title: Stimulation of protein glycosylation in cultured hepatoma cells by polyprenyl phosphates.
abstract: The aim of this work was to selectively stimulate N-glycosylation of proteins in cultured AH 70Btc hepatoma cells. Dolichyl phosphate, alpha-dihydrodecaprenyl phosphate and solanesyl phosphate were entrapped in egg lecithin liposomes and supplied to the cells. After treatment with 0.6-15 nmol of the polyprenyl phosphates/3 ml/dish for 48 hr, the incorporations of [14C]glucosamine into N-linked saccharide chains of glycoproteins and into lipid intermediates were increased to various extents. The stimulation by alpha-dihydrodecaprenyl phosphate was most significant and 15 nmol of the lipid/dish increased the incorporation into N-linked saccharide chains of glycoproteins by about 80%. The incorporations of [14C]glucosamine into O-linked saccharide chains and of [14C]leucine into proteins were not changed significantly by alpha-dihydrodecaprenyl phosphate. When the N-linked glycopeptides prepared from the cells and those from the cells treated with the polyprenyl phosphate were compared by Sephadex G-50 column chromatography, no significant difference was observed. Analysis of reduced cellular glycoproteins by sodium dodecyl sulfate/polyacrylamide-gel electrophoresis showed that alpha-dihydrodecaprenyl phosphate increased the incorporation of [14C]glucosamine into N-linked saccharide chains of certain high-molecular-weight glycoproteins. In addition, the polyprenyl phosphate enhanced the adhesiveness of the cells to the substratum, probably as a result of the stimulation of N-glycosylation of proteins.
mesh_terms: D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D004591:Electrophoresis, Polyacrylamide Gel; D005944:Glucosamine / Q000378:metabolism; D006017:Glycolipids / Q000378:metabolism; D006020:Glycopeptides / Q000096:biosynthesis; D006023:Glycoproteins / Q000096:biosynthesis*; D008114:Liver Neoplasms, Experimental / Q000378:metabolism*; D011105:Polyisoprenyl Phosphate Sugars / Q000378:metabolism; D011106:Polyisoprenyl Phosphates / Q000494:pharmacology*; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D051381:Rats; D013329:Structure-Activity Relationship; D013997:Time Factors
chemical_list: D006017:Glycolipids; D006020:Glycopeptides; D006023:Glycoproteins; D011105:Polyisoprenyl Phosphate Sugars; D011106:Polyisoprenyl Phosphates; D003994:Bucladesine; D005944:Glucosamine