Identifying missing proteins (MPs) has been one of the critical missions of the Chromosome-Centric Human Proteome Project (C-HPP). Since 2012, over 30 research teams from 17 countries have been trying to search adequate and accurate evidence of MPs through various biochemical strategies. MPs mainly fall into the following classes: (1) low-molecular-weight (LMW) proteins, (2) membrane proteins, (3) proteins that contained various post-translational modifications (PTMs), (4) nucleic acid-associated proteins, (5) low abundance, and (6) unexpressed genes. In this study, kidney cancer and adjacent tissues were used for phosphoproteomics research, and 8962 proteins were identified, including 6415 phosphoproteins, and 44 728 phosphosites, of which 10 266 were unreported previously. In total, 75 candidate detections were found, including 45 phoshoproteins. GO analysis for these 75 candidate detections revealed that these proteins mainly clustered as membrane proteins and took part in nephron and kidney development. After rigorous screening and manual check, 9 of them were verified with the synthesized peptides. Finally, only one missing protein was confirmed. All mass spectrometry data from this study have been deposited in the PRIDE with identifier PXD006482.

中文翻译：

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肾脏癌磷酸化蛋白质组中缺失蛋白的鉴定

鉴定缺失的蛋白质（MPs）已成为以染色体为中心的人类蛋白质组计划（C-HPP）的关键任务之一。自2012年以来，来自17个国家/地区的30多个研究团队一直在尝试通过各种生化策略来寻找MP的充分而准确的证据。MP主要分为以下几类：（1）低分子量（LMW）蛋白，（2）膜蛋白，（3）包含各种翻译后修饰（PTM）的蛋白，（4）核酸相关蛋白，（5）低丰度和（6）未表达的基因。在这项研究中，将肾癌和邻近组织用于磷酸化蛋白质组学研究，鉴定出8962种蛋白质，包括6415种磷蛋白和44 728个磷酸位，其中10 266种以前未报道。总共发现了75种候选检测物，包括45种磷酸蛋白。GO对这75个候选检测物的分析表明，这些蛋白质主要聚集为膜蛋白，并参与了肾和肾脏的发育。经过严格的筛选和人工检查，其中的9种已用合成肽进行了验证。最终，仅确认了一种缺失的蛋白质。该研究的所有质谱数据已保存在PRIDE中，标识为PXD006482。