Characterizing the O-glycosylation landscape of human plasma, platelets, and endothelial cells
The hemostatic system comprises platelet aggregation, coagulation, and fibrinolysis, and is critical to the maintenance of vascular integrity. Multiple studies indicate that glycans play important roles in the hemostatic system; however, most investigations have focused on N-glycans because of the c...
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Published in | Blood advances Vol. 1; no. 7; pp. 429 - 442 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Elsevier Inc
28.02.2017
American Society of Hematology Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | The hemostatic system comprises platelet aggregation, coagulation, and fibrinolysis, and is critical to the maintenance of vascular integrity. Multiple studies indicate that glycans play important roles in the hemostatic system; however, most investigations have focused on N-glycans because of the complexity of O-glycan analysis. Here we performed the first systematic analysis of native-O-glycosylation using lectin affinity chromatography coupled to liquid chromatography mass spectrometry (LC-MS)/MS to determine the precise location of O-glycans in human plasma, platelets, and endothelial cells, which coordinately regulate hemostasis. We identified the hitherto largest O-glycoproteome from native tissue with a total of 649 glycoproteins and 1123 nonambiguous O-glycosites, demonstrating that O-glycosylation is a ubiquitous modification of extracellular proteins. Investigation of the general properties of O-glycosylation established that it is a heterogeneous modification, frequently occurring at low density within disordered regions in a cell-dependent manner. Using an unbiased screen to identify associations between O-glycosites and protein annotations we found that O-glycans were over-represented close (± 15 amino acids) to tandem repeat regions, protease cleavage sites, within propeptides, and located on a select group of protein domains. The importance of O-glycosites in proximity to proteolytic cleavage sites was further supported by in vitro peptide assays demonstrating that proteolysis of key hemostatic proteins can be inhibited by the presence of O-glycans. Collectively, these data illustrate the global properties of native O-glycosylation and provide the requisite roadmap for future biomarker and structure-function studies.
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•Human platelets, endothelial cells, and plasma proteins are extensively O-glycosylated, with >1123 O-glycosites identified in this study.•O-glycosites can be classified into functional subgroups; one important function includes the protection from proteolytic processing. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2473-9529 2473-9537 |
DOI: | 10.1182/bloodadvances.2016002121 |