Matthews R P, Guthrie C R, Wailes L M, Zhao X, Means A R, McKnight G S
Department of Pharmacology, University of Washington, Seattle 98195.
Mol Cell Biol. 1994 Sep;14(9):6107-16. doi: 10.1128/mcb.14.9.6107-6116.1994.
Phosphorylation of CREB (cyclic AMP [cAMP]- response element [CRE]-binding protein) by cAMP-dependent protein kinase (PKA) leads to the activation of many promoters containing CREs. In neurons and other cell types, CREB phosphorylation and activation of CRE-containing promoters can occur in response to elevated intracellular Ca2+. In cultured cells that normally lack this Ca2+ responsiveness, we confer Ca(2+)-mediated activation of a CRE-containing promoter by introducing an expression vector for Ca2+/calmodulin-dependent protein kinase type IV (CaMKIV). Activation could also be mediated directly by a constitutively active form of CaMKIV which is Ca2+ independent. The CaMKIV-mediated gene induction requires the activity of CREB/ATF family members but is independent of PKA activity. In contrast, transient expression of either a constitutively active or wild-type Ca2+/calmodulin-dependent protein kinase type II (CaMKII) fails to mediate the transactivation of the same CRE-containing reporter gene. Examination of the subcellular distribution of transiently expressed CaMKIV and CaMKII reveals that only CaMKIV enters the nucleus. Our results demonstrate that CaMKIV, which is expressed in neuronal, reproductive, and lymphoid tissues, may act as a mediator of Ca(2+)-dependent gene induction.
环磷酸腺苷（cAMP）依赖性蛋白激酶（PKA）对CREB（环磷酸腺苷反应元件结合蛋白）的磷酸化作用可激活许多含有CRE的启动子。在神经元和其他细胞类型中，细胞内Ca2+浓度升高可导致CREB磷酸化及含CRE启动子的激活。在通常缺乏这种Ca2+反应性的培养细胞中，通过导入IV型钙/钙调蛋白依赖性蛋白激酶（CaMKIV）的表达载体，我们赋予了含CRE启动子的Ca(2+)介导的激活作用。激活作用也可由Ca2+非依赖性的组成型活性形式的CaMKIV直接介导。CaMKIV介导的基因诱导需要CREB/ATF家族成员的活性，但不依赖PKA活性。相反，组成型活性或野生型II型钙/钙调蛋白依赖性蛋白激酶（CaMKII）的瞬时表达均不能介导相同的含CRE报告基因的反式激活。对瞬时表达的CaMKIV和CaMKII的亚细胞分布的研究表明，只有CaMKIV进入细胞核。我们的结果表明，在神经、生殖和淋巴组织中表达的CaMKIV可能作为Ca(2+)依赖性基因诱导的介质。
