factor (EGF) receptor and inhibited the growth of A431 cells. Incubation with TGF-beta induced maximal EGF receptor phosphorylation to levels 1.5-fold higher than controls. Phosphorylation increased more prominently (4-5-fold) on tyrosine residues as determined by phosphoamino acid analysis and anti...

Signalling by physiological levels of urea (e.g. 200 mM) in cells of the mammalian renal medulla is reminiscent of activation of a receptor tyrosine kinase. The epidermal growth factor (EGF) receptor may be transactivated by a variety of G-protein-coupled receptors, primarily through metalloproteinase-dependent cleavage of a membrane-anchored EGF precursor. In the murine inner medullary collect...

Epidermal growth factor (EGF) acts as a paracrine and autocrine mediator of cell proliferation differentiation in various types epithelial cells, such sebocytes, which produce the lipid-rich sebum to moisturize skin. However, lipids via direct contact by penetrating through epidermis may have regulatory roles on epidermal dermal cells well. As EGF receptor (EGFR) is expressed throughout prolife...

Adhesion of human primary skin fibroblasts and ECV304 endothelial cells to immobilized matrix proteins, beta1 or alphav integrin antibodies stimulates tyrosine phosphorylation of the epidermal growth factor (EGF) receptor. This tyrosine phosphorylation is transiently induced, reaching maximal levels 30 min after adhesion, and it occurs in the absence of receptor ligands. Similar results were ob...

This report describes analysis of factors which regulate the binding of EGF to EGF receptor, receptor internalization, and receptor recycling. Three different methods were used to inhibit high-affinity EGF binding as measured at equilibrium: treatment of cells with an active phorbol ester (PMA), binding of a mAb directed against the EGF receptor (mAb108), and truncation of most of the cytoplasm...

Epidermal growth factor (EGF) receptor protein has been purified in a single high-yield step by immunoaffinity chromatography of extracts of A431 cells. A monoclonal antibody directed against the EGF binding site of the receptor was immobilized to Sepharose 4B as a specific immune absorbent and competitive elution with EGF was used to obtain purified EGF receptor protein with tyrosine kinase ac...

Endogenous substrates of the EGF receptor have been described in transformed cells; however, little is known about substrates in normal tissue. To characterize epidermal growth factor (EGF) receptor phosphorylation and search for endogenous substrates in normal rat hepatocytes, cells were labeled with [32P]orthophosphate, and phosphotyrosine-containing proteins were sought by using a high-affin...

Binding of epidermal growth factor (EGF) to its receptor induces rapid internalization and degradation of both ligand and receptor via the lysosomal pathway. To study the mechanism of intracellular sorting of EGF-EGF receptor complexes to lysosomes, NIH 3T3 cells transfected with wild-type and mutant EGF receptors were employed. The kinetics of 125I-EGF trafficking was analyzed using low concen...