Regulation and Dysregulation of Cardiac EC coupling by Calmodulin

摘要 小钙结合蛋白，钙调素(CaM)，直接控制，或至少调节 心内的功能。这种功能多样且普遍存在的钙结合蛋白是唯一已知的例外 生物学的中心法则--一种基因一种蛋白质。在所有哺乳动物细胞中，相同的CaM蛋白来自 三个不同的基因，CaM1，2和3。找到这种差异的原因不仅对解释这一点很重要 生物学难题，但为了了解CaM在各种细胞类型中介导的大量信号过程 包括健康和疾病中的心肌细胞。已知CaM可以结合和调节数百种靶蛋白。 由于CaM的游离浓度在心肌细胞内是有限的，而结合蛋白是 丰富，我们推测这三种不同基因的存在对于协调特定和独特的 心肌细胞钙调素介导的钙信号在空间和时间上的过程。我们提出了发散的5‘和3’UTRs 在三个CaM基因中，招募不同的RNA结合蛋白来运输和汇集特定的CaM 目标蛋白质的mRNAs形成离散的“相互作用小体”。我们假设这些信使核糖核酸簇是局部的 翻译在一起(“转染体”)，其中蛋白质在心肌细胞内发挥作用，因此 “功能上分散的”。我们创建了新的成像工具和数据分析软件，以便可视化 这些过程。我们还在成人心肌细胞中发现核糖体转运蛋白，粗面内质网， 高尔基复合体主动处理和翻译远离核周空间的跨膜蛋白， 与长期持有的膜蛋白翻译的经典观点相矛盾。在本提案中，我们将定义 三种CaM mRNAs的丰度、亚细胞分布、翻译位点和生理调节， 以及健康和疾病中心肌细胞中关键的CaM靶点。最终，我们将把这部小说和 以我们的治疗工程蛋白为靶点的新知识，具有高精度和特异性来选择 “互动小体”，以治疗各种心血管疾病。

Abstract The small Ca binding protein, calmodulin (CaM), either directly controls, or at minimum, modulates every functionality within the heart. This versatile and ubiquitous Ca binding protein is the only known exception to the central rule of biology - one gene one protein. In all mammalian cells, an identical CaM protein is derived from three different genes, CaM1,2 and 3. Finding the reason for this deviation is not only important to explain this biological conundrum, but for understanding the vast signaling processes mediated by CaM in various cell types including cardiac myocytes in health and disease. CaM is known to bind and regulate hundreds of target proteins. Due to the fact that the free concentration of CaM is limited within cardiac myocytes, yet the bound protein is abundant, we surmise the presence of the three different genes is important for orchestrating specific and unique myocyte CaM-mediated Ca signaling processes in space and time. We propose the divergent 5’ and 3’ UTRs of the three CaM genes recruit different RNA binding proteins used to transport and pool together specific CaM target proteins’ mRNAs into discrete “interactosomes”. We hypothesize these mRNA clusters are then locally translated together (“tranlatosomes”) where the proteins function within the cardiac myocyte and are thus “functionally distributed”. We have created novel imaging tools and data analysis software in order to visualize these processes. We have also discovered in the adult cardiac myocyte that ribosomal translocons, rough ER, and the golgi complex actively process and translate transmembrane proteins far from the perinuclear space, contradictory to the long held classical view of membrane protein translation. In this proposal, we will define the abundance, subcellular distribution, sites of translation and physiological modulation for the three CaM mRNAs, along with key CaM targets in cardiac myocytes in health and disease. Ultimately, we will apply this novel and new knowledge to target our therapeutically engineered proteins with high precision and specificity to select “interactosomes” in order to treat various cardiovascular diseases.