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| Thrombospondin-1 | |||||||||
| Identifiers | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Symbol | TSP_1 | ||||||||
| Pfam | PF00090 | ||||||||
| InterPro | IPR000884 | ||||||||
| SMART | SM00209 | ||||||||
| PROSITE | PS50092 | ||||||||
| SCOP | 1lsl | ||||||||
| SUPERFAMILY | 1lsl | ||||||||
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Thrombospondins (TSP) are secreted proteins with antiangiogenic abilities. TSP was discovered by Nancy L. Baenziger.[1]
Contents |
Types [link]
The thrombospondins (TSP) are a family of multifunctional proteins. The family consists of thrombospondins 1-5 and can be divided into 2 subgroups: A, which contains TSP-1 and -2, and B, which contains TSP-3, -4 and -5 (also designated cartilage oligomeric protein or COMP). TSP-1 and -2 are homotrimers, consisting of three identical subunits, whereas TSP-3, -4 and -5 are homopentamers.
TSP-1 and TSP-2 are produced by immature astrocytes during brain development, which promotes the development of new synapses.[2]
Thrombospondin 1 [link]
Thrombospondin 1 (TSP-1) is encoded by THBS1. It was first isolated from platelets that had been stimulated with thrombin, and so was designated 'thrombin-sensitive protein'.[1] Since its first recognition, functions for TSP-1 have been found in multiple biological processes including angiogenesis, apoptosis, activation of TGF-beta and Immune regulation. As such, TSP-1 is designated a multifunctional protein.
TSP-1 has multiple receptors, among which CD36, CD47 and integrins are of particular note.
TSP-1 is an antiangiogenic, inhibiting the proliferation and migration of endothelial cells by interactions with CD36 expressed on their surface of these cells. Inhibitory peptides and fragments of TSP1 bind to CD36, leading to the expression of FAS ligand (FasL), which activates its specific, ubiquitous receptor, Fas. This leads to the activation of caspases and apoptosis of the cell. Since tumors overexpressing TSP-1 typically grow slower, exhibit less angiogenesis, and have fewer metastases, TSP1 is an attractive target for cancer treatment. Because TSP1 is extremely large (~120 kDa monomer), not very abundant and exerts multiple actions, its clinical usefulness is questionable. However, small-molecules based on a CD36-binding peptide sequence from TSP1 are being tested. One analog, ABT-510, exhibits potent proapoptotic activity in cultured cells, while clinically it is very well tolerated with therapeutic benefits reported against several malignancies.[3] ABT-510 is being evaluated in phase II clinical trials for the treatment of several types of cancer.[4]
Human proteins containing this domain [link]
ADAMTS1; ADAMTS10; ADAMTS12; ADAMTS13; ADAMTS14; ADAMTS15; ADAMTS16; ADAMTS17; ADAMTS18; ADAMTS19; ADAMTS2; ADAMTS20; ADAMTS3; ADAMTS4; ADAMTS5; ADAMTS6; ADAMTS7; ADAMTS8; ADAMTS9; ADAMTSL1; ADAMTSL2; ADAMTSL3; ADAMTSL4; ADAMTSL5; BAI1; BAI2; BAI3; C6; C7; C8A; C8B; C9; C9orf8; C9orf94; CFP; CILP; CILP2; CTGF; CYR61; HMCN1; LIBC; NOV; PAPLN; RSPO1; RSPO3; SEMA5A; SEMA5B; SPON1; SPON2; SSPO; THBS1; THBS2; THSD1; THSD3; THSD7A; THSD7B; UNC5A; UNC5B; UNC5C; UNC5D; WISP1; WISP2; WISP3;
References [link]
- ^ a b Baenziger NL, Brodie GN, Majerus PW (January 1971). "A Thrombin-Sensitive Protein of Human Platelet Membranes". Proc. Natl. Acad. Sci. U.S.A. 68 (1): 240–3. DOI:10.1073/pnas.68.1.240. PMC 391203. PMID 5276296. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=391203.
- ^ Christopherson KS, Ullian EM, Stokes CC,Mullowney CE, Hell JW, Agah A, Lawler J, Mosher DF, Bornstein P, Barres BA. (2005). "Thrombospondins are astrocyte-secreted proteins that promote CNS synaptogenesis". Cell 120 (3): 421–33. DOI:10.1016/j.cell.2004.12.020. PMID 15707899.
- ^ Haviv F, Bradley MF, Kalvin DM, et al. (April 2005). "Thrombospondin-1 mimetic peptide inhibitors of angiogenesis and tumor growth: design, synthesis, and optimization of pharmacokinetics and biological activities". Journal of Medicinal Chemistry 48 (8): 2838–46. DOI:10.1021/jm0401560. PMID 15828822.
- ^ Sorbera LA, Bayes M (2005). "ABT-510: oncolytic angiogenesis inhibitor". Drugs of the future (Prous Science) 30 (11): 1081–6. DOI:10.1358/dof.2005.030.11.949588.
External links [link]
- Thrombospondins at the US National Library of Medicine Medical Subject Headings (MeSH)
- THBS1, THBS2, THBS3, THBS4, COMP (also known as "THBS5")
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Thrombospondin 1
Thrombospondin 1, also known as THBS1, is a protein that in humans is encoded by the THBS1 gene.
Thrombospondin 1 is a subunit of a disulfide-linked homotrimeric protein. This protein is an adhesive glycoprotein that mediates cell-to-cell and cell-to-matrix interactions. This protein can bind to fibrinogen, fibronectin, laminin, type V collagen and integrins alpha-V/beta-1. This protein has been shown to play roles in platelet aggregation, angiogenesis, and tumorigenesis.
Function
The thrombospondin-1 protein is a member of the thrombospondin family. It is a multi-domain matrix glycoprotein that has been shown to be a natural inhibitor of neovascularization and tumorigenesis in healthy tissue. Both positive and negative modulation of endothelial cell adhesion, motility, and growth have been attributed to TSP1. This should not be surprising considering that TSP1 interacts with at least 12 cell adhesion receptors, including CD36, αv integrins, β1 integrins, syndecan, and integrin-associated protein (IAP or CD47). It also interacts with numerous proteases involved in angiogenesis, including plasminogen, urokinase, matrix metalloproteinase, thrombin, cathepsin, and elastase.
