Activation of cyclic AMP-dependent kinase is required but may not be sufficient to mimic cyclic AMP-dependent DNA synthesis and thyroglobulin expression in dog thyroid cells
Activation of cyclic AMP-dependent kinase is required but may not be sufficient to mimic cyclic AMP-dependent DNA synthesis and thyroglobulin expression in dog thyroid cells
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DOI：
10.1128/mcb.17.11.6717
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发表时间：
1997-11-01
影响因子：
5.3
通讯作者：
Maenhaut, C
中科院分区：
文献类型：
--
作者：
Dremier, S;Pohl, V;Maenhaut, C
促甲状腺激素（TSH）通过环腺苷酸（cAMP）依赖性途径诱导犬甲状腺细胞胞质收缩、增殖和分化表达。通过微量注射活细胞，研究了cAMP依赖性蛋白激酶（PKA）在促甲状腺细胞胞质收缩、增殖和分化表达中的作用。证明PKA的活化在该过程中是必需的，通过显微注射表达质粒pC α ev或纯化的PKA催化（C）亚基本身，使PKA催化（C）亚基过表达，足以模拟cAMP。C亚基与调节亚基共注射时，未观察到cAMP依赖的形态学效应为了模拟cAMP诱导的PKA解离成游离C和R亚基，将C亚基与调节缺陷的截短的RI亚基共注射，（RI Delta 1-95）或与野生型RT或天然RII亚基一起孵育，然后与浓度太低而不能单独刺激cAMP依赖性事件的TSH一起孵育，虽然cAMP依赖的形态学变化仍然观察到，既不刺激DNA合成也不刺激Tg表达在这些细胞中，总之，这些数据表明，除了PRA激活，另一个cAMP依赖的机制可能存在，并在甲状腺细胞中的cAMP信号转导中发挥重要作用。
Thyrotropin (TSH), via a cyclic AMP (cAMP)-dependent pathway, induces cytoplasmic retractions, proliferation, and differentiation expression in dog thyroid cells, The role of cAMP-dependent protein kinase (PKA) in the induction of these events was assessed by microinjection into living cells, Microinjection of the heat-stable inhibitor of PKA (PKI) inhibited the effects of TSH, demonstrating that activation of PKA was required in this process, Overexpression of the catalytic (C) subunit of PKA brought about by microinjection of the expression plasmid pC alpha ev or of purified C subunit itself was sufficient to mimic the cAMP-dependent cytoplasmic changes and thyroperoxidase mRNA expression but not to induce DNA synthesis and thyroglobulin (Tg) expression, The cAMP-dependent morphological effect was not observed when C subunit was coinjected with the regulatory subunit (RI or RII subunit) of PKA, To mimic the cAMP-induced PKA dissociation into free C and R subunits, the C subunit was coinjected with the regulation-deficient truncated RI subunit (RI Delta 1-95) or with wild-type RT or native RII subunits, followed by incubation with TSH at a concentration too low to stimulate the cAMP-dependent events by itself, Although the cAMP-dependent morphology changes were still observed, neither DNA synthesis nor Tg expression was stimulated in these cells, Taken together, these data suggest that in addition to PRA activation, another cAMP-dependent mechanism could exist and play an important role in the transduction of the cAMP signal in thyroid cells.