TAILS N-terminomics of human platelets reveals pervasive metalloproteinase-dependent proteolytic processing in storage
TAILS N-terminomics of human platelets reveals pervasive metalloproteinase-dependent proteolytic processing in storage
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DOI：
10.1182/blood-2014-04-569640
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发表时间：
2014-12-18
期刊：
影响因子：
20.3
通讯作者：
Overall, Christopher M.
中科院分区：
文献类型：
--
作者：
Prudova, Anna;Serrano, Katherine;Overall, Christopher M.
蛋白水解酶，特别是金属蛋白酶，已被认为与输血前储存过程中的血小板功能丧失有关，但其潜在的机制仍不清楚。我们使用了一种专门的N末端组学技术，即底物的iTRAQ末端胺同位素标记(TIL)，来表征在血库条件下保存9天的血小板的N末端组、蛋白质组和翻译后修饰。从已鉴定的2938个蛋白质和7503个独特的多肽中，我们研究了人血小板中蛋白质的N-末端蛋氨酸切除、共翻译和翻译后N-α乙酰化、蛋白质成熟和蛋白质降解过程。我们还首次鉴定了10种蛋白质，这些蛋白质以前被人类蛋白质组组织归类为在人类蛋白质组中“缺失”。大多数N末端(77%)是内部neo-N末端(105个是新的潜在替代翻译起始点，2180个代表稳定的蛋白分解产物)，从而突出了蛋白分解过程在血小板储存过程中的突出作用。蛋白水解酶抑制剂研究表明，金属蛋白酶在贮藏过程中主要负责蛋白质的降解处理(而不是降解)。系统范围内对金属蛋白酶和其他蛋白酶底物及其各自的裂解位点的鉴定表明，在储存过程中，蛋白酶对蛋白质活性和血小板功能的影响是新的机制。所有数据集和元数据都可以通过数据集标识符为PXD000906的ProteomeXchange获得。
Proteases, and specifically metalloproteinases, have been linked to the loss of platelet function during storage before transfusion, but the underlying mechanisms remain unknown. We used a dedicated N-terminomics technique, iTRAQ terminal amine isotopic labeling of substrates (TAILS), to characterize the human platelet N-terminome, proteome, and posttranslational modifications throughout platelet storage over 9 days under blood-banking conditions. From the identified 2938 proteins and 7503 unique peptides, we characterized N-terminal methionine excision, co- and posttranslational N-alpha acetylation, protein maturation, and proteolytic processing of proteins in human platelets. We also identified for the first time 10 proteins previously classified by the Human Proteome Organization as "missing" in the human proteome. Most N termini (77%) were internal neo-N termini (105 were novel potential alternative translation start sites, and 2180 represented stable proteolytic products), thus highlighting a prominent yet previously uncharacterized role of proteolytic processing during platelet storage. Protease inhibitor studies revealed metalloproteinases as being primarily responsible for proteolytic processing (as opposed to degradation) during storage. System-wide identification of metalloproteinase and other proteinase substrates and their respective cleavage sites suggests novel mechanisms of the effect of proteases on protein activity and platelet function during storage. All data sets and metadata are available through ProteomeXchange with the data set identifier PXD000906.