CELL STRETCH AND CARDIAC HYPERTROPHY

压力诱导的心脏拉伸，无论是在体内还是体外，都有 已被证明可以刺激合成代谢过程，包括增加 核糖体和蛋白质合成。在灌流的大鼠心脏中，牵张诱导 合成代谢反应与之同时发生，并依赖于 细胞内第二信使腺苷3‘，5’-的积累 环一磷酸(CAMP)与cAMP依赖蛋白激活 激活剂。该项目的持续目标是确定 细胞内第二次积累的分子要求 信使cAMP对细胞变形的反应。在结果出来之前 从这笔赠款资助的工作中，没有关于 特异性机械敏感元件的分离纯化 任何机械反应信号转导途径。在简单的环境中工作 S49小鼠淋巴瘤细胞低渗肿胀模型 描绘了负责的信号转导途径的组成部分 用于细胞变形后cAMP的积累。机械力 通过直接加速腺苷酸促进cAMP的积累 循环酶活性。这种刺激似乎独立于 鸟嘌呤核苷酸结合调节蛋白在细胞周期中的作用 腺酰环化酶活性的激素调节。目前没有 关于以下结构/功能关系的信息是可用的 赋予将变形刺激传递到世代的能力 一种细胞内信号。这就是本文提出的工作目标。 获取结构/功能信息的继续申请 腺苷环化酶。最近的研究表明，腺酰环化酶存在于 哺乳动物细胞中的多种异构体，到目前为止还没有特定的异构体 仅存在于机械反应的组织或细胞中。首字母 继续这一项目的工作包括确定， 机械反应细胞异构体的克隆和测序。一次 这些和其他异构体被克隆，它们在细胞中表达， 缺乏机械反应的cAMP积累，并进行测试以确定 腺酰环化酶中机械反应表型的保守性 一家人。到目前为止，已经测试了I型和III型亚型， 只有I型表现出机械反应行为。一旦异构体被 对机械反应进行了测序和测试，保守和发散 将确定结构并选择与以下内容相关的域 这是一处房产。这些保守结构域的遗传操作和 突变的腺酰环化酶在细胞系统中的后续表达 上面描述的将用于测试这些域的参与度 在机械反应行为中。

Pressure-induced stretch in the heart, both in vivo and in vitro, has been shown to stimulate anabolic processes including increased rates of ribosome and protein synthesis. In perfused rat hearts, stretch-induced anabolic responses occur concurrent with and are dependent upon accumulation of the intracellular second messenger adenosine 3', 5'- cyclic monophosphate (cAMP) and activation of cAMP-dependent protein kinase. It has been the continuing goal of this project to identify the molecular requirements for accumulation of the intracellular second messenger cAMP in response to cell deformation. Prior to the results from work funded by this grant, no information was available regarding the isolation and purification of the specific mechanosensitive element of any mechanoresponsive signal transduction pathway. Work in a simple cell model, hypotonic swelling of S49 mouse lymphoma cells, has delineated the components of a signal transduction pathway responsible for cAMP accumulation following cell deformation. Mechanical forces stimulate cAMP accumulation through direct acceleration of adenylyl cyclase activity. This stimulation appears to occur independent of the action of the guanine nucleotide-binding regulatory proteins involved in hormonal regulation of adenylyl cyclase activity. Currently no information is available as to the structure/function relationships which impart the capacity to transduce deformation stimuli into the generation of an intracellular signal. It is the goal of the work proposed in this continuation application to obtain structure/function information for adenylyl cyclase. Recent work has shown that adenylyl cyclase exists in multiple isoforms in mammalian cells, with no specific isoform thus far being exclusively found in mechanoresponsive tissues or cells. Initial work on the continuation of this project has involved identifying, cloning, and sequencing of isoforms from mechanoresponsive cells. Once these and other isoforms are cloned, they are expressed in cells which lack mechanoresponsive cAMP accumulation and tested to determine the conservation of the mechanoresponsive phenotype in the adenylyl cyclase family. Thus far, Type I and Type III isoforms have been tested, with only Type I demonstrating mechanoresponsive behavior. Once isoforms are sequenced and tested for mechanoresponsiveness, conserved and divergent structures will be identified and domains selected which correlate to this property. Genetic manipulation of these conserved domains and subsequent expression of mutated adenylyl cyclases in the cell systems described above will be used to test the participation of these domains in mechanoresponsive behavior.