Description
Osteopontin (OPN) is a secreted glycoprotein that was originally isolated from bone.
OPN is now known as a highly acidic calcium-binding glycosylated phosphoprotein that is secreted by many cell types, including osteoblasts, kidney tubule cells, macrophages, activated T cells, and vascular smooth muscle cells. Both OPN and thrombin are likely to be localized together at the site of injury, inflammation, and angiogenesis and in tumor tissues.
