title: Cellular localization of the activated EGFR determines its effect on cell growth in MDA-MB-468 cells.
abstract: The epidermal growth factor (EGF) receptor (EGFR) is a ubiquitously expressed receptor tyrosine kinase that regulates diverse cell functions that are dependent upon cell type, the presence of downstream effectors, and receptor density. In addition to activating biochemical pathways, ligand stimulation causes the EGFR to enter the cell via clathrin-coated pits. Endocytic trafficking influences receptor signaling by controlling the duration of EGFR phosphorylation and coordinating the receptor's association with downstream effectors. To better understand the individual contributions of cell surface and cytosolic EGFRs on cell physiology, we used EGF that was conjugated to 900 nm polystyrene beads (EGF-beads). EGF-beads can stimulate the EGFR and retain the activated receptor at the plasma membrane. In MDA-MB-468 cells, a breast cancer cell line that over-expresses the EGFR, only internalized, activated EGFRs stimulate caspase-3 and induce cell death. Conversely, signaling cascades triggered from activated EGFR retained at the cell surface inhibit caspase-3 and promote cell proliferation. Thus, through endocytosis, the activated EGFR can differentially regulate cell growth in MDA-MB-468 cells.
authors.affiliation: Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd, Oklahoma City, OK 73190, USA.
authors.forename: Dustin C
authors.initials: DC
authors.lastname: Hyatt
authors.forename: Brian P
authors.initials: BP
authors.lastname: Ceresa
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000737:chemistry / Q000188:drug therapy* / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D004705:Endocytosis / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000737:chemistry / Q000494:pharmacology*; D066246:ErbB Receptors / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D008024:Ligands; D008863:Microspheres; D021381:Protein Transport / Q000187:drug effects; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D008024:Ligands; D011994:Recombinant Proteins; D004815:Epidermal Growth Factor; C512478:EGFR protein, human; D066246:ErbB Receptors