Secreted Phosphoprotein 1 (Osteopontin, Bone Sialoprotein I, Early T-Lymphocyte Activation 1), Osteopontin/Immunoglobulin Alpha 1 Heavy Chain Constant Region Fusion Protein, Secreted Phosphoprotein 1 Variant 6, SPP1/CALPHA1 Fusion, ETA-1, BSPI, SPP-1, Bone sialoprotein 1, BNSP, Urinary stone protein, PSEC0156, OPN, Uropontin, SPP1, Secreted Phosphoprotein 1, Early T-Lymphocyte Activation 1, Nephropontin, Osteopontin, Bone Sialoprotein I


Osteopontin (OPN), also known as bone sialoprotein I (BSP-1 or BNSP), secreted phosphoprotein 1 (SPP1), is a protein that in humans is encoded by the SPP1 gene. OPN binds tightly to hydroxyapatite and appears probably important to cell-matrix interaction. OPN 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.

KO Status

RenMab: Antibody Discovery

Drug Information

Drug Name





Clinical Trials

Osteopontins (Merck Serono)


Merck Serono

Nervous System Diseases


2K-1, ASK-8007


Immuno-Biological Laboratories

Arthritis, Rheumatoid, Bone Diseases, Autoimmune Diseases





LC-MS/MS characterization of O-glycosylation sites and glycan structures of human cerebrospinal fluid glycoproteins

Halim A., Ruetschi U., Larson G., Nilsson J.,

J. Proteome Res. 12:573-584(2013)

An enzyme assisted RP-RPLC approach for in-depth analysis of human liver phosphoproteome

Bian Y., Song C., Cheng K., Dong M., Wang F., Huang J., Sun D., Wang L., Ye M., Zou H.,

J. Proteomics 96:253-262(2014)

A single kinase generates the majority of the secreted phosphoproteome

Tagliabracci V.S., Wiley S.E., Guo X., Kinch L.N., Durrant E., Wen J., Xiao J., Cui J., Nguyen K.B., Engel J.L., Coon J.J., Grishin N., Pinna L.A., Pagliarini D.J., Dixon J.E.,

Cell 161:1619-1632(2015)

cDNA cloning, mRNA distribution and heterogeneity, chromosomal location, and RFLP analysis of human osteopontin (OPN)

Young M.F., Kerr J.M., Termine J.D., Wewer U.M., Wang M.G., McBride O.W., Fisher L.W.,

Genomics 7:491-502(1990)

Inhibition of calcium oxalate crystal growth in vitro by uropontin: another member of the aspartic acid-rich protein superfamily

Shiraga H., Min W., VanDusen W.J., Clayman M.D., Miner D., Terrell C.H., Sherbotie J.R., Foreman J.W., Przysiecki C., Neilson E.G., Hoyer J.R.,

Proc. Natl. Acad. Sci. U.S.A. 89:426-430(1992)

Genomic organization of the human osteopontin gene: exclusion of the locus from a causative role in the pathogenesis of dentinogenesis imperfecta type II

Crosby A.H., Edwards S.J., Murray J.C., Dixon M.J.,

Genomics 27:155-160(1995)

Cloning and characterization of the human osteopontin gene and its promoter

Hijiya N., Setoguchi M., Matsuura K., Higuchi Y., Akizuki S., Yamamoto S.,

Biochem. J. 303:255-262(1994)

Expression of osteopontin in human glioma. Its correlation with the malignancy

Saitoh Y., Kuratsu J., Takeshima H., Yamamoto S., Ushio Y.,

Lab. Invest. 72:55-63(1995)

Complete sequencing and characterization of 21,243 full-length human cDNAs

Ota T., Suzuki Y., Nishikawa T., Otsuki T., Sugiyama T., Irie R., Wakamatsu A., Hayashi K., Sato H., Nagai K., Kimura K., Makita H., Sekine M., Obayashi M., Nishi T., Shibahara T., Tanaka T., Ishii S., Sugano S.,

Nat. Genet. 36:40-45(2004)

Signal sequence and keyword trap in silico for selection of full-length human cDNAs encoding secretion or membrane proteins from oligo-capped cDNA libraries

Otsuki T., Ota T., Nishikawa T., Hayashi K., Suzuki Y., Yamamoto J., Wakamatsu A., Kimura K., Sakamoto K., Hatano N., Kawai Y., Ishii S., Saito K., Kojima S., Sugiyama T., Ono T., Okano K., Yoshikawa Y., Isogai T.,

DNA Res. 12:117-126(2005)