Number of EGFR [Epidermal Growth Factor Receptor] in hepatocyte

Range in perfused liver 150,000: in vitro ~300,000 molecules/cell
Organism Rat Rattus norvegicus
Reference Dunn WA, Hubbard AL. Receptor-mediated endocytosis of epidermal growth factor by hepatocytes in the perfused rat liver: ligand and receptor dynamics. J Cell Biol. 1984 Jun98(6):2148-59. abstract & p.2157 right column bottom paragraphPubMed ID6327725
Method Abstract: "[Investigators] have used biochemical and morphological techniques to demonstrate that hepatocytes in the perfused liver bind, internalize, and degrade substantial amounts of murine epidermal growth factor (EGF) via a receptor-mediated process...Cytochemical localization using EGF coupled to horseradish peroxidase (EGF-HRP) revealed that the receptors were distributed along the entire sinusoidal and lateral surfaces of hepatocytes."
Comments Abstract: "Before ligand exposure, about 300,000 high-affinity receptors were detectable per cell, displayed no latency, and co-distributed with conventional plasma membrane markers." P.2157 right column bottom paragraph: "Exposure to EGF [Epidermal Growth Factor] Induces a Rapid Disappearance of Cell Surface EGF Receptors-[Investigators] measured 150,000 receptors per cell in the perfused liver and 300,000 receptors per cell in vitro. At present [they] don't understand the basis for this two-fold difference, but [they] believe, for several reasons, that the increased number found in liver homogenates represents receptors at the plasma membrane and not those in an intracellular pool. First, the binding in naïve cells displays no latency, whereas [they] can detect latent receptors in cells actively endocytosing EGF. Second, all the binding activity in naïve cells migrates on sucrose gradients with conventional plasma membrane markers, not internal membrane markers. Finally, the initial rapid wave of EGF clearance results in the uptake of about 300,000 ligand molecules, suggesting that all the receptors detected in vitro (300,000/cell) are in a functionally equivalent pool or site."
Entered by Uri M
ID 112725