What is suPAR?
suPAR (soluble urokinase plasminogen activating receptor) is a protein in the blood.
The plasma level of suPAR reflects immune activation and is increased in several infectious diseases, such as HIV-1-infection, malaria, tuberculosis, Streptococcus pneumonia bacteraemia, sepsis, pneumococcal pneumonia and bacterial and viral CNS infection.
Furthermore, high suPAR levels are associated with increased inflammation, disease progression and fatal outcome. Measuring suPAR levels can thus serve as a marker to monitor disease progression and treatment [1,2,3,4,5,6].
suPAR levels can be measured easily with the novel suPARnostic® ELISA kit. Compared to other applicable products, this CE/IVD approved kit provides fast and reproducible results. Moreover, this product is backed by patent rights to use the marker in various disease conditions.
What is suPAR?
suPAR is the soluble form of the urokinase-type plasminogen activator receptor (uPAR), a three domain receptor mainly expressed on immune cells, including neutrophils, activated T-cells, and macrophages.
Figure 1 | Schematic representation of urokinase receptor The GPI-anchor links uPAR to the cell membrane making it available for uPA to bind to the receptor. When the receptor is cleaved between the GPI-anchor and D3, it becomes soluble (suPAR). suPAR is a stable protein that can be measured in various body fluids. uPA: urokinase-type plasminogen activator, uPAR: uPA receptor, suPAR: soluble uPAR, 1: Domain 1, D2: Domain 2, D3: Domain 3
The membrane-bound uPAR is illustrated in figure 1.A. A glycosylphosphatidylinositol (GPI)-anchor is linking the protein to the membrane, but once this anchor is cleaved the protein is released from the membrane and becomes soluble as illustrated in figure 1.B.
uPAR is linked to the cell membrane by a glycosyl phosphatidylinositol (GPI)-anchor and binding of urokinase plasminogen activator (uPA) to uPAR, facilitates cleavage of the anchor and hence shedding of the receptor (Fig 1.). The soluble receptor, suPAR, is measurable in human body fluids including plasma, serum, urine, sputum, saliva and cerebrospinal fluid.
uPAR and its ligand are involved in numerous physiological and pathological pathways which include the plasminogen activating pathway, regulation of pericellular proteolysis, modulation of cell adhesion, migration and proliferation through interactions with proteins present in the extracellular matrix. The involvement of the soluble form of the receptor in the inflammation process is well documented although the actual biological function of the molecule is still not clear. Studies suggest that suPAR is a regulator of uPAR/uPA actions through competitive inhibition of uPAR and several studies conclude that the cleaved receptor is a chemotatic agent promoting the immune response.
1: Sidenius N, Sier CFM, Ullum H, Pedersen BK, Cozzi LA, Blasi F, and Eugen-Olsen J, (2000) The American Society of Hematology, 96, 4091-4095
2: Wittenhaugen P, Kronborg G, Weis N, Nielsen H, Obel N, Pedersen SS, and Eugen-Olsen J, (2004) European Society of Clinical Microbiology and Infectious Diseases, 10, 409-415
3: Østergaard C, Benfield T, Lundgren JD, and Eugen-Olsen J, (2004) Scand J Infect Dis, 36, 14-19
4: Kofoed K, Eugen-Olsen J, Petersen J, Larsen K, and Andersen O, (2008) Eur J Clin Microbiol Infect Dis
5: Ostrowski SR, Ullum H, Goka BQ, Høyer-Hansen G, Obeng-Adjei G, Pedersen BK, Akanmori BD, and Kurtzhals JAL, (2005) The Journal of Infectious Diseases, 191, 1331-1341
6: Eugen-Olsen J, Gustafson P, Sidenius N, Fischer TK, Parner J, Aaby P, Gomes VF, Lisse I, (2002) Int J Tuberc Lung Dis, 6, 686-692
7: Huai Q, Mazar AP, Kuo A, Parry GC, Shaw DE, Callahan J, Li Y, Yuan C, Bian C, Chen L, Furie B, Furie BC, Cines
For information about how to measure suPAR, please look under
What is suPARnostic®?
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Products - suPAR Stability