Perturbation of cellular calcium delays the secretion and alters the glycosylation of thyroglobulin in FRTL-5 cells.
Treatment of FRTL-5 cells with a Ca2+ ionophore, A23187, or a specific inhibitor of the endoplasmic reticulum Ca2+ ATPases, thapsigargin, delayed thyroglobulin secretion. The secreted thyroglobulin showed an increased electrophoretic mobility and a reduced sensitivity to neuraminidase. Only thyroglobulin that was still in the endoplasmic reticulum was sensitive to the Ca(2+)-perturbant drugs as shown by experiments in which the drugs were added at different times during a chase. Analysis of the carbohydrate chains by BioGel P4 showed that thyroglobulin secreted in the presence of the Ca(2+)-perturbants displayed an increased ratio high mannose/complex chains.
Di Jeso
B
B
Centro di Endocrinologia ed Oncologia Sperimentale del CNR, Università Federico II, Napoli, Italy.
Formisano
S
S
Ulianich
L
L
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006031:Glycosylation; D006596:Hexosaminidases / Q000378:metabolism; D007476:Ionophores / Q000494:pharmacology; D008358:Mannose / Q000032:analysis; D019158:N-Acetylneuraminic Acid; D009439:Neuraminidase / Q000378:metabolism; D011233:Precipitin Tests; D011402:Pronase / Q000378:metabolism; D051381:Rats; D019284:Thapsigargin / Q000494:pharmacology; D013954:Thyroglobulin / Q000737:chemistry / Q000378:metabolism*
D004791:Enzyme Inhibitors; D007476:Ionophores; D000001:Calcimycin; D019284:Thapsigargin; D013954:Thyroglobulin; D006596:Hexosaminidases; D009439:Neuraminidase; D011402:Pronase; D019158:N-Acetylneuraminic Acid; D008358:Mannose; D002118:Calcium