Reversible defects in O-linked glycosylation and LDL receptor expression in a UDP-Gal UDP-GalNAc 4-epimerase deficient mutant

@article{Kingsley1986ReversibleDI,
  title={Reversible defects in O-linked glycosylation and LDL receptor expression in a 
 
 
 UDP-Gal
 
 
 UDP-GalNAc
 
 
 4-epimerase deficient mutant},
  author={David M. Kingsley and Karen F. Kozarsky and Lawrence Hobble and Monty Krieger},
  journal={Cell},
  year={1986},
  volume={44},
  pages={749-759}
}
We previously isolated an unusual hamster cell mutant (ldlD) that does not express LDL receptor activity unless it is cocultivated with other cells or grown in high concentrations of serum. We now show that ldlD cells are deficient in the enzyme UDP-galactose and UDP-N-acetylgalactosamine (GalNAc) 4-epimerase. When ldlD cells are grown in glucose-based media, they cannot synthesize enough UDP-galactose and UDP-GalNAc to allow normal synthesis of glycolipids and glycoproteins. The 4-epimerase… Expand
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References

SHOWING 1-10 OF 41 REFERENCES
Three types of low density lipoprotein receptor-deficient mutant have pleiotropic defects in the synthesis of N-linked, O-linked, and lipid- linked carbohydrate chains
TLDR
Comparisons between the ldl mutants and a large number of previously isolated CHO glycosylation defective mutants showed that the genetic defects in ldlB, ldlC, and ldlD cells were unique and that only very specific types of carbohydrate alteration could dramatically affect LDL receptor function. Expand
Addition of a mannose-6-phosphate-containing oligosaccharide alters cellular processing of low density lipoprotein by parental and LDL-receptor-defective Chinese hamster ovary cells.
TLDR
The potential use of M56P-LDL in the isolation of cells with pleiotropic mutations affecting receptor-mediated endocytosis is discussed, suggesting differences in the intracellular processing of mannose 6-phosphate-bearing ligands and LDL. Expand
Unusual forms of low density lipoprotein receptors in hamster cell mutants with defects in the receptor structural gene
TLDR
The finding of multiple mutant forms of the LDL receptor in ldlA mutants, some of which appeared together in the same cell, confirm that the ldnA locus is the structural gene for the LDL receptors. Expand
Biosynthesis of N- and O-linked oligosaccharides of the low density lipoprotein receptor.
TLDR
The studies suggest that the apparent differences in molecular weight between the precursor and mature forms of the LDL receptor are largely, if not entirely, due to the addition of sialic acid and galactose residues to the O-linked GalNAc residues. Expand
Receptor-mediated endocytosis of low density lipoprotein: somatic cell mutants define multiple genes required for expression of surface-receptor activity.
  • D. Kingsley, M. Krieger
  • Biology, Medicine
  • Proceedings of the National Academy of Sciences of the United States of America
  • 1984
TLDR
Results suggest that the ldlA locus is the structural gene for the LDL receptor in CHO cells, which must have defects in genes that are required for either the regulation, synthesis, transport, recycling, or turnover of LDL receptors. Expand
Deletion of clustered O-linked carbohydrates does not impair function of low density lipoprotein receptor in transfected fibroblasts.
TLDR
It is concluded that: 1) the serine- and threonine-rich region of the LDL receptor is the site for addition of clustered O-linked carbohydrates; 2) the receptor contains a small number of isolated chains of O- linked carbohydrates in addition to the clustered chains; and 3) the clustered O -linked carbohydrates are not essential for LDL receptor function in cultured hamster fibroblasts. Expand
Complementation of mutations in the LDL pathway of receptor-mediated endocytosis by cocultivation of LDL receptor-defective hamster cell mutants
TLDR
The induction and short-term stability of LDL receptors in cbc cells did not require protein synthesis by icc cells, suggesting that an unstable diffusible factor or intimate cell-to-cell association was required for complementation. Expand
The metabolism of d-galactosamine and N-acetyl-d-galactosamine in rat liver.
TLDR
Analysis of the [1-(14)C]glucosamine-containing disaccharides released from glycogen by beta-amylase provided additional evidence that they consist of a mixture of glucose and glucosamine in a 1:1 ratio, but with glucose predominating on the reducing end. Expand
Co-purification and characterization of UDP-glucose 4-epimerase and UDP-N-acetylglucosamine 4-epimerase from porcine submaxillary glands.
TLDR
Kinetic analysis reveals that the reactants for one reaction are competitive inhibitors of the other reaction, with the Ki values of the inhibitors essentially identical with their Km values as substrates, suggesting that UDP-glucose 4-epimerase and UDP-N-acetylglucosamine 4- epimerase activities reside in a single enzyme. Expand
Isolation of Chinese hamster cell mutants defective in the receptor-mediated endocytosis of low density lipoprotein.
TLDR
The procedure takes advantage of the unique structure of low density lipoprotein, a plasma cholesterol transport protein that enters cells by receptor-mediated endocytosis, and may have general utility in isolating cells with mutations affecting other receptor systems. Expand
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