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CD18
In molecular biology, CD18 (Integrin beta chain-2) is an integrin beta chain protein that is encoded by the ''ITGB2'' gene in humans. Upon binding with one of a number of alpha chains, CD18 is capable of forming multiple heterodimers, which play significant roles in cellular adhesion and cell surface signaling, as well as important roles in immune responses. CD18 also exists in soluble, ligand binding forms. Deficiencies in CD18 expression can lead to adhesion defects in circulating white blood cells in humans, reducing the immune system's ability to fight off foreign invaders. Structure and function The ITGB2 protein product is CD18. Integrins are integral cell-surface proteins composed of an alpha chain and a beta chain, and are crucial for cells to be able to efficiently bind to the extracellular matrix. This is especially important for neutrophils, as cellular adhesion plays a large role in extravasation from the blood vessels. A given chain may combine with multiple partne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ITGB2
In molecular biology, CD18 (Integrin beta chain-2) is an integrin beta chain protein that is encoded by the ''ITGB2'' gene in humans. Upon binding with one of a number of alpha chains, CD18 is capable of forming multiple heterodimers, which play significant roles in cellular adhesion and cell surface signaling, as well as important roles in immune responses. CD18 also exists in soluble, ligand binding forms. Deficiencies in CD18 expression can lead to adhesion defects in circulating white blood cells in humans, reducing the immune system's ability to fight off foreign invaders. Structure and function The ITGB2 protein product is CD18. Integrins are integral cell-surface proteins composed of an alpha chain and a beta chain, and are crucial for cells to be able to efficiently bind to the extracellular matrix. This is especially important for neutrophils, as cellular adhesion plays a large role in extravasation from the blood vessels. A given chain may combine with multiple partner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ICAM-1
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. It binds to integrins of type CD11a / CD18, or Integrin alpha M, CD11b / CD18 and is also exploited by rhinovirus as a receptor for entry into respiratory epithelium. Structure ICAM-1 is a member of the immunoglobulin superfamily, the superfamily of proteins including antibody, antibodies and T cell receptor, T-cell receptors. ICAM-1 is a transmembrane protein possessing an N-terminus, amino-terminus extracellular domain, a single transmembrane domain, and a C-terminus, carboxy-terminus cytoplasmic domain. The structure of ICAM-1 is characterized by heavy glycosylation, and the protein’s extracellular domain is composed of multiple loops created by disulfide bridges within the protein. The dominan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leukocyte Adhesion Deficiency
Leukocyte adhesion deficiency (LAD) is a rare autosomal recessive disorder characterized by immunodeficiency resulting in recurrent infections. LAD is currently divided into three subtypes: LAD1, LAD2, and the recently described LAD3, also known as LAD-1/variant. In LAD3, the immune defects are supplemented by a Glanzmann thrombasthenia-like bleeding tendency. Signs and symptoms LAD was first recognized as a distinct clinical entity in the 1970s. The classic descriptions of LAD included recurrent bacterial infections, defects in neutrophil adhesion, and a delay in umbilical cord sloughing. The adhesion defects result in poor leukocyte chemotaxis, particularly neutrophil, inability to form pus and neutrophilia. Individuals with LAD suffer from bacterial infections beginning in the neonatal period. Infections such as omphalitis, pneumonia, gingivitis, and peritonitis are common and often life-threatening due to the infant's inability to properly destroy the invading pathogens. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leukocyte Adhesion Deficiency
Leukocyte adhesion deficiency (LAD) is a rare autosomal recessive disorder characterized by immunodeficiency resulting in recurrent infections. LAD is currently divided into three subtypes: LAD1, LAD2, and the recently described LAD3, also known as LAD-1/variant. In LAD3, the immune defects are supplemented by a Glanzmann thrombasthenia-like bleeding tendency. Signs and symptoms LAD was first recognized as a distinct clinical entity in the 1970s. The classic descriptions of LAD included recurrent bacterial infections, defects in neutrophil adhesion, and a delay in umbilical cord sloughing. The adhesion defects result in poor leukocyte chemotaxis, particularly neutrophil, inability to form pus and neutrophilia. Individuals with LAD suffer from bacterial infections beginning in the neonatal period. Infections such as omphalitis, pneumonia, gingivitis, and peritonitis are common and often life-threatening due to the infant's inability to properly destroy the invading pathogens. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrophage-1 Antigen
Macrophage-1 antigen (or integrin αMβ2 or macrophage integrin or Mac-1) is a complement receptor ("CR3") consisting of CD11b (integrin αM) and CD18 (integrin β2). The integrin α chain is noncovalently bound to the integrin β chain. It binds to iC3b and can be involved in cellular adhesion, binding to the intercellular adhesion molecule-1 (ICAM-1). CR3 causes phagocytosis and destruction of cells opsonized with iC3b. CR3 and CR4 are thought to exhibit overlapping functions; however, the distinct binding sites to iC3b suggests differences in their functions. Additionally, CR3 has been shown to have therapeutic promise. Function 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 is a pattern recognition receptor, capable of recognizing and binding to many molecules found on the surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD11a
Integrin, alpha L (antigen CD11A (p180), lymphocyte function-associated antigen 1; alpha polypeptide), also known as ITGAL, is a protein that in human is encoded by ''ITGAL'' gene. CD11a functions in the immune system. It is involved in cellular adhesion and costimulatory signaling. It is the target of the drug efalizumab. Function ''ITGAL'' gene encodes the integrin alpha L chain. Integrins are heterodimeric integral membrane proteins composed of an alpha chain and a beta chain. This I-domain containing alpha integrin combines with the beta 2 chain (ITGB2) to form the integrin lymphocyte function-associated antigen-1 (LFA-1), which is expressed on all leukocytes. LFA-1 plays a central role in leukocyte intercellular adhesion through interactions with its ligands, ICAMs 1-3 (intercellular adhesion molecules 1 through 3), and also functions in lymphocyte costimulatory signaling. CD11a is one of the two components, along with CD18, which form lymphocyte function-associated antig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD11b
Integrin alpha M (ITGAM) is one protein subunit that forms heterodimeric integrin alpha-M beta-2 (αMβ2) molecule, also known as ''macrophage-1 antigen'' (Mac-1) or ''complement receptor 3'' (CR3). ITGAM is also known as CR3A, and cluster of differentiation molecule 11B (CD11B). The second chain of αMβ2 is the common integrin β2 subunit known as CD18, and integrin αMβ2 thus belongs to the β2 subfamily (or leukocyte) integrins. αMβ2 is expressed on the surface of many leukocytes involved in the innate immune system, including monocytes, granulocytes, macrophages, and natural killer cells. It mediates inflammation by regulating leukocyte adhesion and migration and has been implicated in several immune processes such as phagocytosis, cell-mediated cytotoxicity, chemotaxis and cellular activation. It is involved in the complement system due to its capacity to bind inactivated complement component 3b (iC3b). The ITGAM (alpha) subunit of integrin αMβ2 is directly invol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD11c
CD11c, also known as Integrin, alpha X (complement component 3 receptor 4 subunit) (ITGAX), is a gene that encodes for CD11c . CD11c is an integrin alpha X chain protein. Integrins are heterodimeric integral membrane proteins composed of an alpha chain and a beta chain. This protein combines with the beta 2 chain (ITGB2) to form a leukocyte-specific integrin referred to as inactivated-C3b (iC3b) receptor 4 (CR4). The alpha X beta 2 complex seems to overlap the properties of the alpha M beta 2 integrin in the adherence of neutrophils and monocytes to stimulated endothelium cells, and in the phagocytosis of complement coated particles. CD11c is a type I transmembrane protein found at high levels on most human dendritic cells, but also on monocytes, macrophages, neutrophils, and some B cells that induces cellular activation and helps trigger neutrophil respiratory burst; expressed in hairy cell leukemias, acute nonlymphocytic leukemias, and some B-cell chronic lymphocytic leukemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LFA-1
Lymphocyte function-associated antigen 1 (LFA-1) is an integrin found on lymphocytes and other leukocytes. LFA-1 plays a key role in emigration, which is the process by which leukocytes leave the bloodstream to enter the tissues. LFA-1 also mediates firm arrest of leukocytes. Additionally, LFA-1 is involved in the process of cytotoxic T cell mediated killing as well as antibody mediated killing by granulocytes and monocytes. As of 2007, LFA-1 has 6 known ligands: ICAM-1, ICAM-2, ICAM-3, ICAM-4, ICAM-5, and JAM-A. LFA-1/ICAM-1 interactions have recently been shown to stimulate signaling pathways that influence T cell differentiation. LFA-1 belongs to the integrin superfamily of adhesion molecules. Structure LFA-1 is a heterodimeric glycoprotein with non-covalently linked subunits. LFA-1 has two subunits designated as the alpha subunit and beta subunit. The alpha subunit was named aL in 1983. The alpha subunit is designated CD11a; and the beta subunit, unique to leukocytes, is bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complement Receptors
A complement receptor is a membrane-bound receptor belonging to the complement system, which is part of the innate immune system. Complement receptors bind effector protein fragments that are produced in response to antigen-antibody complexes or damage-associated molecules. Complement receptor activation contributes to the regulation of inflammation, leukocyte extravasation, and phagocytosis; it also contributes to the adaptive immune response. Different complement receptors can participate in either the classical complement pathway, the alternative complement pathway, or both. Expression and function White blood cells, particularly monocytes and macrophages, express complement receptors on their surface. All four complement receptors can bind to fragments of complement component 3 or complement component 4 coated on pathogen surface, but the receptors trigger different downstream activities. Complement receptor (CR) 1, 3, and 4 function as opsonins which stimulate phagocytosis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integrin
Integrins are transmembrane receptors that facilitate cell-cell and cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle, organization of the intracellular cytoskeleton, and movement of new receptors to the cell membrane. The presence of integrins allows rapid and flexible responses to events at the cell surface (''e.g''. signal platelets to initiate an interaction with coagulation factors). Several types of integrins exist, and one cell generally has multiple different types on its surface. Integrins are found in all animals while integrin-like receptors are found in plant cells. Integrins work alongside other proteins such as cadherins, the immunoglobulin superfamily cell adhesion molecules, selectins and syndecans, to mediate cell–cell and cell–matrix interaction. Ligands for integrins include fibronectin, vitronectin, collagen and laminin. Stru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GNB2L1
Receptor for activated C kinase 1 (RACK1), also known as guanine nucleotide-binding protein subunit beta-2-like 1 (GNB2L1), is a 35 kDa protein that in humans is encoded by the RACK1 gene. Function RACK1 was originally isolated and identified as an intracellular protein receptor for protein kinase C, noting the significant homology to the beta subunit of heterotrimeric G proteins. Later studies established RACK1, and its yeast homolog Asc1, as a core ribosomal protein of the eukaryotic small (40S) ribosomal subunit. Much of the function of Asc1/RACK1 appears to result from its position on the 'head' of the 40S ribosomal subunit. Asc1/RACK1 participates in several aspects of eukaryotic translation and ribosome quality control, including IRES-mediated translation, non-stop decay, non-functional 18S ribosomal RNA decay, and frameshifting. Interactions RACK1 is positioned at the solvent-exposed surface of the 40S ribosomal subunit, where it is held in place through contact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |