Tumour necrosis factor alpha

1A8M, 1TNF, 2AZ5, 2E7A, 2TUN, 2ZJC, 2ZPX, 3ALQ, 3IT8, 3L9J, 3WD5, 4G3Y, 4TSV, 4TWT, 5TSW712421926ENSG00000232810ENSG00000228849ENSG00000206439ENSMUSG00000024401P01375P06804NM_000594NM_001278601NM_013693NP_000585NP_001265530NP_038721Tumor necrosis factor (TNF, tumor necrosis factor alpha, TNFα, cachexin, or cachectin) is a cell signaling protein (cytokine) involved in systemic inflammation and is one of the cytokines that make up the acute phase reaction. It is produced chiefly by activated macrophages, although it can be produced by many other cell types such as CD4+ lymphocytes, NK cells, neutrophils, mast cells, eosinophils, and neurons. TNFα is a member of the TNF superfamily, consisting of various transmembrane proteins with a homologous TNF domain. 1a8m: TUMOR NECROSIS FACTOR ALPHA, R31D MUTANT1tnf: THE STRUCTURE OF TUMOR NECROSIS FACTOR-ALPHA AT 2.6 ANGSTROMS RESOLUTION. IMPLICATIONS FOR RECEPTOR BINDING2az5: Crystal Structure of TNF-alpha with a small molecule inhibitor2tun: CONFORMATIONAL CHANGES IN THE (ALA-84-VAL) MUTANT OF TUMOR NECROSIS FACTOR4tsv: HIGH RESOLUTION CRYSTAL STRUCTURE OF A HUMAN TNF-ALPHA MUTANT5tsw: HIGH RESOLUTION CRYSTAL STRUCTURE OF A HUMAN TNF-ALPHA MUTANT Tumor necrosis factor (TNF, tumor necrosis factor alpha, TNFα, cachexin, or cachectin) is a cell signaling protein (cytokine) involved in systemic inflammation and is one of the cytokines that make up the acute phase reaction. It is produced chiefly by activated macrophages, although it can be produced by many other cell types such as CD4+ lymphocytes, NK cells, neutrophils, mast cells, eosinophils, and neurons. TNFα is a member of the TNF superfamily, consisting of various transmembrane proteins with a homologous TNF domain. The primary role of TNF is in the regulation of immune cells. TNF, being an endogenous pyrogen, is able to induce fever, apoptotic cell death, cachexia, inflammation and to inhibit tumorigenesis and viral replication and respond to sepsis via IL1 & IL6 producing cells. Dysregulation of TNF production has been implicated in a variety of human diseases including Alzheimer's disease, cancer, major depression, psoriasis and inflammatory bowel disease (IBD). Though controversial, studies of depression and IBD are currently being linked to increased levels of TNFα. Recombinant TNF is used as an immunostimulant under the INN tasonermin. TNF can be produced ectopically in the setting of malignancy and parallels parathyroid hormone both in causing secondary hypercalcemia and in the cancers with which excessive production is associated. The theory of an anti-tumoral response of the immune system in vivo was recognized by the physician William B. Coley. In 1968, Gale A Granger from the University of California, Irvine, reported a cytotoxic factor produced by lymphocytes and named it lymphotoxin (LT). Credit for this discovery is shared by Nancy H. Ruddle from Yale University, who reported the same activity in a series of back-to-back articles published in the same month. Subsequently, in 1975 Lloyd J. Old from Memorial Sloan-Kettering Cancer Center, New York, reported another cytotoxic factor produced by macrophages and named it tumor necrosis factor (TNF). Both factors were described based on their ability to kill mouse fibrosarcoma L-929 cells. These concepts were extended to systemic disease in 1981, when Ian A. Clark, from the Australian National University, in collaboration with Elizabeth Carswell in Old's group, working with pre-sequencing era data, reasoned that excessive production of TNF causes malaria disease and endotoxin poisoning. The cDNAs encoding LT and TNF were cloned in 1984 and were revealed to be similar. The binding of TNF to its receptor and its displacement by LT confirmed the functional homology between the two factors. The sequential and functional homology of TNF and LT led to the renaming of TNF as TNFα (this article) and LT as TNFβ. In 1985, Bruce A. Beutler and Anthony Cerami discovered that cachectin (a hormone which induces cachexia) was actually TNF. They then identified TNF as a mediator of lethal endotoxin poisoning. Kevin J. Tracey and Cerami discovered the key mediator role of TNF in lethal septic shock, and identified the therapeutic effects of monoclonal anti-TNF antibodies.More recently, research in the Laboratory of Mark Mattson has shown that TNF can prevent the death/apoptosis of neurons by a mechanism involving activation of the transcription factor NF-kappaB which induces the expression of Mn-SOD and Bcl-2. The human TNF gene (TNFA) was cloned in 1985. It maps to chromosome 6p21.3, spans about 3 kilobases and contains 4 exons. The last exon shares similarity with lymphotoxin alpha (LTA, known also as TNF-β). The 3' UTR of TNFα contains an AU-rich element (ARE). TNF is primarily produced as a 233-amino acid-long type II transmembrane protein arranged in stable homotrimers. From this membrane-integrated form the soluble homotrimeric cytokine (sTNF) is released via proteolytic cleavage by the metalloprotease TNF alpha converting enzyme (TACE, also called ADAM17). The soluble 51 kDa trimeric sTNF tends to dissociate at concentrations below the nanomolar range, thereby losing its bioactivity. The secreted form of human TNFα takes on a triangular pyramid shape, and weighs around 17-kDa. Both the secreted and the membrane bound forms are biologically active, although the specific functions of each is controversial. But, both forms do have overlapping and distinct biological activities. The common house mouse TNFα and human TNF are structurally different. The 17-kilodalton (kDa) TNF protomers (185-amino acid-long) are composed of two antiparallel β-pleated sheets with antiparallel β-strands, forming a 'jelly roll' β-structure, typical for the TNF family, but also found in viral capsid proteins. TNF can bind two receptors, TNFR1 (TNF receptor type 1; CD120a; p55/60) and TNFR2 (TNF receptor type 2; CD120b; p75/80). TNFR1 is 55-kDa and TNFR2 is 75-kDa. TNFR1 is expressed in most tissues, and can be fully activated by both the membrane-bound and soluble trimeric forms of TNF, whereas TNFR2 is found typically in cells of the immune system, and respond to the membrane-bound form of the TNF homotrimer. As most information regarding TNF signaling is derived from TNFR1, the role of TNFR2 is likely underestimated. Upon contact with their ligand, TNF receptors also form trimers, their tips fitting into the grooves formed between TNF monomers. This binding causes a conformational change to occur in the receptor, leading to the dissociation of the inhibitory protein SODD from the intracellular death domain. This dissociation enables the adaptor protein TRADD to bind to the death domain, serving as a platform for subsequent protein binding. Following TRADD binding, three pathways can be initiated.