Dissecting a post-translational modification code in cardiac reprogramming

在发育和进化过程中，细胞命运的改变是由细胞改变其转录水平的能力决定的 对蛋白质和染色质进行翻译后修饰(PTM)。组蛋白的PTM有 作为一种编码系统被广泛研究以指导细胞可塑性和细胞命运的改变，例如 差异化/程序化和去分化/再程序化。组蛋白PTM编码系统包括 磷酸化、乙酰化、甲基化和依赖于ATP的染色质重塑。同时，免费的PTMS 蛋白质，如转录因子的磷酸化和乙酰化，对器官也是必不可少的。 发育和细胞分化。组蛋白和游离蛋白中的这些PTM通常是由 相同的表观遗传酶，强烈表明组蛋白和组蛋白之间存在PTM编码的动态相互作用 表观遗传和转录因子。然而，很少有人进行系统的研究来定义 作为编码系统的PTMS的功能输出。此外，PTMS对两者的潜在协同效应 组蛋白和游离因子在细胞命运变化中的研究很少。因此，对PTM有深刻的认识 两种游离蛋白质上的密码(即关键的心脏转录因子和表观遗传因子)和组蛋白以及如何 他们的合作将导致对细胞命运决定和心脏重新编程的新见解。 我们对心脏重编程的研究发现了14-3-3结合的独特的磷酸化密码 图案(PC14-3-3)。我们假设14-3-3结合基序中的磷酸化代码的激活触发了 含有重编程因子的PC14-3-3之间的蛋白质-蛋白质相互作用组重排，表观遗传学 因子和染色质，它们在刺激心脏重编程方面协同工作。具体目标： 目的1：确定心脏重编程所必需的含有PC14-3-3的关键因子。我们将测试 假设PC14-3-3在关键的重编程、表观遗传和组蛋白蛋白中发挥关键作用 重新编程。这些研究将为PC14-3-3在心脏重编程中的应用奠定基础。 目的：探讨PC14-3-3在刺激心脏重编程中的分子机制。我们 将检验PC14-3-3激活触发PC14-3-3之间的蛋白质-蛋白质动态相互作用的假设 包含重编程因子(MEF2C和GATA4)、表观遗传因子(HDAC4和BRG1)和组蛋白的编码 H3(H3S10和H3S28)。这些研究将建立PC14-3-3导向的表观遗传和染色质景观 驱动心脏重编程的变化。 目的3：研究PC14-3-3引导下的心脏重编程治疗应用。我们会 验证PC14-3-3刺激人类细胞心脏重编程的假设及其临床意义 动物模型。这些研究将为PC14-3-3密码在心脏疾病中的临床前应用奠定基础。 重新编程，并为重新编程介导的心脏修复建立一个新颖而高效的平台。

During development and evolution, cell fate changes are guided by cell’s ability to change its transcriptional program with posttranslational modifications (PTMs) on both proteins and chromatin. PTMs of histones have been extensively studied as a coding system to guide alterations in cell plasticity and cell fate, such as differentiation/programming and de-differentiation/reprogramming. The histone PTM coding system includes phosphorylation, acetylation, methylation, and ATP-dependent chromatin remodeling. In parallel, PTMs of free proteins, such as phosphorylation and acetylation of transcription factors, are also essential for organ development and cell differentiation. These PTMs in both histones and free proteins are often catalyzed by the same set of epigenetic enzymes, strongly suggesting a dynamic interplay of PTM coding between histones and epigenetic and transcription factors. However, few systematic studies have been pursued to define the functional output of PTMs as a coding system. Furthermore, the potential synergistic effect of PTMs on both histones and free factors in cell fate changes are poorly explored. Therefore, a deep understanding of the PTM code on both free proteins (ie. key cardiac transcription factors and epigenetic factors) and histones and how they work together will lead to novel insights into cell fate determination and cardiac reprogramming. Our investigation of cardiac reprogramming uncovered a unique phosphorylation code in 14-3-3 binding motifs (PC14-3-3). We hypothesize that activation of a phosphorylation code in 14-3-3 binding motifs triggers a re-arrangement of protein-protein interactome among PC14-3-3 containing reprogramming factors, epigenetic factors, and chromatin, which work synergistically in stimulating cardiac reprogramming. Specific aims: Aim 1: Identify the key factors containing PC14-3-3 essential for cardiac reprogramming. We will test the hypothesis that PC14-3-3 in key reprogramming, epigenetic and histone proteins plays a critical role in reprogramming. These studies will build a knowledge foundation of PC14-3-3 in cardiac reprogramming. Aim 2: Determine PC14-3-3 guided molecular mechanism in stimulating cardiac reprogramming. We will test the hypothesis that PC14-3-3 activation triggers a protein-protein dynamic interplay among PC14-3-3 code containing reprogramming factors (Mef2c and Gata4), epigenetic factors (Hdac4 and Brg1), and histones H3 (H3S10 and H3S28). These studies will establish PC14-3-3 directed epigenetic and chromatin landscape changes in driving cardiac reprogramming. Aim 3: Examine PC14-3-3-guided cardiac reprogramming toward therapeutic applications. We will test the hypothesis that PC14-3-3 stimulates cardiac reprogramming in human cells and clinically relevant animal models. These studies will establish the pre-clinical application of PC14-3-3 code in cardiac reprogramming and build a novel and efficient platform for reprogramming-mediated heart repair.