The proteins secreted by human cells (collectively referred to as the secretome) are important not only for the basic understanding of human biology but also for the identification of potential targets for future diagnostics and therapies. Here, we present a comprehensive analysis of proteins predicted to be secreted in human cells, which provides information about their final localization in the human body, including the proteins actively secreted to peripheral blood. The analysis suggests that a large number of the proteins of the secretome are not secreted out of the cell, but instead are retained intracellularly, whereas another large group of proteins were identified that are predicted to be retained locally at the tissue of expression and not secreted into the blood. Proteins detected in the human blood by mass spectrometry–based proteomics and antibody-based immunoassays are also presented with estimates of their concentrations in the blood. The results are presented in an updated version 19 of the Human Protein Atlas in which each gene encoding a secretome protein is annotated to provide an open-access knowledge resource of the human secretome, including body-wide expression data, spatial localization data down to the single-cell and subcellular levels, and data about the presence of proteins that are detectable in the blood.

人细胞分泌的蛋白质（统称为分泌物组）不仅对于人类生物学的基本理解很重要，而且对于未来诊断和治疗的潜在靶标的识别也很重要。在这里，我们对预计在人体细胞中分泌的蛋白质进行全面分析，从而提供有关它们在人体中最终定位的信息，包括主动分泌到外周血中的蛋白质。分析表明，分泌蛋白的大量蛋白质不是分泌到细胞外，而是保留在细胞内，而鉴定出另一组蛋白质，预计它们将保留在表达组织中而不被分泌。进入血液。还介绍了通过基于质谱的蛋白质组学和基于抗体的免疫测定法在人血中检测到的蛋白质，并估算了其在血液中的浓度。结果显示在《人类蛋白质图集》的更新版本19中，其中注释了编码分泌蛋白的每个基因，以提供人类分泌蛋白的开放获取知识资源，包括全身表达数据，直至单细胞和亚细胞水平，以及有关血液中可检测到的蛋白质存在的数据。