In vivo modulation of annexins I, II and V expression by thyroxine and methylthiouracil.
Fiche publication
Date publication
décembre 1996
Journal
European journal of biochemistry
Auteurs
Membres identifiés du Cancéropôle Est :
Pr ANTONICELLI Franck, Dr EL BTAOURI Hassan
Tous les auteurs :
el Btaouri H, Claisse D, Bellon G, Antonicelli F, Haye B
Lien Pubmed
Résumé
Regulation of annexin concentration and localization were investigated in thyroid tissues of hypothyroid [methylthiouracil (MeSur) treatment], euthyroid (control) and hyperthyroid [thyroxine (T4) treatment] rats. A low level of circulating thyroid hormones induces a decrease of total thyroid calcium-binding protein concentration when compared with the concentration in unstimulated animals. Conversely, concentrations of annexins I, II and V increase. The accumulation of these proteins in two subcellular compartments (cytosolic and particulate fractions) can be reversed by addition of thyroid hormones. The finding of a specific increase in annexins concentration in thyroid-hormone-deficient rats, with a general decrease of the total calcium-binding protein content points to a very important role of these proteins in the cells. Furthermore, hyperthyroidisnt gives opposite results. To investigate the transduction pathway of annexins I-, II- and V-induced biosynthesis by thyroid hormones in thyroid glands, we used cultured pig thyroid cells as in vitro model system. In previous work [16], we have shown that annexin concentrations and localization are under TSH control via the adenylate cyclase pathway. In the presence of MeSur (in the culture medium), the protein-binding iodine remains low, indicative of weak thyroid hormone synthesis (data not shown) and that the annexins content is unchanged. These results suggest that, in thyroid tissue, an indirect mechanism links thyroid hormones to annexin expressions via the TSH feed-back loop, and excludes autocrine regulation.
Mots clés
Animals, Annexin A1, genetics, Annexin A2, metabolism, Annexin A5, metabolism, Calcium-Binding Proteins, metabolism, Cell Compartmentation, Cytosol, metabolism, Methylthiouracil, pharmacology, Rats, Rats, Wistar, Thyroid Gland, metabolism, Thyroxine, pharmacology, Triiodothyronine, metabolism, Up-Regulation
Référence
Eur. J. Biochem.. 1996 Dec;242(3):506-11