Photoreceptor mitochondria and Ca2+ Dynamics

 描述(申请人提供)：钙离子(钙离子)介导的细胞内串扰对于理解细胞功能的调节是至关重要的。细胞内Ca~(2+)流量和线粒体Ca~(2+)动力学，影响参与能量代谢和细胞氧化还原的线粒体酶的活性。这些变化影响线粒体、细胞质和细胞核中蛋白质的翻译后修饰，这些蛋白质控制着细胞的能量代谢和转录等功能。我们推测，光感受器中线粒体的钙信号对它们的功能和生存至关重要。这里提出的这项研究将确定线粒体钙离子如何调节光感受器活性，以满足这种独特感觉神经元的特殊需求。利用遗传编码的钙指示剂和活体成像，我们记录了斑马鱼锥形感光细胞胞体和线粒体中巨大的钙波动。我们还开发了操纵细胞体和线粒体中的钙离子以及检测蛋白质修饰和细胞氧化还原变化的方法。我们将使用这些方法来确定线粒体如何处理光感受器内的钙离子流动。我们将研究线粒体如何调节光感受器细胞体中的钙离子，以及线粒体钙离子单一转运体的作用(目标1)。我们还将确定Ca~(2+)如何控制细胞质氧化还原电位和蛋白质的酰化(目标2)。

 DESCRIPTION (provided by applicant): Intracellular crosstalk mediated by calcium ions (Ca2+) is fundamentally important for understanding regulation of cellular function. Cellular Ca2+ fluxes and mitochondrial Ca2+ dynamics, influence the activity of mitochondrial enzymes involved in energy metabolism and cellular redox. These changes influence post-translational modification of proteins in mitochondria, the cytoplasm and the nucleus, which control cell functions such as energy metabolism and transcription. We hypothesize that Ca2+ signaling by mitochondria in photoreceptors is critical for their function and survival. The study proposed here will define how photoreceptor activity is regulated by mitochondrial Ca2+ to meet the specialized demands of this unique sensory neuron. Using genetically encoded Ca2+ indicators and in vivo imaging, we have documented large Ca2+ fluctuations in the cell bodies and mitochondria of zebrafish cone photoreceptors. We also developed methods for manipulating Ca2+ in cell bodies and mitochondria and for detecting protein modifications and cellular redox changes. We will use these methods to determine how Ca2+ fluxes within photoreceptors are processed by mitochondria. We will study how mitochondria regulate Ca2+ in photoreceptor cell bodies and the role of the mitochondrial Ca2+ uniporter (Aim 1). We also will determine how Ca2+ controls the cytoplasmic redox potential and acylation of proteins (Aim 2).