Complement receptor type 1 (CR1) also known as C3b/C4b receptor or CD35 (cluster of differentiation 35) is a protein that in humans is encoded by the CR1gene.
This gene is a member of the regulators of complement activation (RCA) family and is located in the 'cluster RCA' region of chromosome 1. The gene encodes a monomeric single-pass type I membrane glycoprotein found on erythrocytes, leukocytes, glomerular podocytes, hyalocytes, and splenic follicular dendritic cells. The Knops blood group system is a system of antigens located on this protein. The protein mediates cellular binding to particles and immune complexes that have activated complement. Decreases in expression of this protein and/or mutations in its gene have been associated with gallbladder carcinomas, mesangiocapillary glomerulonephritis, systemic lupus erythematosus and sarcoidosis. Mutations in this gene have also been associated with a reduction in Plasmodium falciparum rosetting, conferring protection against severe malaria. Alternate allele-specific splice variants, encoding different isoforms, have been characterized. Additional allele specific isoforms, including a secreted form, have been described but have not been fully characterized.
A complement receptor is a receptor of the complement system, a part of the mediated innate immune system. Complement receptors are responsible for detecting pathogens by mechanisms not mediated by antibodies. Complement activity is not antigen sensitive, but can be triggered by specific antigens. Therefore, complement (a group of proteins in the serum that help achieve phagocytosis and lysis of antigens) is also part of the humoral immune system.
Complement receptors
Types include:
Clinical significance
Defects in these receptors can be associated with disease.
Complement receptor type 2 (CR2), also known as complement C3d receptor, Epstein-Barr virus receptor, and CD21 (cluster of differentiation 21), is a protein that in humans is encoded by the CR2 gene.
CR2 is involved in the complement system. It binds to iC3b (inactive derivative of C3b), C3dg, or C3d.B cells have CR2 receptors on their surfaces, allowing the complement system to play a role in B-cell activation and maturation
Interactions
CR2 on mature B cells form a complex with two other membrane proteins, CD19 and CD81(=TAPA-1). The CR2-CD19-CD81 complex is often called the B cell coreceptor complex, because CR2 binds to antigens through attached C3d (or iC3b or C3dg) when the membrane IgM binds to the antigen. This results in the B cell having greatly enhanced response to the antigen.
Complement receptor 2 has been shown to interact with CD19.
Epstein-Barr virus (EBV) binds to B cells at CR2 during infection of these cells. Yefenof et al. (1976) found complete overlapping of EBV receptors and C3 receptors on human B cells.
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).
Complement receptor 3 (CR3)(CD11b/CD18) is a human cell surface receptor found on 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 surfaces of invading bacteria. CR3 also recognizes iC3b when bound to the surface of foreign cells. Binding to the receptor causes phagocytosis and destruction of the foreign cell.
CR3 belongs to a family of cell surface receptors known as integrins (because they share this particular β chain, they are referred to as β2-integrins), which are extremely widely distributed throughout nature and which generally are important in cellular adhesion and cell-cell interactions in a variety of cells and circumstances.
Fab functions tested include antigen-binding capacities, and Fc functions tested include complement activation and Fc-receptor-mediated leukocyte activation ... on the endogenous neonatal Fc receptor.
As aHUS patients often face critical health complications due to complement system dysregulation, there is a pressing demand for advanced therapies that can effectively manage symptoms and improve patient outcomes.
MDG1, Prime Standard), an oncology platform company focused on the research and development of T cell receptor ... This complements previously granted patents from the European and JapanPatent Offices.
... of myelin by macrophages via the recognition of immunoglobulin (Ig) fragment crystallizable receptor (FcR), leading to the activation of the complement cascade and resulting axonal damage.
Athletes with 5-ARD and PAIS have an XY chromosomal complement; they have testes; their testes produce testosterone well outside of the normal female range; their androgen receptors read and process ...
Q32 Bio's lead programs, focused on the IL-7 / TSLP receptor pathways and complement system, address immune dysregulation to help patients take back control of their lives. .
Q32 Bio's lead programs, focused on the IL-7 / TSLP receptor pathways and complement system, address immune dysregulation to help patients take back control of their lives ... complement therapeutics.
Narcan and the compound 368 were found to bind at different sites of the opioid receptor, enabling them to complement each other in blocking opioids like fentanyl ...O'Brien et al, A µ-opioid receptor ...
Complement 3 Glomerulopathy Drugs under development based on the stage of development, route of administration, target receptor, monotherapy or combination therapy, a different mechanism of action, and molecular type.
ComplementFunction/Activity Testing ...Scientists primarily verify or screen complement inhibitors through hemolysis inhibition assays, high-throughput screening based on cell imaging, receptor-ligand binding assays, and other approaches.
The study identifies specific receptors in the human body that these ...Genetic data, including Mendelian randomization, complemented these predictions by assessing causality and receptor involvement.
A human odorant receptor for this compound, however, was previously unknown ... Moreover, it complements the spectrum of another odorant receptor that recognizes a very broad range of food-relevant odorants," reports first author FranziskaHaag.
A new study demonstrates the potential of Serum Detect's T-cell receptor (TCR) repertoire liquid biopsy to complement circulating tumor DNA approaches ... .
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While we concentrate on the late-stage development of C21 in IPF, we are concurrently reviewing opportunities for follow-on indications and AT2 receptor agonists to complement this progress.
Citizen Tribune
09 Jul 2024
Citizen Tribune
09 Jul 2024