Osteopontin Rabbit Polyclonal Antibody

Function

Osteopontin (OPN), also known as bone sialoprotein I (BSP-1 or BNSP), early T-lymphocyte activation (ETA-1), secreted phosphoprotein 1 (SPP1), 2ar and Rickettsia resistance (Ric),[5] is a protein that in humans is encoded by the SPP1 gene (secreted phosphoprotein 1). The murine ortholog is Spp1. Osteopontin is a SIBLING (glycoprotein) that was first identified in 1986 in osteoblasts. The prefix osteo- indicates that the protein is expressed in bone, although it is also expressed in other tissues. The suffix -pontin is derived from "pons," the Latin word for bridge, and signifies osteopontin's role as a linking protein. Osteopontin is an extracellular structural protein and therefore an organic component of bone. Synonyms for this protein include sialoprotein I and 44K BPP (bone phosphoprotein). The gene has 7 exons, spans 5 kilobases in length and in humans it is located on the long arm of chromosome 4 region 22 (4q1322.1). The protein is composed of ~300 amino acids residues and has ~30 carbohydrate residues attached, including 10 sialic acid residues, which are attached to the protein during post-translational modification in the Golgi apparatus. The protein is rich in acidic residues: 30-36% are either aspartic or glutamic acid.

Background References

1. Christensen B., Nielsen M.S., Haselmann K.F., Petersen T.E., Sorensen E.S.;"Post-translationally modified residues of native human osteopontin are located in clusters: identification of 36 phosphorylation and five O-glycosylation sites and their biological implications.";Biochem. J. 390:285-292(2005).

2. Crosby A.H., Edwards S.J., Murray J.C., Dixon M.J.;"Genomic organization of the human osteopontin gene: exclusion of the locus from a causative role in the pathogenesis of dentinogenesis imperfecta type II.";Genomics 27:155-160(1995).

Sequence Similarity

Belongs to the osteopontin family.

Tissue Specificity

Bone. Found in plasma.

Post-translational Modification

Extensively phosphorylated by FAM20C in the extracellular medium at multiple sites within the S-x-E/pS motif.; O-glycosylated. Isoform 5 is GalNAc O-glycosylated at Thr-59 or Ser-62.

Subcellular Location

Secreted.

UNIPROT

SwissProt: P10451 Human

Synonyms