- Other Names
- Megakaryocyte Colony Stimulating Factor (MKCSF), Myeloproliferative leukemia virus oncogene ligand (Mpl-ligand), Megakaryocyte growth and development factor (MGDF), THPO
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Thrombopoietin (TPO) plays an important role in regulating the level of circulating platelets in vivo. Megakaryopoiesis is the cellular process leading to platelet production. TPO binds to its receptor, the cellular homologue of the myeloproliferative leukemia virus oncogene (c-Mpl), and stimulates the proliferation and maturation of megakaryocytes. MPL does not possess kinase activity, thus the receptor associates with intracytoplasmic tyrosine kinases, janus kinase 2 (JAK2), for signal transduction. JAK2 is also important for MPL stability and cell-surface expression. TPO is able to promote the survival, self-renewal, and expansion of hematopoietic stem cells and primitive multi-lineage progenitor cells. TPO levels in blood and bone marrow are inversely related to platelet count. The regulation of TPO levels is mediated by its receptor c-Mpl (uptake and destruction). TPO is upregulated by PDGF and FGF-2, and it is downregulated by PF4, thrombospondin, and TGF-β in bone marrow stromal cells. In hepatocytes, HGF enhances TPO mRNA expression. During acute-phase response, IL-6 induces TPO transcription in the liver. Increased TPO concentrations are present in the cerebrospinal fluid of some patients with bacterial or viral meningitis. Also, elevated plasma TPO levels exist in several hematological diseases associated with thrombocytopenia, coronary syndromes, and sepsis.Product Details
- Rat Thrombopoietin (TPO), amino acids (Ser22-Ser326) (Accession# NM_031133), was expressed in CHO cells. The N terminal contains a 9His-2(SGGG)-IEGR-tag.
- Molecular Mass
- The 326 amino acid recombinant protein has a predicted molecular mass of approximately 34.4 kD. The protein migrates at approximately 60-70 kD in DTT-reducing and non-reducing conditions by SDS-PAGE. The predicted N-terminal amino acid is His.
- >95%, as determined by Coomassie stained SDS-PAGE.
- 0.22 µm filtered protein solution is in PBS, pH 7.2.
- Endotoxin Level
- Less than 0.01 ng per µg cytokine as determined by the LAL method.
- 10 and 25 µg sizes are bottled at 100 µg/mL.
- Storage & Handling
- Unopened vial can be stored between 2°C and 8°C for up to 2 weeks, at -20°C for up to six months, or at -70°C or colder until the expiration date. For maximum results, quick spin vial prior to opening. The protein can be aliquoted and stored at -20°C or colder. Stock solutions can also be prepared at 50 - 100 µg/mL in appropriate sterile buffer, carrier protein such as 0.2 - 1% BSA or HSA can be added when preparing the stock solution. Aliquots can be stored between 2°C and 8°C for up to one week and stored at -20°C or colder for up to 3 months. Avoid repeated freeze/thaw cycles.
- ED50 = 0.08-0.4 ng/ml, corresponding to a specific activity of 2.5 - 12.5 x 106 units/mg, as determined by induction of proliferation of MO7e megakaryocytic leukemia cell line.
- Application Notes
BioLegend carrier-free recombinant proteins provided in liquid format are shipped on blue-ice. Our comparison testing data indicates that when handled and stored as recommended, the liquid format has equal or better stability and shelf-life compared to commercially available lyophilized proteins after reconstitution. Our liquid proteins are validated in-house to maintain activity after shipping on blue ice and are backed by our 100% satisfaction guarantee. If you have any concerns, contact us at firstname.lastname@example.org.
- Growth factor.
- TPO is produced by the liver and kidney and is expressed in the central nervous system and bone marrow.
- TPO regulates the megakaryocytopoiesis and thrombopoiesis.
- Megakaryocytes, platelets, hemangioblasts, hematopoietic stem cells, and endothelial cells.
- TpoR (c-Mpl, MPL)
- Cell Type
- Mesenchymal Stem Cells, Hematopoietic stem and progenitors, Embryonic Stem Cells
- Biology Area
- Apoptosis/Tumor Suppressors/Cell Death, Cell Biology, Stem Cells
- Molecular Family
- Growth Factors, Cytokines/Chemokines
- Antigen References
1. Drachman JG, et al. 1995. J. Biol. Chem. 270:4979.
2. Royer Y, et al. 2005. J. Biol. Chem. 280:27251.
3. Kaushansky K. 2005. J. Clin. Invest. 115:3339.
4. de Graaf CA and Metcalf D. 2011. Cell Cycle 10:1582.
5. Zhang J, et al. 2010. J. Interferon Cytokine Res. 7:465.
6. Lupia E, et al. 2012. Mediators Inflamm. 2012:390892.
7. Besancenot R, et al. 2014. Blood 124:2104.
- Gene ID
- 81811 View all products for this Gene ID
- View information about Thrombopoietin on UniProt.org
- Does specific activity of a recombinant protein vary between lots?
Specific activity will vary for each lot and for the type of experiment that is done to validate it, but all passed lots will have activity within the established ED50 range for the product and we guarantee that our products will have lot-to-lot consistency. Please conduct an experiment-specific validation to find the optimal ED50 for your system.
- Have your recombinants been tested for stability?
Our testing shows that the recombinant proteins are able to withstand room temperature for a week without losing activity. In addition the recombinant proteins were also found to withstand four cycles of freeze and thaw without losing activity.
- How do you convert activity as an ED50 in ng/ml to a specific activity in Units/mg?
- Use formula Specific activity (Units/mg) = 10e6/ ED50 (ng/mL)
- How does the activity of your recombinant proteins compare to competitors?
We quality control each and every lot of recombinant protein. Not only do we check its bioactivity, but we also compare it against other commercially available recombinant proteins. We make sure each recombinant protein’s activity is at least as good as or better than the competition’s. In order to provide you with the best possible product, we ensure that our testing process is rigorous and thorough. If you’re curious and eager to make the switch to BioLegend recombinants, contact your sales representative today!
- What is the specific activity or ED50 of my recombinant protein?
The specific activity range of the protein is indicated on the product datasheets. Because the exact activity values on a per unit basis can largely fluctuate depending on a number of factors, including the nature of the assay, cell density, age of cells/passage number, culture media used, and end user technique, the specific activity is best defined as a range and we guarantee the specific activity of all our lots will be within the range indicated on the datasheet. Please note this only applies to recombinants labeled for use in bioassays. ELISA standard recombinant proteins are not recommended for bioassay usage as they are not tested for these applications.