Abstract
Bone sialoprotein (BSP), dentin matrix protein 1 (DMP1), dentin sialophosphoprotein (DSPP), enamelin (ENAM), matrix extracellular phosphoglycoprotein (MEPE), and osteopontin (OPN) are glycophosphoproteins expressed in bones and/or teeth. Direct comparison of their amino acid sequences do not suggest that they belong to a single genetic family, but a detailed analysis of their chromosomal location and gene structure does. Analysis of human brain mRNA by RT-PCR has led to the discovery of two additional exons thereby making it more convincing that MEPE is a member of the SIBLING (Small Integrin-Binding LIgand, N-linked Glycoprotein) family. We propose that the members of this SIBLING family are extended, flexible proteins in solution that can facilitate the formation of a number of different complexes. For example, OPN can bridge complement Factor H to either an RGD-dependent integrin or to CD44 forming a membrane-bound complex that actively suppresses the alternate complement pathway. Two possible mechanisms for inhibiting the lytic pathway of alternate complement are presented.
Original language | English (US) |
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Pages (from-to) | 33-40 |
Number of pages | 8 |
Journal | Connective tissue research |
Volume | 44 |
Issue number | SUPPL. 1 |
DOIs | |
State | Published - 2003 |
Keywords
- Bone sialoprotein
- Complement
- Integrin-binding
- Osteopontin
- SIBLING
ASJC Scopus subject areas
- Rheumatology
- Biochemistry
- Orthopedics and Sports Medicine
- Molecular Biology
- Cell Biology