Mannosylation of glycoproteins and dolichol derivatives in fibroblasts from patients with cystic fibrosis.
Increased incorporation of mannose into endogenous glycoprotein fractions has been found in whole cell lysates and crude membrane preparations of cultured skin fibroblasts from patients with cystic fibrosis (1.3-2.3-times normal) when GDP[14C]mannose served as the mannosyl donor. In contrast, the incorporation of mannose from GDPmannose into lipid fractions containing dolichol phosphate and dolichol pyrophosphate oligosaccharides as well as the incorporation of mannose from dolichol phospho[3H]mannose into both glycoproteins and dolichol derivatives were not significantly different among cell preparations from patients with cystic fibrosis and normal controls. Mannosyltransferase activity toward exogenous glycoproteins as well as the activities of soluble and membranous alpha-mannosidase and beta-mannosidase appeared to be normal and could not account for the observed differences. The altered incorporation of mannose into endogenous glycoprotein may reflect changes in glycosylation processes other than mannosylation.
D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003550:Cystic Fibrosis / Q000378:metabolism*; D004288:Dolichol Phosphates / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D006023:Glycoproteins / Q000096:biosynthesis*; D006155:Guanosine Diphosphate Mannose / Q000378:metabolism*; D006801:Humans; D008361:Mannosidases / Q000378:metabolism; D008364:Mannosyltransferases / Q000378:metabolism; D009702:Nucleoside Diphosphate Sugars / Q000378:metabolism*; D011104:Polyisoprenyl Phosphate Oligosaccharides / Q000378:metabolism; D012867:Skin / Q000378:metabolism*
D004288:Dolichol Phosphates; D006023:Glycoproteins; D009702:Nucleoside Diphosphate Sugars; D011104:Polyisoprenyl Phosphate Oligosaccharides; D006155:Guanosine Diphosphate Mannose; D008364:Mannosyltransferases; D008361:Mannosidases