Osteopontin (OPN), also known as secreted phosphoprotein 1 (SPP1) and early T lymphocytes activation 1 (ETA-1). OPN contains at its NH2-terminal, the RGD tripeptide sequence that can be bound by RGD-dependent integrins. OPN interacts with α9β1 and α4β1 integrins through a cryptic site of sequence SVVYGLR adjacent to the RGD motif. OPN interacts with integrins and CD44 as receptors. This protein has been shown to play roles in cell migration and survival, bone remodeling, regulation of immune cell functions, apoptosis, control of tumor cell phenotypes, and autoimmune diseases. OPN is involved in recruiting and stimulating macrophages and lymphocytes in response to microbial infections. Several inflammatory cytokines can induce OPN production, including TNF-α, IL-1β and IL-6. In OPN deficient mice, IFN-γ and IL-12 production were decreased, but IL-10 level was elevated, indicating that OPN might modulate cytokine production and promote type I immunity. The OPN receptor-ligand interaction mediates chemotaxis or attachment that depends on whether the protein is in soluble or immobilized form. OPN has also been shown to play a role in the progression of cancer, which is supported by the finding that patients who suffer from disseminated carcinoma also have increased levels of OPN in their plasma. In addition, OPN is a component of the human atherosclerotic plaque and may be a mediator of arterial neointima formation. It is synthesized by macrophage, smooth muscle, and endothelial cells in primary and recurrent human coronary atherosclerotic plaques, which may contribute to the cellular accumulations and dystrophic calcification in the atherosclerotic plaques. OPN is also a substrate for MMP-3, MMP-7, MMP-9, MMP-12, and thrombin within the SVVYGLR motif.
Size
500 μg
Concentration
n/a
Applications
BA
Other Names
Secreted phosphoprotein 1 (SPP1, SPP-1), BNSP, Bone sialoprotein I (BSPI), Early T lymphocyte activation 1 protein (ETA1, ETA-1), OPN, OP