| 背景介绍： |
This protein is a cell adhesion molecule expressed on platelets and at endothelialcell intercellular junctions. Type I membrane protein. SIZE: 738 amino acids;82536 Da. SUBCELLULAR LOCATION: Membrane; Single-pass type Imembrane protein. TISSUE SPECIFICITY: Long isoform predominates alltissues examined, isoform Delta12 was detected only in trachea and isoformDelta14-15 only in lung, isoform Delta14 was detected in all tissues examinedwith the strongest expression in heart. PTM: Phosphorylated on Ser and Tyrresidues after cellular activation. SIMILARITY: Contains 6 Ig-like C2-type(immunoglobulin-like) domains.CD31, also known as platelet endothelial celladhesion molecule 1 (PECAM1), is a type I integral membrane glycoprotein anda member of the immunoglobulin superfamily of cell surface receptors. It is foundon the surface of platelets, monocytes, neutrophils, and some types of T-cells, andmakes up a large portion of endothelial cell intercellular junctions. CD31 isimplicated in several functions, including transendothelial migration of leukocytes,angiogenesis, and integrin activation. Tyr-690 plays a critical role in leukocytetransendothelial migration (TEM) and is required for efficient trafficking of CD31to and from the lateral border recycling compartment (LBRC) and is also essentialfor the LBRC membrane to be targeted around migrating leukocytes. CD31prevents phagocyte ingestion of closely apposed viable cells by transmitting'detachment' signals, and changes function on apoptosis, promoting tethering ofdying cells to phagocytes (the encounter of a viable cell with a phagocyte via thehomophilic interaction of CD31 on both cell surfaces leads to the viable cell'sactive repulsion from the phagocyte. During apoptosis, the inside-out signaling ofCD31 is somehow disabled so that the apoptotic cell does not actively reject thephagocyte anymore. The lack of this repulsion signal together with the interactionof the eat-me signals and their respective receptors causes the attachment of theapoptotic cell to the phagocyte, thus triggering the process of engulfment). CD31has been used to measure angiogenesis in association with tumor recurrence.Other studies have also indicated that CD31 and CD34 can be used as markersfor myeloid progenitor cells and recognize different subsets of myeloid leukemiainfiltrates (granular sarcomas). |
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