Renal expression of SIBLING proteins and their partner matrix metalloproteinases (MMPs).
BACKGROUND
Three members of the small integrin-binding ligand N-linked glycoprotein (SIBLING) family of proteins have recently been shown to bind and activate specific promatrix metalloproteinases (MMPs) and to overcome the inhibition of tissue inhibitors of MMPs (TIMPs). Although usually associated with mineralized tissues, we have shown that the SIBLINGs and their MMP partners, when known, are coexpressed in salivary gland ductal cells. The present study examined the expression patterns of both the SIBLINGs and their MMP partners in adult kidney.


METHODS
The expression patterns of all five SIBLINGs known to date, and their MMP partners were determined in monkey kidney using immunohistochemistry and in situ hybridization techniques.


RESULTS
Bone sialoprotein (BSP) and its partner, MMP-2, were coexpressed in both the proximal and distal tubules. Osteopontin, as previously shown, was expressed in the distal tubules while its partner MMP-3 was expressed in both the proximal tubule and distal tubles. Dentin matrix protein-1 (DMP1) and MMP-9 were coexpressed throughout the nephron, including both parietal cells of Bowman's capsule and the thin limb of the loop of Henle. Dentin sialophosphoprotein (DSPP) and matrix extracellular phosphoglycoprotein (MEPE) were expressed in the proximal tubule and distal tubule, and proximal tubule, respectively.


CONCLUSIONS
In contrast to salivary gland in which all SIBLINGs and their MMP partners were coexpressed throughout the length of the ducts, these proteins were differentially expressed within the normal adult nephron. We hypothesize that the cells use the SIBLING/MMP pairs in the normal turnover of cell surface proteins and/or pericellular matrix proteins such as those in basement membranes.
Ogbureke
Kalu U E
KU
Matrix Biochemistry Section, Craniofacial and Skeletal Disease Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, DHHS, Bethesda, Maryland 20982-4320, USA.
Fisher
Larry W
LW
D000818:Animals; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D006023:Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D058574:Integrin-Binding Sialoprotein; D016023:Integrins / Q000378:metabolism; D007668:Kidney / Q000502:physiology*; D008252:Macaca fascicularis; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D019278:Matrix Metalloproteinase 3 / Q000235:genetics / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D020782:Matrix Metalloproteinases / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D053495:Osteopontin; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000235:genetics / Q000378:metabolism; D000099311:Dentin Sialophosphoprotein
D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D058574:Integrin-Binding Sialoprotein; D016023:Integrins; D020778:Matrix Metalloproteinase 2; D019278:Matrix Metalloproteinase 3; D020780:Matrix Metalloproteinase 9; D020782:Matrix Metalloproteinases; D053495:Osteopontin; D010750:Phosphoproteins; D011498:Protein Precursors; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein; C513309:DMP1 protein, human; C513308:Dmp1 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