The widely expressed extracellular matrix protein SMOC-2 promotes keratinocyte attachment and migration

Exp Cell Res. 2008 Aug 1;314(13):2477-87. doi: 10.1016/j.yexcr.2008.05.020. Epub 2008 Jun 7.

Abstract

SMOC-2 is a recently discovered member of the BM-40/SPARC/osteonectin family of extracellular multidomain proteins of so far unknown function. While we have shown earlier that the homologous protein SMOC-1 is associated with basement membranes, in this study we demonstrate that, in the mouse, SMOC-2 could be detected in a large number of non-basement membrane localizations, often showing a diffuse tissue distribution. A more distinct expression pattern was seen in skin where SMOC-2 is mainly present in the basal layers of the epidermis. Functionally, recombinant SMOC-2 stimulated attachment of primary epidermal cells as well as several epidermal-derived cell lines but had no effect on the attachment of non-epidermal cells. Inhibition experiments using blocking antibodies against individual integrin subunits allowed the identification of alphavbeta6 and alphavbeta1 integrins as important cellular receptors for SMOC-2. Cell attachment as well as the formation of focal adhesions could be attributed to the extracellular calcium-binding domain. The calcium-binding domain also stimulated migration, but not proliferation of keratinocyte-like HaCaT cells. We conclude that SMOC-2, like other members of the BM40/SPARC family, acts as a regulator of cell-matrix interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Antigens / chemistry
  • Antigens / metabolism
  • Antigens / physiology
  • Calcium-Binding Proteins / chemistry
  • Calcium-Binding Proteins / metabolism
  • Calcium-Binding Proteins / physiology*
  • Cell Adhesion
  • Cell Movement*
  • Cell Proliferation
  • Cells, Cultured
  • Embryo, Mammalian
  • Extracellular Matrix Proteins / chemistry
  • Extracellular Matrix Proteins / metabolism
  • Extracellular Matrix Proteins / physiology
  • Guinea Pigs
  • Humans
  • Keratinocytes / metabolism
  • Keratinocytes / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Protein Structure, Tertiary
  • Recombinant Proteins / metabolism
  • Skin / embryology
  • Skin / metabolism
  • Tissue Distribution

Substances

  • Antigens
  • Calcium-Binding Proteins
  • Extracellular Matrix Proteins
  • Recombinant Proteins
  • SMOC-2 protein, mouse
  • ubiquitous tissue antigen