Inhibition of N-glycan processing affects iodide organification in porcine thyroid cells.
The N-glycan-processing inhibitors swainsonine (Sw) and deoxymannojirimycin (dMM) were used to study the influence of N-glycans on iodide organification in cultured porcine thyroid cells. Incubations with [125I]NaI were followed by determination of labeled trichloroacetic acid-insoluble material in culture media, follicular contents and cells. In controls, most of this material was in the follicular contents. With Sw and dMM, total acid-insoluble material was less than 10% of control. Iodide uptake was slightly inhibited and hydrogen peroxide release was not affected by inhibitors. Cell-surface thyroid peroxidase (TPO) activity, assayed by its ability to iodinate bovine serum albumin, was strongly inhibited. Pronase glycopeptide analysis indicated that with drugs the content in complex-type N-glycans was strongly decreased while that in hybrid or oligomannosidic type was increased. In conclusion, inhibition of N-glycan processing prevents iodide organification in cultured porcine thyroid cells by decreasing the recovery of cell-surface TPO activity.
Long
Y
Y
Institut National de la Santé et de la Recherche Medicale (U 38), Faculté de Médecine, Marseilles, France.
Franc
J L
JL
Giraud
A
A
D017485:1-Deoxynojirimycin; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D003864:Depression, Chemical; D005944:Glucosamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism; D007453:Iodide Peroxidase / Q000096:biosynthesis; D007454:Iodides / Q000378:metabolism*; D008361:Mannosidases / Q000037:antagonists & inhibitors; D008565:Membrane Proteins / Q000096:biosynthesis; D011134:Polysaccharides / Q000378:metabolism*; D017026:Swainsonine; D013552:Swine; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
D000470:Alkaloids; D007454:Iodides; D008565:Membrane Proteins; D011134:Polysaccharides; D017485:1-Deoxynojirimycin; D006861:Hydrogen Peroxide; D007453:Iodide Peroxidase; D008361:Mannosidases; C046090:mannosyl-oligosaccharide 1,2-alpha-mannosidase; C038829:mannosyl-oligosaccharide 1,3 - 1,6-alpha-mannosidase; D005944:Glucosamine; D017026:Swainsonine