Expression of SIBLINGs and their partner MMPs in salivary glands.
Three members of the SIBLING family of integrin-binding phosphoglycoproteins (bone sialoprotein, BSP; osteopontin, OPN; and dentin matrix protein-1, DMP1) were recently shown to bind with high affinity (nM) and to activate 3 different matrix metalloproteinases (MMP-2, MMP-3, and MMP-9, respectively) in vitro. The current study was designed to document the possible biological relevance of the SIBLING-MMP activation pathway in vivo by showing that these 3 SIBLINGs and their known MMP partners are co-expressed in normal adult tissue. BSP, OPN, and DMP1 were invariably co-expressed with their partner MMPs in salivary glands of humans and mice. The 2 SIBLING proteins without known MMP partners, dentin sialophosphoprotein (DSPP) and matrix extracellular phosphoglycoprotein (MEPE), were also expressed in salivary glands. Expression of all SIBLINGs in this normal, non-mineralizing epithelial tissue suggests that they serve at least one function in vivo other than directly promoting matrix mineralization--a function we hypothesize involves local activation of MMPs.
Craniofacial and Skeletal Diseases Branch, Building 30, Room 228, National Institute of Dental and Craniofacial Research, National Institutes of Health, DHHS, 9000 Rockville Pike, Bethesda, MD 20892-4320, USA.
K U E
KU
Ogbureke
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LW
Fisher
D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal; D002448:Cell Adhesion; D016326:Extracellular Matrix Proteins / Q000032:analysis*; D006023:Glycoproteins / Q000032:analysis; D006801:Humans; D007124:Immunoenzyme Techniques; D058574:Integrin-Binding Sialoprotein; D020778:Matrix Metalloproteinase 2 / Q000032:analysis; D019278:Matrix Metalloproteinase 3 / Q000032:analysis; D020780:Matrix Metalloproteinase 9 / Q000032:analysis; D020782:Matrix Metalloproteinases / Q000032:analysis*; D051379:Mice; D053495:Osteopontin; D010750:Phosphoproteins / Q000032:analysis*; D011498:Protein Precursors / Q000032:analysis; D011506:Proteins / Q000032:analysis*; D018987:Salivary Ducts / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D012469:Salivary Glands / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D012795:Sialoglycoproteins / Q000032:analysis*; D014157:Transcription Factors; D000099311:Dentin Sialophosphoprotein
D000911:Antibodies, Monoclonal; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D058574:Integrin-Binding Sialoprotein; D020778:Matrix Metalloproteinase 2; D019278:Matrix Metalloproteinase 3; D020780:Matrix Metalloproteinase 9; D020782:Matrix Metalloproteinases; D053495:Osteopontin; D010750:Phosphoproteins; D011498:Protein Precursors; D011506:Proteins; D012795:Sialoglycoproteins; D014157:Transcription Factors; D000099311:Dentin Sialophosphoprotein; C513309:DMP1 protein, human; C513308:Dmp1 protein, mouse; C102116:Dmtf1 protein, mouse; C546871:IBSP protein, human; C546872:Ibsp protein, mouse; C546873:Ibsp protein, rat; C486579:MEPE protein, human; C506895:SPP1 protein, human; C506896:Spp1 protein, mouse; C506897:Spp1 protein, rat