Tumor necrosis factor receptor superfamily member 12A also known as the TWEAK receptor (TWEAKR) is a protein that in humans is encoded by the TNFRSF12A gene. [5] [6] [7]
Other names used when talking about TNFRSF12A are fibroblast growth factor-inducible immediate-early response protein 14 (FN14). [8] TNFRSF12A is a unique member of the Tumor Necrosis Factor Receptor superfamily. TNFRSF12A is the smallest member of the Tumor Necrosis Factor Receptor superfamily [8] and the gene expression is highly regulated in a live organism and a petri dish. [9] TNFRSF12A is the receptor for the TWEAK which is its ligand. [8] Many other members of the Tumor necrosis factor superfamily can bind to other ligands but this receptor can only bind to TNFRSF12. [10] TNFRSF12A is found in many human tissues, including the heart, placenta, lung, skeletal muscle, kidney, and pancreas. It is involved in several biological processes, such as inflammatory reactions, angiogenesis, cell proliferation, and cell death. [11]
This receptor can be found in chromosome 16 in humans [12] and chromosome 17 in mice. [6] The TNFRSF12A receptors in mice and humans are 93 percent similar. [11] This receptor is made of one hundred and twenty-eight amino acids and one cysteine-rich domain [13] then once fully developed the amino acids drop to one hundred and two amino acids. This receptor is a type I transmembrane protein because of the disulfide bonds that form the cysteine-rich domains without a death domain. [14] Although the receptor does not have a death domain it can still produce a weak death cell signal. [8] The receptor is made of helices, the β-sheet, and the loop regions, and disulfide bonds for CRD. [13] For further context, the CRD's tertiary structure consists of a beta-sheet with two strands, followed by a 3(10) helix and a C-terminal alpha-helix, and is held together by three disulfide bonds that connect Cys36-Cys49, Cys52-Cys67, and Cys55-Cys64. [13] When the disulfide bond connectivities and tertiary structures of the Fn14 CRD were compared to those of other CRDs, it was discovered that it is similar to the fourth CRD of TNF receptor 1 (A1-C2 module type), but not to the CRD of B-cell maturation antigen and the second CRD of transmembrane activator and CAML (calcium modulator and cyclophilin ligand) interactor (A1-D2). [13] The cysteine-rich domain is made of 53 amino acid residues which are outside the call of the ligand binding region. [13]
In 1997 the discovery of the ligand TNFRSF12 [15] led to the discovery of the receptor TNFRSF12A in 1999. [8] The receptor was found in chromosome 17 inside the T-locus on a mouse while doing research about polypeptide growth factors. [6] When they were trying to identify on fibroblast growth factors (FGF) they discovered fibroblast growth factor-inducible immediate-early response protein, FN14, and did not know what protein had similar structures as it as well. [6] When it was discovered they decided to name it FN14 because the projected molecular mass of about 10.8 kilodaltons. [6] Gene expression was also found in many of the major organs of newborn animals, and in the adult heart, kidney, lung, ovary, and skin. [6] This led to the possibility of FN14 being a ligand binding site and more research on this receptor. [6] It was determined that 93 percent of the structure was made of amino acids when comparing the receptor structure of human or mouse form. [11]
Tumor necrosis factors are important regulators of many different cells and tissues which makes TNFRSF12A important for expressing many different cells and tissues. TNFRSF12A is expressed in many different cells and tissues due to the function of TNFRSF12. [9] What makes TNFRSF12A stand out other than its size from the other Tumor necrosis factors receptor superfamily is that the gene expression is extremely regulated in a live organism and in a petri dish. [9] [8] There was a recent study done in 2023 about how FN14 signaling contributes to the growth and duplication of tumors (angiogenesis). [11] [8] Increased expressions or interactions of TNFRSF12A and TNFRSF12 have been found to correlate with diseases and morbidity such as acute ischemic stroke, Rheumatoid Arthritis, Systemic Lymphocytic Erythematosus (SLE), Multiple Sclerosis and Cancer. [9] [16] [8] [11] In a clinical study, the overall severity of the disease was found to be reduced by intraperitoneal injection of an anti-TWEAK neutralizing monoclonal antibody in rats and mice. [8] The result of the clinical study implied that Fn14 was a tumor biomarker and that it should be taken into account as a potential new cancer treatment target. [8] This leads to the possibility of blocking the ligand from binding to the receptor to stop the expression of TRNRSF12A to reduce or even stop the gene expression. There are other current clinical studies on how TNFRSF12A is expressed and affects different cell types. Studies have shown that high expression levels can lead to worse outcomes. [11]
TNFRSF12A has been shown to interact with TNFRSF12 and TNFR-associated factor (TRAF) 1, 2, 3 and 5. [17] [18]
In the field of cell biology, TNF-related apoptosis-inducing ligand (TRAIL), is a protein functioning as a ligand that induces the process of cell death called apoptosis.
Lymphotoxin is a member of the tumor necrosis factor (TNF) superfamily of cytokines, whose members are responsible for regulating the growth and function of lymphocytes and are expressed by a wide variety of cells in the body.
CD137, a member of the tumor necrosis factor (TNF) receptor family, is a type 1 transmembrane protein, expressed on surfaces of leukocytes and non-immune cells. Its alternative names are tumor necrosis factor receptor superfamily member 9 (TNFRSF9), 4-1BB, and induced by lymphocyte activation (ILA). It is of interest to immunologists as a co-stimulatory immune checkpoint molecule, and as a potential target in cancer immunotherapy.
Lymphotoxin beta receptor (LTBR), also known as tumor necrosis factor receptor superfamily member 3 (TNFRSF3), is a cell surface receptor for lymphotoxin involved in apoptosis and cytokine release. It is a member of the tumor necrosis factor receptor superfamily.
CD27 is a member of the tumor necrosis factor receptor superfamily. It is currently of interest to immunologists as a co-stimulatory immune checkpoint molecule, and is the target of an anti-cancer drug in clinical trials.
Death receptor 4 (DR4), also known as TRAIL receptor 1 (TRAILR1) and tumor necrosis factor receptor superfamily member 10A (TNFRSF10A), is a cell surface receptor of the TNF-receptor superfamily that binds TRAIL and mediates apoptosis.
Lymphotoxin-alpha (LT-α) formerly known as tumor necrosis factor-beta (TNF-β) is a protein that in humans is encoded by the LTA gene. Belonging to the hematopoietic cell line, LT-α exhibits anti-proliferative activity and causes the cellular destruction of tumor cell lines. As a cytotoxic protein, LT-α performs a variety of important roles in immune regulation depending on the form that it is secreted as. Unlike other members of the TNF superfamily, LT-α is only found as a soluble homotrimer, when found at the cell surface it is found only as a heterotrimer with LTβ.
A proliferation-inducing ligand (APRIL), also known as tumor necrosis factor ligand superfamily member 13 (TNFSF13), is a protein of the TNF superfamily recognized by the cell surface receptor TACI. It is encoded by the TNFSF13 gene.
LIGHT, also known as tumor necrosis factor superfamily member 14 (TNFSF14), is a secreted protein of the TNF superfamily. It is recognized by herpesvirus entry mediator (HVEM), as well as decoy receptor 3.
Tumor necrosis factor ligand superfamily member 12 also known as TNF-related weak inducer of apoptosis (TWEAK) is a protein that in humans is encoded by the TNFSF12 gene.
Decoy receptor 3 (Dcr3), also known as tumor necrosis factor receptor superfamily member 6B (TNFRSF6B), TR6 and M68, is a soluble protein of the tumor necrosis factor receptor superfamily which inhibits Fas ligand-induced apoptosis.
Decoy receptor 1 (DCR1), also known as TRAIL receptor 3 (TRAILR3) and tumor necrosis factor receptor superfamily member 10C (TNFRSF10C), is a human cell surface receptor of the TNF-receptor superfamily.
Decoy receptor 2 (DCR2), also known as TRAIL receptor 4 (TRAILR4) and tumor necrosis factor receptor superfamily member 10D (TNFRSF10D), is a human cell surface receptor of the TNF-receptor superfamily.
Vascular endothelial growth inhibitor (VEGI), also known as TNF-like ligand 1A (TL1A) and TNF superfamily member 15 (TNFSF15), is protein that in humans is encoded by the TNFSF15 gene. VEGI is an anti-angiogenic protein. It belongs to tumor necrosis factor (ligand) superfamily, where it is member 15. It is the sole known ligand for death receptor 3, and it can also be recognized by decoy receptor 3.
Tumor necrosis factor receptor superfamily member 18 (TNFRSF18), also known as glucocorticoid-induced TNFR-related protein (GITR) or CD357. GITR is encoded and tnfrsf18 gene at chromosome 4 in mice. GITR is type I transmembrane protein and is described in 4 different isoforms. GITR human orthologue, also called activation-inducible TNFR family receptor (AITR), is encoded by the TNFRSF18 gene at chromosome 1.
Tumor necrosis factor ligand superfamily member 18 is a protein that in humans is encoded by the TNFSF18 gene.
Tumor necrosis factor (ligand) superfamily, member 12-member 13, also known as TNFSF12-TNFSF13, is a human gene.
BTB/POZ domain-containing protein TNFAIP1 is a protein that in humans is encoded by the TNFAIP1 gene.
Tumor necrosis factor receptor 2 (TNFR2), also known as tumor necrosis factor receptor superfamily member 1B (TNFRSF1B) and CD120b, is one of two membrane receptors that binds tumor necrosis factor-alpha (TNFα). Like its counterpart, tumor necrosis factor receptor 1 (TNFR1), the extracellular region of TNFR2 consists of four cysteine-rich domains which allow for binding to TNFα. TNFR1 and TNFR2 possess different functions when bound to TNFα due to differences in their intracellular structures, such as TNFR2 lacking a death domain (DD).
Interleukin 17 receptor D is a protein that in humans is encoded by the IL17RD gene.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.