Urokinase Plasminogen Activator Receptor (uPA-R)

The urokinase-type plasminogen activator (uPA) is one of two activators that converts the extracellular zymogen plasminogen to plasmin, a serine protease that is involved in a variety of normal and pathological processes that require cell migration and/or tissue destruction. uPA is synthesized and released from cells as a single-chain (sc) pro-enzyme with limited enzymatic activity and is converted to an active two-chain (tc) disulfide-linked active enzyme by plasmin and other specific proteinases. Both the scuPA and tcuPA bind with high-affinity to the cell surface via the glycosyl phosphatidylinositol-linked receptor uPAR which serves to localize the uPA proteolytic activity. The enzymatic activity of scuPA has also been shown to be enhanced by binding to uPAR. Independent of their proteolytic activity, the uPA/uPAR interaction also initiates signal transduction responses resulting in activation of protein tyrosine kinases, gene expression, cell adhesion, and chemotaxis. uPAR can interact with integrins to suppress normal integrin adhesive function and promote adhesion to vitronectin through a high affinity vitronectin binding site on uPAR. Mouse uPAR-1/Fc cDNA encodes a 327 amino acid residue precursor protein with a 23 aa residue signal peptide, seven potential N-linked glycosylation sites and a C-terminal GPI-anchor site. An alternate spliced variant of uPAR encoding a secreted soluble form of uPAR also exists. Human and mouse uPAR share approximately 60% amino acid sequence identity and the receptor-ligand interaction is highly species-specific. Human uPA binds rmuPAR at a lower affinity compared to rhuPAR. (Dear, A.E. and R.L. Medcalf, 1998, Eur. J. Biochemistry 252:185-193). A DNA sequence encoding amino acids 1-297 of mouse urokinase-type plasminogen activator receptor one (uPAR-1) (Kristensen, P. et al., 1991, J. Cell Biol. 115:1763-1771) was fused to the carboxy-terminal Fc region of human IgG1 via a linker peptide. The chimeric protein was expressed in a mouse myeloma cell line, NS0. Urokinase plasminogen activator (uPA) is a serine protease. It converts the abundant proenzyme plasminogen to active plasmin and plays a key role in cancer invasion and a variety of tissue remodelling processes such as wound healing, mammary gland involution and placental development. Elevated levels of uPA are associated with poor prognosis in many types of cancer. Applications: Suitable for use in ELISA, Immunohistochemistry. Other applications not tested. Recommended Dilution: Immunohistochemistry: 1:50-1:100. Frozen sections & paraffin sections. Pretreatment with 0.05% Pronase E for 20 minutes. Optimal dilutions to be determined by the researcher. Storage and Stability: Lyophilized powder may be stored at 4 degrees C for short-term only. Reconstitute to nominal volume by adding sterile 40-50% glycerol and store at -20 degrees C. Reconstituted product is stable for 12 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.