What is the function of selectins?
The selectins are cell surface lectins that have evolved to mediate the adhesion of white blood cells to endothelial cells and platelets under flow. They recognize fucosylated, sialylated and in some cases sulfated ligands expressed on scaffold glycoproteins serving as functional counter-receptors.
What do selectins recognize?
Selectins recognize carbohydrate structures such as sialyl-Lewis x, sialyl-Lewis a, or sialyl 6-sulfo Lewis x as ligands.
What is the role of selectins in inflammation?
During inflammation, selectins enable the initial attachment of leukocytes from the bloodstream, which causes their downstream movement along the endothelium via adhesive interactions referred to as leukocyte rolling.
How many types of selectins are there?
three
There are three subsets of selectins: E-selectin (in endothelial cells) L-selectin (in leukocytes) P-selectin (in platelets and endothelial cells)
How are selectins activated?
The selectin ligand PSGL-1 redistributes to the uropod and captures activated platelets by interacting with P-selectin. Platelet–neutrophil interactions transduce signals that facilitate intraluminal crawling.
Where are selectins found?
Selectins are carbohydrate-binding molecules that bind to fucosylated and sialylated glycoprotein ligands, and are found on endothelial cells, leukocytes and platelets. They are involved in trafficking of cells of the innate immune system, T lymphocytes and platelets.
What is the difference between selectins and integrins?
Selectins and some of their counter-receptors function also as signal-transducing receptors, significantly contributing to leukocyte and endothelial cell activation. Integrins represent a large family of adhesion receptors that are widely expressed and mainly interact with extracellular matrix components.
Where do selectins bind?
The selectins bind to carbohydrate structures on glycoproteins, glycolipids, and proteoglycans. Glycoproteins are the most likely candidates for physiologically relevant ligands. Only a few glycoproteins are appropriately glycosylated to allow strong binding to the selectins.
Are selectins intracellular?
Selectins are transmembrane proteins with a long extracellular domain (that binds to carbohydrate moiety of their ligands), a transmembrane domain, and a short intracellular domain (binds to cytoskeleton).
Are selectins and integrins adhesion molecules?
Cadherins, selectins, and integrins are well-known cell adhesion molecules that allow binding to neighboring cells, ECM proteins, and soluble factors.
What is the difference between integrins and selectins?
What are the different types of selectins?
There are three members of selectins (named on the basis of cellular expression), P-selectin, E-selectin, and L-selectin localized on the surface of platelets, endothelial cells, and leukocytes, respectively ( Table 7–1 ). The exception is that P-selectin is also expressed in activated endothelial cells.
What are the components of the selectin family?
The selectin family includes three related molecules (L-selectin on leukocytes, E selectin on endothelial cells, and P-selectin on activated platelets and endothelial cells). Selectins share a common structure of two or more complement regulatory domains, an epidermal growth factor–like domain, and a lectin domain.
What is the difference between E selectin and P selectin?
Selectins are a family of three closely related glycoproteins (P-selectin expressed on platelets and leukocytes, E-selectin expressed on endothelial cells, and L-selectin expressed on leukocytes, monocytes, neutrophils, and eosinophils).
What is the function of L-selectin?
Selectins Selectins are cell surface lectins that have evolved to mediate the adhesion of leukocytes to endothelial cells and platelets under flow. Three selectins have been identified: L-selectin (leukocyte selectin), P-selectin (platelet selectin), and E-selectin (endothelial selectin).
