Regulatory Mechanism of p66 Shc Expression by TSH in FRTL-5 Cells.
- Author:
Young Joo PARK
1
;
Eun Shin PARK
;
Tae Yong KIM
;
Yun Yong LEE
;
Seon Hwa LEE
;
Do Joon PARK
;
Chan Soo SHIN
;
Kyoung Soo PARK
;
Seong Yeon KIM
;
Hong Kyu LEE
;
Bo Youn CHO
Author Information
1. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
- Publication Type:Original Article
- Keywords:
Goiter;
p66shc;
TSH;
FRTL-5 cell
- MeSH:
Adenylyl Cyclases;
Antibodies, Blocking;
Cholera Toxin;
Goiter;
Pertussis Toxin;
Phospholipases;
Phosphotransferases;
Receptors, Thyrotropin;
RNA, Messenger;
Thyroid Gland
- From:Journal of Korean Society of Endocrinology
2003;18(1):45-55
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: Thyroid goiters are very common, however, the mechanism of development is not fully understood. A TSH receptor has been known to activate two different signaling pathways the cAMP/protein kinase A(PKA) and phospholipase C(PLC)/protein kinase C(PKC) systems. However, both systems are limited in the degree to which they explain the discrepancy between a goiter and TSH receptor activation. It has recently been reported that the expression of p66 Shc was increased by TSH stimulation in thyrocytes, suggesting that the p66 Shc molecule may play a critical role in the transition of the TSH-induced growth signals. METHODS AND RESULTS: In this study, we examined the expression of p66 Shc by stimulation of TSH, and the regulatory mechanisms of the TSH-induced expression of the p66 Shc in FRTL-5 cells. In FRTL-5 cells, TSH could increase the expression of the p66 Shc, and the this expression was decreased to basal levels after the removal of TSH. The TSH-induced p66 Shc expression was competitively inhibited by TSH receptor blocking antibodies. The increments of the expression of the p66 Shc protein caused by TSH were both time and concentration dependent, and it was same in the mRNA levels. Cholera toxin increased the expression of the p66 Shc, while pertussis toxin did not. The activators of the cAMP/PKA pathway (8-bromo-cAMP and forskolin) also stimulated the expression of p66 Shc, and the PKA inhibitor H89 decreased the expression, while the inhibition of the PKC pathway by GF109203X, or PMA, affected the expression of p66 Shc very little. CONCLUSION: Our data suggests that p66 Shc may play an important role in regulating the growth of thyrocytes. The TSH receptor - Gs protein - adenylate cyclase - cAMP - PKA pathway mainly mediates the TSH effects on the expression of p66 Shc molecules.
