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CD31 (cluster of differentiation 31) is a transmembrane protein encoded by the PECAM1 (platelet endothelial cell adhesion molecule) gene. CD31 has essential roles in platelet biology, signal transduction, as well as leukocyte and endothelial cell biology.1
CD31 is a transmembrane protein 3, 7 that requires special treatment of samples in western blot. It contains many post-translational modifications, including glycosylations and phosphorylations 2, 7, 9,10,11,12,
Positive: HUVEC and Jurkat cell lysates (ab7899); Human spleen and kidney tissue lysate.
Negative: NIH/3T3 whole cell lysate (ab7179)
Immunostaining CD31 can be used to help identify blood vessels and endothelial cells, where this protein tends to be most concentrated. Pathologists use it to identify vascular origin of tumors, although nodal sinuses may also show a signal 13. CD31 is also used to identify vascular invasion 14, 15 and assess the micro-vessel density of tumors 16.
Positive: Human tonsil tissue
CD31 can be used as a biomarker for endothelial cells. It is widely used to confirm the cell type and co-localization of proteins of interest in immunocytochemistry.
Positive: HUVEC cells
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