An adhesion molecule in free-living Dictyostelium amoebae with integrin beta features

EMBO Rep. 2006 Jun;7(6):617-21. doi: 10.1038/sj.embor.7400701. Epub 2006 May 12.


The study of free-living amoebae has proven valuable to explain the molecular mechanisms controlling phagocytosis, cell adhesion and motility. In this study, we identified a new adhesion molecule in Dictyostelium amoebae. The SibA (Similar to Integrin Beta) protein is a type I transmembrane protein, and its cytosolic, transmembrane and extracellular domains contain features also found in integrin beta chains. In addition, the conserved cytosolic domain of SibA interacts with talin, a well-characterized partner of mammalian integrins. Finally, genetic inactivation of SIBA affects adhesion to phagocytic particles, as well as cell adhesion and spreading on its substrate. It does not visibly alter the organization of the actin cytoskeleton, cellular migration or multicellular development. Our results indicate that the SibA protein is a Dictyostelium cell adhesion molecule presenting structural and functional similarities to metazoan integrin beta chains. This study sheds light on the molecular mechanisms controlling cell adhesion and their establishment during evolution.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Animals
  • Cell Adhesion
  • Cell Adhesion Molecules / chemistry*
  • Cell Adhesion Molecules / genetics
  • Cell Adhesion Molecules / metabolism*
  • Cell Movement
  • Conserved Sequence
  • Cytosol / metabolism
  • Dictyostelium / genetics
  • Genes, Protozoan
  • Glutathione Transferase / metabolism
  • Integrins / chemistry*
  • Integrins / genetics
  • Integrins / metabolism*
  • Molecular Sequence Data
  • Mutation
  • Protein Sorting Signals
  • Protein Structure, Tertiary
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / metabolism
  • Recombination, Genetic
  • Talin / metabolism


  • Cell Adhesion Molecules
  • Integrins
  • Protein Sorting Signals
  • Recombinant Fusion Proteins
  • Talin
  • Glutathione Transferase