MULTIFUNCTIONAL CA++/CALMODULIN DEPENDENT PROTEIN KINASE

描述(研究人员摘要)：CaM激酶II是一种主要的 钙离子连接的信号转导系统；它使不同的 底物位于细胞质、细胞核、细胞骨架和细胞膜中 车厢。如果钙离子升高，反应的特异性是如何实现的 激活整个细胞内所有钙依赖的过程，如果CaM激酶 II通过将其所有底物磷酸化来回应？他们已经发现了时间 以及信号转导的空间元素，这可能使反应 钙调素蛋白激酶II的特异性。 时间调节：许多细胞刺激使该激酶处于振荡状态 细胞内钙离子浓度的变化。尽管信息被认为是 要在刺激频率中进行编码，以前没有频率解码器 已被确认身份。他们现在已经证明了CaM激酶II是敏感的 脉冲流对体外钙离子振荡频率的影响 一种在精确动力学下将固定化酶暴露在钙离子脉冲下的装置 控制，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，定义了 不同的步骤激活和去激活的频率 回应。他们将使用激酶结构作为有效的钙/钙调素的探针 浓度，以测试细胞钙调素是否限制和评估其 对频率响应的贡献。然后他们将测试Cam是否 肌动蛋白对细胞内钙离子振荡频率敏感 几个具有明确的钙信号通路和细胞内信号通路的细胞系 激酶的靶标。 空间调节：他们发现CaM激酶亚型是靶向的 到不同的细胞定位，细胞信号可以具有 基于其定位的对该激酶的优先调节。他们会 探索我们最近的发现，靶向一种核同工酶亚型 受钙离子依赖的自磷酸化以及 其他酶的磷酸化作用。他们将测试各种不同的能力 通过利用CaM工程细胞来实现细胞刺激的空间定向 以不同细胞定位为靶点的激酶II作为空间探针 细胞信号。信号转导通路可能既控制着细胞的激活 该激酶及其细胞内靶向，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.