title: EGF induces receptor down-regulation with no receptor recycling in KB cells.
abstract: Several ligands, including epidermal growth factor (EGF), have been found to negatively modulate or down-regulate their specific plasma membrane receptors. Using both 125I-EGF and a monoclonal antibody against the EGF-receptor (EGF-R1), we studied the down-regulation of the EGF-receptor in the human adenocarcinoma cell line KB. The results presented here demonstrate that incubating KB cells at 37 degrees C with EGF rapidly decreases the number of plasma membrane EGF-receptors. In addition, there is a concomitant rise of equal magnitude in the number of EGF molecules taken up. The latter result argues strongly that there is negligible recycling of the EGF-receptor in KB cells and that the major portion of internalized EGF-receptor complexes are transported to lysosomes and subsequently degraded. The fate of the EGF-receptor is markedly different from that of receptors not subject to down-regulation. The biochemical signals that operate to regulate such diverse receptor traffic in cells remains to be elucidated.
authors.forename: R M
authors.initials: RM
authors.lastname: Lyall
authors.forename: I
authors.initials: I
authors.lastname: Pastan
authors.forename: M C
authors.initials: MC
authors.lastname: Willingham
mesh_terms: D002277:Carcinoma; D004815:Epidermal Growth Factor / Q000378:metabolism / Q000494:pharmacology*; D066246:ErbB Receptors; D006801:Humans; D007624:KB Cells; D007700:Kinetics; D009062:Mouth Neoplasms; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism*
chemical_list: D011956:Receptors, Cell Surface; D004815:Epidermal Growth Factor; D066246:ErbB Receptors