Influence of Stim1 on TRPC post-translational modulation and cardiac hypertrophy

描述（由申请人提供）：典型瞬时受体电位（TRPC）通道与活化T细胞钙调磷酸酶核因子（Cn- NFAT）信号介导的适应性不良心肌肥厚有关。然而，通道活动的调控还没有得到很好的理解。我们的实验室已经报道了PKG磷酸化抑制TRPC6活性的一种调节机制。在HEK293细胞中的研究表明，TRPC通道的活性也可能通过基质相互作用蛋白1 （Stim1）的门控来调节，最近有报道称，Stim1在体内有助于肥厚反应。初步数据表明，Stim1和TRPC6通道偶联可能影响PKG通道的抑制作用。提出的工作有可能促进我们对心脏肥厚和随后的心力衰竭的分子机制的理解。通过更好地了解TRPC通道的调节，我们将了解治疗靶点的线索。TRPC通道在心脏病理实验和模型中很重要，在人类心脏病中也上调。我们假设STIM1与心肌细胞中的TRPC3和TRPC6通道相互作用，导致钙进入增加和由NFAT介导的肥厚信号传导。此外，我们提出心肌细胞中Stim1和TRPC3/6通道的偶联可以阻止PKG磷酸化。我们将通过检测离体心肌细胞中的钙内流来验证这一点，在体内我们将探索心脏肥大啮齿动物模型中Stim1和TRPC通道之间的相互作用。

DESCRIPTION (provided by applicant): Canonical transient receptor potential (TRPC) channels are linked in maladaptive cardiac hypertrophy mediated by calcineurin-nuclear factor of activated T cells (Cn- NFAT) signaling. Yet, the regulation of channel activity is not well understood. Our lab has reported on one regulatory mechanism of by which PKG phosphorylation inhibits TRPC6 activity. Studies in HEK293 cells indicate TRPC channel activity may also be modulated by gating of stromal interacting protein-1 (Stim1) which was recently reported to contribute to the hypertrophic response in vivo. Preliminary data suggests that Stim1 and TRPC6 channel coupling may influence PKG inhibition of the channel. The proposed work has the potential to advance our understanding of the molecular mechanisms of cardiac hypertrophy and subsequent heart failure. By better understanding the modulation of TRPC channels, which are important in experimental and models of cardiac pathology and are also upregulated in human heart disease, we will learn clues about targets for therapy. We hypothesize that STIM1 interacts with TRPC3 and TRPC6 channels in the cardiomyocyte leading to increased calcium entry and hypertrophic signaling mediated by NFAT. Additionally, we propose that the coupling of Stim1 and TRPC3/6 channels in the cardiomyocyte prevents PKG phosphorylation. We will test this by examining the calcium influx in isolated cardiomyocytes, and in vivo we will explore the interaction between Stim1 and TRPC channels in rodent models of cardiac hypertrophy.