|Ref Sequence Id||NP_776612.1|
|Amino Acid Lenth||278|
|Protein Existence Status||Reviewed: Experimental evidence at protein level|
|Presence in other biological fluids/tissue/cells||blood, urine, seminal fluid|
|Protein Function||Inhibition of ectopic calcification, bone remodelling, cancer metastasis and immune modulatory functions; act as an opsonin, as it binds directly to several bacterial strains leading to enhanced phagocytosis by macrophages; can induce Th1 type immunity by inducing interleukin-12 expression in macrophages|
|Biochemical Properties||resistant to proteolysis by neonatal gastric juice;very resistant to harsh conditions; e.g., heat treatment at 90 C has no effect on the post-translational modifications decorating the protein;Proteolytic cleavage close to the integrin binding motifs has been demonstrated to increase the integrin binding properties of OPN; Milk OPN is a very acidic protein due to a high degree of negatively charged amino acids and the many phosphorylations decorating the protein;|
|Significance in milk||OPN plays a role in the development of the infant and could provide an important immunological signal during development; OPN, which possess known cytokine-like properties, was the most abundantly expressed when compared with the expression of 240 cytokine related genes in human milk; involved in mammary gland development and differentiation; bind and form soluble complexes with calcium ions which together with especially the caseins, could inhibit unintentional precipitation of amorphous calcium phosphate in milk; act as a transporter of these immunomodulating and antimicrobial proteins to their site of action and to protect them from proteolysis|
|PTMs||Phosphorylated glycoprotein; ~25 phosphates distributed over 36 potential sites in human milk osteopontin; ~22 phosphates distributed over 28 potential sites in bovine milk osteopontin; Bovine milk OPN contains three O-glycosylated threonine residues close to the integrin binding motifs; The glycan structures on human milk OPN have been shown to consist of large fucosylated N-acetyllactosamine units; the carbohydrates on bovine OPN consist of a disialylated GalNAc-galactose cores|
| Site(s) of PTM(s) |
|>sp|P31096|OSTP_BOVIN Osteopontin OS=Bos taurus OX=9913 GN=SPP1 PE=1 SV=2|
MRIAVICFCL LGIASALPVK PT S*23S*24GS*26S*27EEK QLNNKYPDAV ATWLKPDPSQ KQTFLAPQN S*60VS*62S*63EETDDNK QNTLP S*76KS*78NES*81PEQTDDLDD DDDNS*95QDVN S*100NDS*103DDAETTDDPDHS*115DESHHS*121DES*124DEVDFPT*131DIPTIAVFT*140 PFIPT*145ESANDGRGDSVAYGLKSRSKKFRRSNVQSPDAT*178EE DFTS*184HIES*188EE MHDAPKKTSQLTDHS*205KETNS*210 SELSKELTPK AKDKNKHSNL IES*233QENSKLS*240 QEFHS*245LEDKLDLDHKS*256EEDK HLKIRIS*267HEL DS*272AS*274SEVN
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