Six genes expressed in bones and teeth encode the current members of the SIBLING family of proteins

Larry W. Fisher, Neal S. Fedarko

Research output: Contribution to journalArticlepeer-review

350 Scopus citations


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 languageEnglish (US)
Pages (from-to)33-40
Number of pages8
JournalConnective tissue research
Issue numberSUPPL. 1
StatePublished - 2003


  • Bone sialoprotein
  • Complement
  • Integrin-binding
  • Osteopontin

ASJC Scopus subject areas

  • Rheumatology
  • Biochemistry
  • Orthopedics and Sports Medicine
  • Molecular Biology
  • Cell Biology


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