The first cytoplasmic loop of the thyrotropin receptor is important for phosphoinositide signaling but not for agonist‐induced adenylate cyclase activation

FEBS Letters

Kosugi, Shinji¹  Mori, Toru¹ 

[1] Department of Laboratory Medicine, Kyoto University School of Medicine, First Clinical Research Building, Room 223, 54-Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-01, Japan

关键词: Dual signaling;    cAMP signal;    PIP2 signal;    G protein;    Graves' disease;   

DOI  :  10.1016/0014-5793(94)80449-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We investigated the role of the 1st cytoplasmic loop of the thyrotropin receptor (TSHR) on signal transduction using mutants as we did the 2nd and 3rd cytoplasmic loops [Kosugi S. et al. (1994) Mol. Endocrinol., in press; and 7, 1009-1020]. Five substitution mutants involving the first cytoplasmic loop showed a TSH- or Graves' IgG-stimulated cAMP response despite the low TSH binding B _max. All the mutants completely lost or markedly decreased the TSH- or Graves' IgG-stimulated inositol phosphate increase. These findings suggest that the l st cytoplasmic loop of the TSHR does not play a crucial role in agonist-induced adenylate cyclase activation but that it is important for phosphoinositide signaling.

【 授权许可】

Unknown