Transport and intracellular distribution of copper in a human hepatoblastoma cell line, HepG2

✍ Scribed by Richard J. Stockert; Phyllis S. Grushoff; Anatol G. Morell; Glenn E. Bentley; Harold A. O'Brien; I. Herbert Scheinberg; Irmin Sternlieb

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 577 KB
• Volume: 6
• Category: Article
• ISSN: 0270-9139
• DOI: 10.1002/hep.1840060112

✦ Synopsis

The uptake of radiocopper by HepGZ cells is a saturable, temperature-dependent and cellular energy-independent process with a V,, of 7.1 f 0.2 pmoles min-' mg protein-' and an estimated K, of 3.3 f 0.5 wM. The rate of copper uptake is reduced at an equimolar concentration of albumin and is unaffected by zinc at a 10fold molar excess. Approximately 70% of the newly incorporated radiocopper binds to membranes and organelles, while 30% is recovered in the cytosol. The soluble fraction can be resolved into two copper-binding protein peaks. Incubation of HepGZ with nonisotopic copper results in displacement of radiocopper associated with the proteins contained in the lower molecular weight peak. Exposure of the cells to cycloheximide inhibits the incorporation of the isotope into this fraction.