Coulonval K, Maenhaut C, Dumont J E, Lamy F
Institute of Interdisciplinary Research, Free University of Brussels, Belgium.
Exp Cell Res. 1997 Jun 15;233(2):395-8. doi: 10.1006/excr.1997.3582.
Thyrotropin (TSH) through the cAMP cascade and in the presence of insulin induces the proliferation of dog thyroid cells. In this work, it is shown that TSH via cAMP causes the phosphorylation of the three members of the pRb family, pRb, p107, and p130, with the same kinetics as those observed when these cells are stimulated by mitogens acting through a tyrosine kinase receptor or through activation of kinase C. It is the first described point of convergence of cAMP-dependent and -independent mitogenic pathways in dog thyrocytes and suggests that the phosphorylation of the three proteins may be involved in the initiation of DNA synthesis in these cells. We also show that insulin, which induces hypertrophy and is permissive for the TSH mitogenic action, does not provoke the phosphorylation of any pRb family member, suggesting that none of these phosphorylations is required for this effect.
促甲状腺激素（TSH）通过环磷酸腺苷（cAMP）级联反应并在胰岛素存在的情况下诱导犬甲状腺细胞增殖。在本研究中，结果表明TSH通过cAMP导致pRb家族的三个成员pRb、p107和p130发生磷酸化，其动力学与这些细胞受到通过酪氨酸激酶受体作用的有丝分裂原刺激或通过蛋白激酶C激活刺激时所观察到的相同。这是首次描述的犬甲状腺细胞中cAMP依赖性和非依赖性有丝分裂途径的交汇点，表明这三种蛋白质的磷酸化可能参与了这些细胞中DNA合成的起始过程。我们还表明，诱导肥大并允许TSH有丝分裂作用的胰岛素不会引起任何pRb家族成员的磷酸化，这表明这种作用不需要这些磷酸化中的任何一种。
