Linked Life Data

18072945

Source:http://linkedlifedata.com/resource/pubmed/id/18072945

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2008-3-12
pubmed:abstractText
OPN (osteopontin) is a highly phosphorylated glycoprotein present in many tissues and body fluids. In urine, OPN is a potent inhibitor of nucleation, growth and aggregation of calcium oxalate crystals, suggesting that it has a role in the prevention of renal stone formation. The role of OPN in nephrolithiasis is, however, somewhat unclear, as it may also be involved in urinary stone formation, and it has been identified among the major protein components of renal calculi. Most likely, the function of OPN in urine is dependent on the highly anionic character of the protein. Besides a very high content of aspartic and glutamic residues, OPN is subjected to significant PTM (post-translational modification), such as phosphorylation, sulfation and glycosylation, which may function as regulatory switches in promotion or inhibition of mineralization. In the present study, we have characterized the PTMs of intact human urinary OPN and N-terminal fragments thereof. MS analysis showed a mass of 37.7 kDa for the intact protein. Enzymatic dephosphorylation and peptide mass analyses demonstrated that the protein contains approximately eight phosphate groups distributed over 30 potential phosphorylation sites. In addition, one sulfated tyrosine and five O-linked glycosylations were identified in OPN, whereas no N-linked glycans were detected. Peptide mapping and immunoblotting using different monoclonal antibodies showed that the N-terminal fragments present in urine are generated by proteolytic cleavage at Arg(228)-Leu(229) and Tyr(230)-Lys(231).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1470-8728
pubmed:author
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
411
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
53-61
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Post-translational modification and proteolytic processing of urinary osteopontin.
pubmed:affiliation
Protein Chemistry Laboratory, Department of Molecular Biology and Interdisciplinary Nanoscience Center (iNANO), University of Aarhus, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
pubmed:publicationType
Journal Article