Spatial organization of EGF receptor transmodulation by PDGF.
Even though the modulation of EGF receptors by PDGF is well documented, it is not known where on the cell surface cross-talk between the two receptor systems takes place. The recent finding that both populations of receptors are concentrated in cell surface caveolae suggestes that the confinement of the two receptors to this space might facilitate their interaction. Here we show that stimulation of PDGF receptors in caveolae with PDGF causes a subpopulation of EGF receptors in the same membrane fraction to become phosphorylated on tyrosine. Coincident with tyrosine phosphorylation, the binding of EGF to its receptor markedly declines. Loss of EGF binding is partially blocked by tyrosine kinase inhibitors. Despite the close proximity of the two receptors in caveolae, we saw no evidence that EGF could stimulated PDGFR tyrosine phosphorylation. These results suggest that these two receptor systems are highly organized in caveolae.
Liu
P
P
Department of Cell Biology and Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, 75235-9039, USA.
Anderson
R G
RG
D002462:Cell Membrane / Q000737:chemistry / Q000648:ultrastructure; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000378:metabolism; D066246:ErbB Receptors / Q000737:chemistry / Q000378:metabolism*; D005347:Fibroblasts / Q000648:ultrastructure; D019833:Genistein / Q000494:pharmacology; D006801:Humans; D007163:Immunosorbent Techniques; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D015398:Signal Transduction; D013329:Structure-Activity Relationship
D004791:Enzyme Inhibitors; D010982:Platelet-Derived Growth Factor; D019000:Phosphotyrosine; D004815:Epidermal Growth Factor; D019833:Genistein; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases