Description

Nori Human suPAR ELISA Kit Summary

Alternative names for suPAR: The Urokinase receptor, urokinase-type plasminogen activator receptor (uPAR), CD87 (Cluster of Differentiation 87),

Standard Curve

Kit Components
1. Pre-coated 96-well Microplate
2. Biotinylated Detection Antibody
3. Streptavidin-HRP Conjugate
4. Lyophilized Standards
5. TMB One-Step Substrate
6. Stop Solution
7. 20 x PBS
8. Assay Buffer

Other Materials Required but not Provided:
1. Microplate Reader capable of measuring absorption at 450 nm
2. Log-log graph paper or computer and software for ELISA data analysis
3. Precision pipettes (1-1000 µl)
4. Multi-channel pipettes (300 µl)
5. Distilled or deionized water

Protocol Outline
1. Prepare all reagents, samples and standards as instructed in the datasheet.
2. Add 100 µl of Standard or samples to each well and incubate 1 h at RT.
3. Add 100 µl of Working Detection Antibody to each well and incubate 1 h at RT.
4. Add 100 µl of Working Streptavidin-HRP to each well and incubate 20 min at RT.
5. Add 100 µl of Substrate to each well and incubate 5-30 min at RT.
6. Add 50 µl of Stop Solution to each well and read at 450 nm immediately.

Background: 

The Urokinase receptor, also known as urokinase-type plasminogen activator receptor (uPAR) or CD87 (Cluster of Differentiation 87), is a multidomain glycoprotein tethered to the cell membrane with a glycosylphosphotidylinositol (GPI) anchor. uPAR was originally identified as a saturable binding site for urokinase on the cell surface. uPAR consists of three different domains of the three-finger protein domain family, which also includes domains found in lymphocyte antigen 6 and in snake venom toxins of the three-finger toxin family, such as alpha-neurotoxins.^[1] uPAR is a part of the plasminogen activation system, which in the healthy body is involved in tissue reorganization events such as mammary gland involution and wound healing. In order to reorganize tissue, the old tissue must be able to be degraded. An important mechanism in this degradation is the proteolysis cascade initiated by the plasminogen activation system. uPAR binds urokinase and thus restricts plasminogen activation to the immediate vicinity of the cell membrane. Thus uPAR seems to be an important player in the regulation of this process. However, the components of the plasminogen activation system are highly expressed in many malignant tumors, indicating that tumors are able to hijack the system, and use it in metastasis. Besides the primary ligand urokinase, uPAR interacts with several other proteins such as vitronectin, the uPAR associated protein (uPARAP) and the integrin family of membrane proteins. suPAR (NCBI Accession no. AAK31795) is the soluble form of uPAR. suPAR results from the cleavage and release of membrane-bound uPAR. suPAR concentration positively correlates to the activation level of the immune system and is present in plasma, urine, blood, serum, and cerebrospinal fluid. suPAR is a marker of disease severity and aggressiveness.^[2] There are three different suPAR forms: suPARI-III, suPARII-III, and suPARI. suPARII-III is known to be a chemotactic agent for promoting the immune system.^[2] suPAR is a biomarker for activation of the inflammatory and immune systems. suPAR levels are positively correlated with pro-inflammatory biomarkers, such as tumor necrosis factor-α, leukocyte counts, and C-reactive protein. SuPAR is associated with organ damage in various diseases.^[3][4][5][6] Elevated levels of suPAR are associated with increased risk of systemic inflammatory response syndrome (SIRS), cancer, Focal segmental glomerulosclerosis, cardiovascular disease, type 2 diabetes, infectious diseases, HIV, and mortality. suPARnostic is a prognostic test used to detect suPAR levels in blood.

References

1. Kessler, et al. (2017). Journal of Neurochemistry. 142: 7–18.
2. Thunø, Maria; et al. (2009). Disease Markers. 27(3–4): 157–72.
3. Enocsson, Helena; Sjöwall, Christopher (2015) Clinica Chimica Acta. 444: 234–241.
4. Enocsson, Helena; et al. (2013). Translational Research. 162(5): 287–296.
5. Sjöwall, C; et al. (2014). Translational Research. 165(6): 658–66.
6. Hahm, E; et al. (2016). Nature Medicine. 23(1): 100–106.

Product Citations