What does VLA-4 do?
The integrin VLA-4 is expressed on the cell surfaces of stem cells, progenitor cells, T and B cells, monocytes, natural killer cells, eosinophils, and neutrophils. It functions to promote an inflammatory response by the immune system by assisting in the movement of leukocytes to tissue that requires inflammation.
What is the primary function of integrins?
Integrins are the principal receptors used by animal cells to bind to the extracellular matrix. They are heterodimers and function as transmembrane linkers between the extracellular matrix and the actin cytoskeleton. A cell can regulate the adhesive activity of its integrins from within.
What does VLA-4 bind to?
VLA-4 can bind to vascular cellular adhesion molecule 1 (VCAM-1). VLA-4 ligation has been shown to augment TCR-mediated T cell proliferation, presumably in a similar manner to ligation of LFA-1, by increasing the strength of the signal delivered by the TCR.
Is LFA-1 an integrin?
Among several leukocyte-specific integrins, lymphocyte function-associated antigen-1 (LFA-1 or αLβ2; CD11a/CD18) is a key T cell integrin, which plays a major role in regulating T cell activation and migration.
What does E selectin bind to?
E-selectin is inducibly expressed by cytokines (tumor necrosis factor-α and IL-1β) on inflamed endothelium, and binds to sialofucosylated glycan determinants displayed on protein and lipid scaffolds of blood cells.
What does L selectin bind?
Similar to P-selectin, L-selectin also binds to sulfatides and sulfated polysaccharides such as fucoidan and heparin. A group of O-glycosylated mucins decorated with sialic acid, termed sialomucins, represents the protein ligands for L-selectin. They are GlyCAM-1, CD34 and MAdCAM-1.
How do integrins work?
Integrins are proteins that function mechanically, by attaching the cell cytoskeleton to the extracellular matrix (ECM), and biochemically, by sensing whether adhesion has occurred. The integrin family of proteins consists of alpha and beta subtypes, which form transmembrane heterodimers.
Are integrins involved in cell migration?
Integrins are essential for cell migration and invasion, not only because they directly mediate adhesion to the extracellular matrix, but also because they regulate intracellular signalling pathways that control cytoskeletal organization, force generation and survival.
What is CR3 immunology?
Macrophage-1 antigen (hereafter complement receptor 3 or CR3) (CD11b/CD18) is a human cell surface receptor found on B and T lymphocytes, polymorphonuclear leukocytes (mostly neutrophils), NK cells, and mononuclear phagocytes like macrophages. CR3 also recognizes iC3b when bound to the surface of foreign cells.
What is ICAM in immunology?
ICAM-1 (Intercellular Adhesion Molecule 1) also known as CD54 (Cluster of Differentiation 54) is a protein that in humans is encoded by the ICAM1 gene. This gene encodes a cell surface glycoprotein which is typically expressed on endothelial cells and cells of the immune system.
Do endothelial cells express selectin?
E-Selectin (CD62E) is a 115 kDa glycoprotein, only expressed on endothelial cells after activation by interleukin 1 (IL-1), tumor necrosis factor α (TNFα) or bacterial lipopolysaccharides.
What induces production of E-selectin on endothelium?
The production of E-selectin is stimulated by the expression of P-selectin which in turn, is stimulated by tumor necrosis factor α (TNFα), interleukin-1 (IL-1) and lipopolysaccharide (LPS). It takes about two hours, after cytokine recognition, for E-selectin to be expressed on the endothelial cell’s surface.
What is the interaction between VLA-4 and VCAM-1?
The alpha4beta1 integrin VLA-4 is a leukocyte ligand for endothelial vascular cell adhesion molecule-1 (VCAM-1), fibronectin, and osteopontin. The interaction between VLA-4 at the surface of activated lymphocytes and monocytes with its ligand VCAM-1 is essential for cell migration into inflamed parenchyma.
What is the role of VLA-4 in HSCs?
VLA-4 is an integrin (α4β1) expressed on HSCs and progenitor cells and is perhaps the most intensively studied hematopoietic adhesion molecule.85 VLA-4 binds the ECM component, fibronectin, and the cell surface molecule vascular cell adhesion molecule-1 (VCAM-1 or CD106) that is constitutively expressed on stromal and endothelial cells.
How is the expression of VLA-4 regulated in T cells?
This change is achieved by talin or kindlin interacting with the parts of VLA-4 on the inside of the cell’s surface. The expression of VLA-4 in the plasma membrane is regulated by different growth factors or chemokines depending on the cell type. In T cells, IL-4 down-regulates the expression of VLA-4.
What is the function of the integrin VLA-4?
Function. The integrin VLA-4 is expressed on the cell surfaces of stem cells, progenitor cells, T and B cells, monocytes, natural killer cells, eosinophils, and neutrophils. It functions to promote an inflammatory response by the immune system by assisting in the movement of leukocytes to tissue that requires inflammation.