Involvement of Na+ and HCO in receptor-mediated endocytosis of α2-macroglobulin, epidermal growth factor, and vesicular stomatitis virus

✍ Scribed by Robert B. Dickson; Richard Schlegel; Mark C. Willingham; Ira H. Pastan

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 742 KB
• Volume: 113
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041130302

✦ Synopsis

Abstract

α~2~‐Macroglobulin (α~2~M), epidermal growth factor (EGF), and vesicular stomatitis virus (VSV) each enter cultured fibroblasts by receptor‐mediated endocytosis. The present study defines some basic ionic requirements in the cell culture medium which are necessary for the maximal rate of endocytosis of these three ligands. Na^+^ and HCO were both necessary for maximal endocytosis of ^125^I‐α~2~M, ^125^I‐EGF, and ^35^S‐VSV at 37°C. The ion specificities for both the anion and cation requirements were established. The binding of ^125^I‐α~2~M to its cellular receptors at 4°C was unaffected by the absence of Na^+^ and HCO in the culture medium. In addition, the absence of Na^+^ and HCO in the culture medium did not reduce cellular uptake of horseradish peroxidase by fluid phase endocytosis. Na^+^ and HCO may be general requirements in receptor‐mediated endocytosis.