This page uses content from Wikipedia and is licensed under CC BY-SA.
suPAR, soluble urokinase-type plasminogen activator receptor, (NCBI Accession no. AAK31795) is the soluble form of uPAR. uPAR is a membrane bound receptor for uPA, otherwise known as urokinase as well as Vitronectin. 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.
suPAR has a secondary structure of 17 anti parallel β-sheets with 3 short α-helices. There are three homologous domains of suPAR: DI, DII, and DIII. In the comparison of cDNA sequences, DI differs from DII and DIII in its primary and tertiary structure, causing its distinct ligand binding properties.
The GPI-anchor links uPAR to the cell membrane making it available for uPA binding. When uPA is bound to the receptor, there is cleavage between the GPI-anchor and DIII, forming suPAR. There are three different suPAR forms: suPARI-III, suPARII-III, and suPARI. Of these three forms suPARII-III is known to be a chemotactic agent for promoting the immune system.
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. It has also been associated with organ damage in various diseases. 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 plasma.