MULTIFUNCTIONAL CA++/CALMODULIN DEPENDENT PROTEIN KINASE

描述（研究者摘要）：CaM激酶II是一种主要的介导因子， Ca 2+连接的信号转导系统;它磷酸化不同的 位于细胞溶质、细胞核、细胞骨架和细胞膜中的底物 隔间 如果Ca 2+升高，如何实现反应特异性 激活整个细胞的所有Ca 2+依赖性过程，如果CaM激酶 II的反应是磷酸化所有的底物？ 他们发现时间 以及信号传导的空间要素， 特异性CaM激酶II。 时间调节：许多细胞刺激使激酶发生振荡 细胞内Ca ~（2+）浓度。 虽然信息被认为 为了被编码在刺激频率中，先前没有频率解码器 被识别。 他们现在已经证明，钙调蛋白激酶II是敏感的， 的频率的钙振荡在体外与使用脉冲流 在精确动力学条件下将固定化激酶暴露于Ca 2+脉冲的装置 他们现在可以利用它。 他们将检查分子 这一生化行为的基础，定义相对贡献的 激酶激活和失活的各个步骤 反应 他们将使用激酶构建体作为有效Ca 2 +/CaM的探针 浓度，以测试细胞CaM是否是限制性的，并评估其 对频率响应的贡献。 然后他们将测试CaM是否 激酶对Ca 2+振荡的频率敏感， 几种具有确定的Ca 2+信号传导途径和细胞内 激酶的靶点。 空间调节：他们发现CaM激酶亚型是靶向的， 不同的细胞定位，细胞信号可以有 基于其定位的激酶的优先调节。 他们将 探索我们最近的发现， 受Ca 2+依赖性自磷酸化调节， 其他激酶的磷酸化。 他们将测试各种能力， 通过用CaM工程化细胞来空间定向其信号的细胞刺激 激酶II靶向不同的细胞定位，作为空间探针， 细胞信号 信号转导通路既可以控制细胞的激活， 激酶及其胞内靶向，从而调节 细胞对刺激反应的特异性。

DESCRIPTION (Investigator's abstract): CaM kinase II is a major mediator of Ca2+ -linked signal transduction systems; it phosphorylates diverse substrates located in cytosolic, nuclear, cytoskeletal, and membrane compartments. How is response specificity achieved if any rise in Ca2+ activates all Ca2+ -dependen processes throughout the cell and if CaM kinase II responds by phosphorylating all its substrates? They have found temporal and spatial elements of signal transduction which may enable response specificity by CaM kinase II. Temporal regulation: Many cell stimuli subject the kinase to oscillations in the concentration of intracellular Ca2+. Although information is thought to be encoded in the stimulus frequency, no frequency decoder has previously been identified. They have now demonstrated that CaM kinase II is sensitive to the frequency of Ca2+ oscillations in vitro with the use of a pulse flow device that exposes immobilized kinase to Ca2+ pulses under precise kinetic control and which they can now exploit. They will examine the molecular basis for this biochemical behavior, defining the relative contribution of various steps in kinase activation and deactivation to the frequency response. They will use kinase constructs as probes of effective Ca2+/CaM concentration to test of whether cellular CaM is limiting and assess its contribution to the frequency response. They will then test whether CaM kinase is sensitive to the frequency of Ca2+ oscillations in situ using several cell lines with defined Ca2+ signaling pathways and intracellular targets of the kinase. Spatial regulation: They have found that CaM kinase isoforms are targeted to distinct cellular localization and that cell signals can have preferential regulation of the kinase based on its localization. They will explore our recent finding that targeting of a nuclear isoform of the kinase is regulated by Ca2+-dependent autophosphorylation as well as phosphorylation by other kinases. They will test the ability of various cell stimuli to spatially direc their signals by engineering cells with CaM kinase II targeted to distinct cellular localization as a spatial probe to cell signaling. Signal transductio pathways may both control activation of the kinase as well as its intracellula targeting and thereby regulate the specificity of cellular responses to stimulation.