Spp1

Major non-collagenous bone protein that binds tightly to hydroxyapatite. Appears to form an integral part of the mineralized matrix. Probably important to cell-matrix interaction.

Acts as a cytokine involved in enhancing production of interferon-gamma and interleukin-12 and reducing production of interleukin-10 and is essential in the pathway that leads to type I immunity.

Forms covalent cross-links mediated by transglutaminase TGM2, between a glutamine and the epsilon-amino group of a lysine residue, forming homopolymers and heteropolymers, increasing its collagen binding properties.

Extensively phosphorylated by FAM20C in the extracellular medium at multiple sites within the S-x-E/pS motif (PubMed:15869464, PubMed:22582013, PubMed:26091039). The phosphorylated form inhibits hydroxyapatite crystallization. Dephosphorylation via a mechanism involving ALPL/TNAP promotes hydroxyapatite crystallization (By similarity).

O-glycosylated. Isoform 5 is GalNAc O-glycosylated at Thr-59 or Ser-62.

Belongs to the osteopontin family.

Detected in cerebrospinal fluid and urine (at protein level) (PubMed:25326458, PubMed:36213313, PubMed:37453717). Bone. Found in plasma.

• Secreted

BNSP, OPN, PSEC0156, SPP1, Osteopontin, Bone sialoprotein 1, Nephropontin, Secreted phosphoprotein 1, Urinary stone protein, Uropontin, SPP-1

• entrezGene:6696
• omim:166490
• swissprot:P10451

Proteins

Immuno-oncology

• Immunology & Infectious Disease
• Neuroscience
• Oncology

35423Da