Letunic et al. (2017) Nucleic Acids Res doi: 10.1093/nar/gkx922
Letunic et al. (2020) Nucleic Acids Res doi: 10.1093/nar/gkaa937

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OSTEO Osteopontin

SMART accession number:	SM00017
Description:	Osteopontin is an acidic phosphorylated glycoprotein of about 40 Kd which is abundant in the mineral matrix of bones and which binds tightly to hydroxyapatite [1,2,3]. It is suggested that osteopontin might function as a cell attachment factor and could play a key role in the adhesion of osteoclasts to the mineral matrix of bone
Interpro abstract (IPR002038):	The major event of endochondrial ossification is the proteolytic degradation of calcified cartilage and the extracellular matrix, and their substitution with bone-specific extracellular matrix produced and organised by osteoblasts [ (PUBMED:2033080) ]. One of the most abundant products of osteoblasts is osteopontin, a glycosylated phosphoprotein with a high acidic amino acid content and one copy of the cell attachment sequence RGD [ (PUBMED:2033080) ]. It is thought that osteopontin may act as a bridge between osteoblasts and the apatite mineral of the bone [ (PUBMED:2033080) ]. Osteopontin-K is a kidney protein, similar to osteopontin and probably also involved in cell adhesion [ (PUBMED:1414488) ].
GO process:	cell adhesion (GO:0007155), ossification (GO:0001503)
Family alignment:	View or CHROMA formatHMM/Web logoCLUSTALW formatMSF formatFASTA formatPIR format

There are 184 OSTEO domains in 184 proteins in SMART's nrdb database.

Click on the following links for more information.

• Evolution (species in which this domain is found)

• Taxonomic distribution of proteins containing OSTEO domain.

  This tree includes only several representative species. The complete taxonomic breakdown of all proteins with OSTEO domain is also avaliable.

  Click on the protein counts, or double click on taxonomic names to display all proteins containing OSTEO domain in the selected taxonomic class.

• Literature (relevant references for this domain)

• Primary literature is listed below; Automatically-derived, secondary literature is also avaliable.

  • Castagnola P, Bet P, Quarto R, Gennari M, Cancedda R
  • cDNA cloning and gene expression of chicken osteopontin. Expression of osteopontin mRNA in chondrocytes is enhanced by trypsin treatment of cells.
  • J Biol Chem. 1991; 266: 9944-9
  • Display abstract

  • A cDNA clone, pCP15, specific for the chicken 66-kDa major bone phosphoprotein (osteopontin), was isolated from a subtracted library enriched in DNAs coding for mRNAs expressed in chicken differentiating chondrocytes. Northern blot analysis of RNAs extracted from several chick embryo tissues and organs, confirm and extend the observation that osteopontin mRNA expression is not restricted to tissues involved in phosphate metabolism. Osteopontin mRNA was detected in sternal resting chondrocytes at higher levels than in hypertrophic chondrocytes; therefore osteopontin gene transcription occurs in chondrocytes at many stages of differentiation. The steady state level of osteopontin mRNA was enhanced by trypsin treatment of cultured cells. An increased level of osteopontin mRNA in quail chondrocytes constitutively expressing v-myc oncogene is also shown.

• Metabolism (metabolic pathways involving proteins which contain this domain)

• % proteins involved KEGG pathway ID Description 33.33 map04512 ECM-receptor interaction 33.33 map04510 Focal adhesion 33.33 map04620 Toll-like receptor signaling pathway This information is based on mapping of SMART genomic protein database to KEGG orthologous groups. Percentage points are related to the number of proteins with OSTEO domain which could be assigned to a KEGG orthologous group, and not all proteins containing OSTEO domain. Please note that proteins can be included in multiple pathways, ie. the numbers above will not always add up to 100%.

• Links (links to other resources describing this domain)

• INTERPRO	IPR002038

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