Increased osteoblastic c-fos expression by parathyroid hormone requires protein kinase A phosphorylation of the cyclic adenosine 3′,5′-monophosphate response element-binding protein at serine 133
Increased osteoblastic c-fos expression by parathyroid hormone requires protein kinase A phosphorylation of the cyclic adenosine 3′,5′-monophosphate response element-binding protein at serine 133
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DOI：
10.1210/en.140.3.1255
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发表时间：
1999-03-01
期刊：
影响因子：
4.8
通讯作者：
Partridge, NC
中科院分区：
文献类型：
--
作者：
Tyson, DR;Swarthout, JT;Partridge, NC
PTH 在成骨细胞中快速、短暂地诱导 c-fos 表达，并且需要 cAMP 反应元件结合蛋白 (CREB) 的活性。在这里，我们提供证据表明蛋白激酶 A (PKA) 是负责在丝氨酸 135 (S133) 处磷酸化 CREB 的酶，并且该事件是 PTH 诱导的 c-fos 表达所必需的。 PTH 以时间和剂量依赖性方式增加 CREB 在 S133 的磷酸化水平，与响应 PTH 的 PKA 激活时间和水平相关。 PTH-(1-34) 和 -(1-31) 均已知可激活 cAMP 通路，诱导 CREB 磷酸化并增加 c-fos 信使 RNA 的水平，而 PTH-(3-34)、-(13-34) 和 -(28-48) 则不能。钙/钙调蛋白依赖性蛋白激酶和蛋白激酶C的特异性抑制剂不能抑制响应PTH的CREB磷酸化或c-fos表达；然而，H-89（一种 PKA 特异性抑制剂）可以以剂量依赖性方式发挥作用。此外，通过转染PKA热稳定抑制剂，PTH诱导的c-fos启动子活性以剂量依赖性方式被完全抑制。总而言之，这些数据提供了强有力的证据，表明 PKA 是响应 PTH 负责在 S133 处磷酸化 CREB 的酶，并且 PKA 活性是 PTR 诱导的 c-fos 表达所必需的。
PTH induces c-fos expression rapidly and transiently in osteoblastic cells and requires the activity of the cAMP response element-binding protein (CREB). Here we provide evidence that protein kinase A (PKA) is the enzyme responsible for phosphorylating CREB at serine 135 (S133) and that this event is required for PTH-induced c-fos expression. PTH increases the level of phosphorylation of CREB at S133 in a time- and dose-dependent manner, correlating with the time and level of activation of PKA in response to PTH. PTH-(1-34) and -(1-31), each known to activate the cAMP pathway, induced the phosphorylation of CREB and increased the levels of c-fos messenger RNA, whereas PTH-(3-34), -(13-34), and -(28-48) could not. Specific inhibitors of calcium/calmodulin-dependent protein kinases and protein kinase C could not inhibit CREB phosphorylation or c-fos expression in response to PTH; however, H-89, a specific inhibitor of PKA, could do so in a dose-dependent manner. In addition, PTH-induced c-fos promoter activity was completely inhibited in a dose-dependent fashion by transfection of the heat-stable inhibitor of PKA. Taken together, these data provide strong evidence that PKA is the enzyme responsible for phosphorylating CREB at S133 in response to PTH and that PKA activity is required for PTR-induced c-fos expression.