PDF(Pubmed)
Abstract：
Photoreceptor cells generate neuronal signals in response to capturing light. This process, called phototransduction, takes place in a highly specialized outer segment organelle. There are significant discrepancies in the reported amounts of many proteins supporting this process, particularly those of low abundance, which limits our understanding of their molecular organization and function. In this study, we used quantitative mass spectrometry to simultaneously determine the abundances of 20 key structural and functional proteins residing in mouse rod outer segments. We computed the absolute number of molecules of each protein residing within an individual outer segment and the molar ratio among all 20 proteins. The molar ratios of proteins comprising three well-characterized constitutive complexes in outer segments differed from the established subunit stoichiometries of these complexes by less than 7%, highlighting the exceptional precision of our quantification. Overall, this study resolves multiple existing discrepancies regarding the outer segment abundances of these proteins, thereby advancing our understanding of how the phototransduction pathway functions as a single, well-coordinated molecular ensemble.
摘要：
光感受器细胞响应于捕获光产生神经元信号。这个过程,叫做光传导，发生在高度专业化的外部细胞器中。报道的支持这一过程的许多蛋白质的数量存在显著差异，特别是那些丰度低的，这限制了我们对其分子组织和功能的理解。在这项研究中,我们使用定量质谱同时测定了小鼠杆外片段中20种关键结构和功能蛋白的丰度。我们计算了存在于单个外部片段中的每种蛋白质的分子的绝对数量以及所有20种蛋白质之间的摩尔比。在外片段中包含三个特征明确的组成型复合物的蛋白质的摩尔比与这些复合物的已建立的亚基化学计量比相差不到7％，突出了我们量化的非凡精度。总的来说,这项研究解决了关于这些蛋白质的外段丰度的多个现有差异，从而提高我们的理解光转导途径如何作为一个单一的功能，协调良好的分子系综。
