What causes leukocyte adhesion to endothelial cells?

What causes leukocyte adhesion to endothelial cells?

Lectin-like adhesion glycoproteins, called the selectins, mediate leukocyte rolling, while the firm adhesion and subsequent transendothelial migration of leukocytes are mediated by the interaction of integrins (CD11/CD18, VLA-4) on leukocytes with immunoglobulin-like adhesion molecules on ECs (e.g., ICAM-1, VCAM-1).

What does P-selectin bind to?

The primary ligand for P-selectin is P-selectin glycoprotein ligand-1 (PSGL-1) which is expressed on almost all leukocytes, although P-selectin also binds to heparan sulfate and fucoidans.

What does N Cam bind to?

Neural cell adhesion molecule (NCAM), also called CD56, is a homophilic binding glycoprotein expressed on the surface of neurons, glia and skeletal muscle. NCAM has been implicated as having a role in cell–cell adhesion, neurite outgrowth, synaptic plasticity, and learning and memory.

What is the trigger that begins the process of a leukocyte binding to an endothelial cell?

Molecules other than chemokines can trigger leukocyte adhesion. Platelet activating factor (PAF) on the endothelial surface via its receptor on leukocytes (Zimmerman et al, 1990) as well as cross-linking L-selectin on leukocytes (Simon et al, 1995) can trigger inside-out integrin activation.

What are leukocyte integrins?

Beta2-integrins are complex leukocyte-specific adhesion molecules that are essential for leukocyte (e.g., neutrophil, lymphocyte) trafficking, as well as for other immunological processes such as neutrophil phagocytosis and ROS production, and T cell activation.

Do platelets activate thrombin?

Platelet activation by thrombin is relevant to arterial thrombosis, therefore it is an attractive target for the development of new antithrombotic drugs. On human platelets PAR1 and, later PAR4, were demonstrated to mediate most of the platelet responses to thrombin.

How are leukocytes transported?

Leukocytes pass through spaces between blood vessel cells and the process from attachment to transport across the wall of the blood vessels is called diapedesis. Diapedesis is followed by movement of leukocytes toward the areas of infection marked by high concentration of inflammatory proteins.

What activates integrins on leukocytes?

Leukocytes are activated by selectins and chemokines on the surface of activated endothelial cells close to a site of inflammation. This slows down the leukocyte speed and induces integrins to change their conformation through inside-out signaling, allowing them to bind ICAMs on the endothelium.

What is the structure of a proteoglycan?

Proteoglycans are glycosylated proteins which have covalently attached highly anionic glycosaminoglycans. Many forms of proteoglycans are present in virtually all extracellular matrices of connective tissues.

What are proteoglycans in the extracellular matrix?

Function of proteoglycans in the extracellular matrix Proteoglycans are glycosylated proteins which have covalently attached highly anionic glycosaminoglycans. Many forms of proteoglycans are present in virtually all extracellular matrices of connective tissues.

What is the function of glycoproteins in the cell membrane?

Glycoproteins act as integral membrane proteins, and play a role in cell-cell recognition and signaling. Proteoglycans provide structural support and mechanical strength to the ECM, play a role in the modulation of cell growth processes, and provide padding in joints. Examples. Thrombospondin.

Why are proteoglycans important to cartilage?

The water associated with proteoglycans provides the cushion function of cartilage. The inability to sufficiently break down proteoglycans is linked to several genetic disorders and leads to other disease symptoms. Carbohydrate modifications are essential to proper functioning of proteins.

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