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Osteopontin, also known as secreted phosphoprotein 1 (SPP1) and early T lymphocytes activation 1 (ETA-1), is an arginine-glycine-aspartic acid (RGD) that contains multi-functional glycoproteins who are able to interact with integrins and CD44 as receptors. This protein has been shown to play roles in cell migration and survival, bone remodeling, regulation of immune cell functions, apoptosis, control of tumor cell phenotypes, and autoimmune diseases. Osteopontin is involved in recruiting and stimulating macrophages and lymphocytes in response to microbial infections. The Osteopontin receptor-ligand interaction mediates chemotaxis or attachment that depends on whether the protein is in soluble or immobilized form. Osteopontin has also been shown to play a role in the progression of cancer, which is supported by the finding that patients who suffer from disseminated carcinoma also have increased levels of Osteopontin in their plasma. In addition, Osteopontin is a component of the human atherosclerotic plaque and may be a mediator of arterial neointima formation. It is synthesized by macrophage, smooth muscle, and endothelial cells in primary and recurrent human coronary atherosclerotic plaques, which may contribute to the cellular accumulations and dystrophic calcification in the atherosclerotic plaques. Osteopontin is also a substrate for MMP-3, MMP-7, MMP-9, MMP-12, and thrombin within the SVVYGLR motif.Product Details
- Human Osteopontin, amino acids (Ile17-Asn300) (Accession# NP_000573.1), was expressed in 293E cells with a C-terminal His tag.
- Molecular Mass
- The 290 amino acid recombinant protein has a predicted molecular mass of approximately 33 kD. The DTT-reduced and non-reduced protein migrates approximately 55 kD by SDS-PAGE. The predicted N-terminal amino acid is Ile.
- >95%, as determined by Coomassie stained SDS-PAGE.
- 0.22 µm filtered protein solution is in PBS, pH 7.2.
- Endotoxin Level
- Less than 1.0 EU per µg of protein as determined by the LAL method.
- 10 and 25 µg sizes are bottled at 200 µg/mL. 100 µg size and larger sizes are lot-specific and bottled at the concentration indicated on the vial (please contact technical support for concentration, or use our Lookup tool if you have a lot number.) Please note, new lots of the 100 µg size will be lot-specific and may differ from previous lots that had a fixed concentration.
- 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.
- Human Osteopontin, when immobilized with anti-CD3 antibody, is able to inhibit IFN-γ secretion in human T cells in a dose-dependent manner with an ED50 of 0.5 - 2.0 µg/mL.
- Application Notes
- Increasing concentrations of hOsteopontin, along wtih 500 ng/ml of anti-CD3 antibody (OKT3), were used to coat a 96-well plate overnight.
- Excess hOsteopontin and OKT3 were washed away with PBS before incubating purified human T cells at 2 X 105 cells per well.
- The supernatant cell culture was collected after 24 - 48 hours of incubation and the concentration of IFN-γ was detected using BioLegend's Human IFN-γ ELISA MAX™ Deluxe (Cat No: 430104).
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 verified 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 email@example.com.
(PubMed link indicates BioLegend citation)
- O'Regan AW, et al. 2000. J. Leuko. Biol. 68:495.
- Osteoblasts, osteoclasts, endothelial cells, macrophages, and smooth muscle cells.
- Plays a role in cell migration, survival, inhibition of calcification, and regulation of immune cell function. Hypocalcemia and hypophosphatemia leads to an increase in Osteopontin transcription, translation, and secretion.
- T cells, neutrophils, macrophages, osteoclasts, and mast cells.
- CD44, integrins (αVβ3).
- Human OPN1 inhibits IFN-γ secretion by anti-CD3 activated human T cells.
- Biology Area
- Apoptosis/Tumor Suppressors/Cell Death, Cancer Biomarkers, Cell Biology, Cell Motility/Cytoskeleton/Structure, Immunology, Signal Transduction, Stem Cells
- Molecular Family
- Antigen References
1. Wang KX and Denhardt DT. 2008. Cytokine Growth Factor Rev. 333.
2. Agnihotri R, et al. 2001. J. Biol. Chem. 276:28261.
3. O'Regan AW, et al. 2000. J. Leuko. Biol. 68:495.
4. Yokosaki Y, et al. 2005. Matrix Biol. 24:418.
5. Rangaswami H, et al. 2006. Trends Cell Biol. 16:79.
- Gene ID
- 6696 View all products for this Gene ID
- View information about Osteopontin 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.