Description: The human Osteopontin ELISA is an enzyme-linked immunosorbent assay for the quantitative detection of human Osteopontin. The human Osteopontin ELISA is for research use only. Not for diagnostic or therapeutic procedures.
Osteopontin (OPN) is is a highly phosphorylated sialoprotein that is a prominent component of the mineralized extracellular matrices of bones and teeth. The protein is highly phosphorylated and glycosylated. The nascent protein has a size of 33 kDa; after posttranslational modifications its molecular weight increases to 44 kDa. A non phosphorylated form of OPN is produced by normal rat kidney cells. It is also found in urine, where it inhibits kidney stone formation.
Additionally OPN is expressed by various tissues, such as bone, teeth, endometrial and epithelial tissues, and also macrophages, different types of tumors, T cells and smooth muscle cells. OPN is able to influence bone homeostasis by promoting differentiation of osteoclasts or by enhancing osteoclast activity. OPN protects against apoptosis and induces survival and proliferation in several cell types. OPN is also associated with tumor genesis.
Because of its ability to interact with multiple cell surface receptors, OPN plays a major role in many physiological and pathological pathways including wound healing, tumor genesis, inflammation, bone turnover and immune responses. Therefore the manipulation of plasma OPN levels is useful in the treatment of cancer metastasis, osteoporosis and autoimmune diseases, such as rheumatoid arthritis.