Thrombomodulin

Last updated
THBD
Protein THBD PDB 1adx.png
Available structures
PDB Ortholog search: PDBe RCSB
Identifiers
Aliases THBD , AHUS6, BDCA3, CD141, THPH12, THRM, TM, thrombomodulin
External IDs OMIM: 188040 MGI: 98736 HomoloGene: 308 GeneCards: THBD
Gene location (Human)
Ideogram human chromosome 20.svg
Chr. Chromosome 20 (human) [1]
Human chromosome 20 ideogram.svg
HSR 1996 II 3.5e.svg
Red rectangle 2x18.png
Band 20p11.21Start23,045,633 bp [1]
End23,049,672 bp [1]
RNA expression pattern
PBB GE THBD 203888 at fs.png

PBB GE THBD 203887 s at fs.png
More reference expression data
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_000361

NM_009378

RefSeq (protein)

NP_000352

NP_033404

Location (UCSC) Chr 20: 23.05 – 23.05 Mb Chr 2: 148.4 – 148.41 Mb
PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Thrombomodulin (TM), CD141 or BDCA-3 is an integral membrane protein expressed on the surface of endothelial cells and serves as a cofactor for thrombin. It reduces blood coagulation by converting thrombin to an anticoagulant enzyme from a procoagulant enzyme. [5] Thrombomodulin is also expressed on human mesothelial cell, [6] monocyte and a dendritic cell subset.

Genetics and structure

In humans, thrombomodulin is encoded by the THBD gene. [7] The protein has a molecular mass of 74kDa, and consists of a single chain with six tandemly repeated EGF-like domains, a Serine/Threonine-rich spacer and a transmembrane domain. [8] It is a member of the C-type lectin domain (CTLD) group 14 family. [9]

Function

Thrombomodulin functions as a cofactor in the thrombin-induced activation of protein C in the anticoagulant pathway by forming a 1:1 stoichiometric complex with thrombin. This raises the speed of protein C activation thousandfold. Thrombomodulin-bound thrombin has procoagulant effect at the same time by inhibiting fibrinolysis by cleaving thrombin-activatable fibrinolysis inhibitor (TAFI, aka carboxypeptidase B2) into its active form.[ citation needed ]

Thrombomodulin is a glycoprotein on the surface of endothelial cells that, in addition to binding thrombin, regulates C3b inactivation by factor I. Mutations in the thrombomodulin gene (THBD) have also been reported to be associated with atypical hemolytic-uremic syndrome (aHUS).[ citation needed ]

The antigen described as BDCA-3 [10] has turned out to be identical to thrombomodulin. [11] Thus, it was revealed that this molecule also occurs on a very rare (0.02%) subset of human dendritic cells called MDC2. Its function on these cells is unknown.[ citation needed ]

Interactions

Thrombomodulin has been shown to interact with thrombin. [12] [13]

Related Research Articles

Coagulation Process by which blood changes from a liquid to a gel, forming a blood clot

Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot. It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The mechanism of coagulation involves activation, adhesion and aggregation of platelets, as well as deposition and maturation of fibrin.

Thrombin Enzyme in humans

Thrombin is a serine protease, an enzyme that, in humans, is encoded by the F2 gene. Prothrombin is proteolytically cleaved to form thrombin in the clotting process. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalyzing many other coagulation-related reactions.

Factor VIII essential blood-clotting protein found in Homo sapiens

Factor VIII (FVIII) is an essential blood-clotting protein, also known as anti-hemophilic factor (AHF). In humans, factor VIII is encoded by the F8 gene. Defects in this gene result in hemophilia A, a recessive X-linked coagulation disorder. Factor VIII is produced in liver sinusoidal cells and endothelial cells outside the liver throughout the body. This protein circulates in the bloodstream in an inactive form, bound to another molecule called von Willebrand factor, until an injury that damages blood vessels occurs. In response to injury, coagulation factor VIII is activated and separates from von Willebrand factor. The active protein interacts with another coagulation factor called factor IX. This interaction sets off a chain of additional chemical reactions that form a blood clot.

Von Willebrand factor mammalian protein found in Homo sapiens

von Willebrand factor (VWF) is a blood glycoprotein involved in hemostasis. It is deficient and/or defective in von Willebrand disease and is involved in many other diseases, including thrombotic thrombocytopenic purpura, Heyde's syndrome, and possibly hemolytic–uremic syndrome. Increased plasma levels in many cardiovascular, neoplastic, and connective tissue diseases are presumed to arise from adverse changes to the endothelium, and may predict an increased risk of thrombosis.

Factor IX mammalian protein found in Homo sapiens

Factor IX is one of the serine proteases of the coagulation system; it belongs to peptidase family S1. Deficiency of this protein causes haemophilia B. It was discovered in 1952 after a young boy named Stephen Christmas was found to be lacking this exact factor, leading to haemophilia.

Protein S protein-coding gene in the species Homo sapiens

Protein S is a vitamin K-dependent plasma glycoprotein synthesized in the liver. In the circulation, Protein S exists in two forms: a free form and a complex form bound to complement protein C4b-binding protein (C4BP). In humans, protein S is encoded by the PROS1 gene.

Protein C mammalian protein found in Homo sapiens

Protein C, also known as autoprothrombin IIA and blood coagulation factor XIX, is a zymogen, the activated form of which plays an important role in regulating anticoagulation, inflammation, and cell death and maintaining the permeability of blood vessel walls in humans and other animals. Activated protein C (APC) performs these operations primarily by proteolytically inactivating proteins Factor Va and Factor VIIIa. APC is classified as a serine protease since it contains a residue of serine in its active site. In humans, protein C is encoded by the PROC gene, which is found on chromosome 2.

Factor X mammalian protein found in Homo sapiens

Factor X, also known by the eponym Stuart–Prower factor, is an enzyme of the coagulation cascade. It is a serine endopeptidase. Factor X is synthesized in the liver and requires vitamin K for its synthesis.

Factor V mammalian protein found in Homo sapiens

Factor V is a protein of the coagulation system, rarely referred to as proaccelerin or labile factor. In contrast to most other coagulation factors, it is not enzymatically active but functions as a cofactor. Deficiency leads to predisposition for hemorrhage, while some mutations predispose for thrombosis.

Complement component 3 protein-coding gene in the species Homo sapiens

Complement component 3, often simply called C3, is a protein of the immune system. It plays a central role in the complement system and contributes to innate immunity. In humans it is encoded on chromosome 19 by a gene called C3.

The prothrombinase complex consists of the serine protease, Factor Xa, and the protein cofactor, Factor Va. The complex assembles on negatively charged phospholipid membranes in the presence of calcium ions. The prothrombinase complex catalyzes the conversion of prothrombin (Factor II), an inactive zymogen, to thrombin (Factor IIa), an active serine protease. The activation of thrombin is a critical reaction in the coagulation cascade, which functions to regulate hemostasis in the body. To produce thrombin, the prothrombinase complex cleaves two peptide bonds in prothrombin, one after Arg271 and the other after Arg320. Although it has been shown that Factor Xa can activate prothrombin when unassociated with the prothrombinase complex, the rate of thrombin formation is severely decreased under such circumstances. The prothrombinase complex can catalyze the activation of prothrombin at a rate 3 x 105-fold faster than can Factor Xa alone. Thus, the prothrombinase complex is required for the efficient production of activated thrombin and also for adequate hemostasis.

Heparin cofactor II protein-coding gene in the species Homo sapiens

Heparin cofactor II (HCII), a protein encoded by the SERPIND1 gene, is a coagulation factor that inhibits IIa, and is a cofactor for heparin and dermatan sulfate.

CD46 mammalian protein found in Homo sapiens

CD46 complement regulatory protein also known as CD46 and Membrane Cofactor Protein is a protein which in humans is encoded by the CD46 gene. CD46 is an inhibitory complement receptor.

Complement factor I protein-coding gene in the species Homo sapiens

Complement factor I, also known as C3b/C4b inactivator, is a protein that in humans is encoded by the CFI gene. Complement factor I is a protein of the complement system, first isolated in 1966 in guinea pig serum, that regulates complement activation by cleaving cell-bound or fluid phase C3b and C4b. It is a soluble glycoprotein that circulates in human blood at an average concentration of 35 μg/mL.

EMR2 protein-coding gene in the species Homo sapiens

EGF-like module-containing mucin-like hormone receptor-like 2 also known as CD312 is a protein encoded by the ADGRE2 gene. EMR2 is a member of the adhesion GPCR family. Adhesion GPCRs are characterized by an extended extracellular region often possessing N-terminal protein modules that is linked to a TM7 region via a domain known as the GPCR-Autoproteolysis INducing (GAIN) domain.

EMR3 protein-coding gene in the species Homo sapiens

EGF-like module-containing mucin-like hormone receptor-like 3 is a protein encoded by the ADGRE3 gene. EMR3 is a member of the adhesion GPCR family. Adhesion GPCRs are characterized by an extended extracellular region often possessing N-terminal protein modules that is linked to a TM7 region via a domain known as the GPCR-Autoproteolysis INducing (GAIN) domain.

Fibrinogen alpha chain protein-coding gene in the species Homo sapiens

Fibrinogen alpha chain is a protein that in humans is encoded by the FGA gene.

EGF-like domain Protein domain named after the epidermal growth factor protein

The EGF-like domain is an evolutionary conserved protein domain, which derives its name from the epidermal growth factor where it was first described. It comprises about 30 to 40 amino-acid residues and has been found in a large number of mostly animal proteins. Most occurrences of the EGF-like domain are found in the extracellular domain of membrane-bound proteins or in proteins known to be secreted. An exception to this is the prostaglandin-endoperoxide synthase. The EGF-like domain includes 6 cysteine residues which in the epidermal growth factor have been shown to form 3 disulfide bonds. The structures of 4-disulfide EGF-domains have been solved from the laminin and integrin proteins. The main structure of EGF-like domains is a two-stranded β-sheet followed by a loop to a short C-terminal, two-stranded β-sheet. These two β-sheets are usually denoted as the major (N-terminal) and minor (C-terminal) sheets. EGF-like domains frequently occur in numerous tandem copies in proteins: these repeats typically fold together to form a single, linear solenoid domain block as a functional unit.

Carboxypeptidase B2 mammalian protein found in Homo sapiens

Carboxypeptidase B2 (CPB2), also known as carboxypeptidase U (CPU), plasma carboxypeptidase B (pCPB) or thrombin-activatable fibrinolysis inhibitor (TAFI), is an enzyme that, in humans, is encoded by the gene CPB2.

Atypical hemolytic uremic syndrome (aHUS) is an extremely rare, life-threatening, progressive disease that frequently has a genetic component. In most cases it can be effectively controlled by interruption of the complement cascade. Particular monoclonal antibodies, discussed later in the article, have proven efficacy in many cases.

References

  1. 1 2 3 GRCh38: Ensembl release 89: ENSG00000178726 - Ensembl, May 2017
  2. 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000074743 - Ensembl, May 2017
  3. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. IPR001491 Thrombomodulin Accessed January 19, 2012.
  6. Verhagen HJ, Heijnen-Snyder GJ, Pronk A, Vroom TM, van Vroonhoven TJ, Eikelboom BC, Sixma JJ, de Groot PG (Dec 1996). "Thrombomodulin activity on mesothelial cells: perspectives for mesothelial cells as an alternative for endothelial cells for cell seeding on vascular grafts". British Journal of Haematology. 95 (3): 542–9. doi:10.1046/j.1365-2141.1996.d01-1935.x. PMID   8943899.
  7. Wen DZ, Dittman WA, Ye RD, Deaven LL, Majerus PW, Sadler JE (Jul 1987). "Human thrombomodulin: complete cDNA sequence and chromosome localization of the gene". Biochemistry. 26 (14): 4350–7. doi:10.1021/bi00388a025. PMID   2822087.
  8. Sadler JE (Jul 1997). "Thrombomodulin structure and function". Thrombosis and Haemostasis. 78 (1): 392–5. doi:10.1055/s-0038-1657558. PMID   9198185.
  9. Khan KA, McMurray JL, Mohammed FM, Bicknell R. "C-type lectin domain group 14 proteins in vascular biology, cancer and inflammation". FEBS Journal. PMID   31287944.CS1 maint: multiple names: authors list (link)
  10. Dzionek A, Fuchs A, Schmidt P, Cremer S, Zysk M, Miltenyi S, Buck DW, Schmitz J (Dec 2000). "BDCA-2, BDCA-3, and BDCA-4: three markers for distinct subsets of dendritic cells in human peripheral blood". Journal of Immunology. 165 (11): 6037–46. doi: 10.4049/jimmunol.165.11.6037 . PMID   11086035.
  11. Dzionek A, Inagaki Y, Okawa K, Nagafune J, Röck J, Sohma Y, Winkels G, Zysk M, Yamaguchi Y, Schmitz J (Dec 2002). "Plasmacytoid dendritic cells: from specific surface markers to specific cellular functions". Human Immunology. 63 (12): 1133–48. doi:10.1016/S0198-8859(02)00752-8. PMID   12480257.
  12. Bajzar L, Morser J, Nesheim M (Jul 1996). "TAFI, or plasma procarboxypeptidase B, couples the coagulation and fibrinolytic cascades through the thrombin-thrombomodulin complex". The Journal of Biological Chemistry. 271 (28): 16603–8. doi: 10.1074/jbc.271.28.16603 . PMID   8663147.
  13. Jakubowski HV, Owen WG (Jul 1989). "Macromolecular specificity determinants on thrombin for fibrinogen and thrombomodulin". The Journal of Biological Chemistry. 264 (19): 11117–21. PMID   2544585.

Further reading