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Cell-cell adhesion and morphogenesis in Dictyostelium discoideum
1Banting and Best Department of Medical Research, Charles H. Best Institute, University of Toronto, Ontario, Canada.
Developmental Genetics
|January 1, 1990
Summary
Cell-cell adhesion in Dictyostelium discoideum development is mediated by glycoprotein 80 (gp80). Researchers identified a specific octapeptide sequence within gp80 responsible for homophilic binding, crucial for normal development.
Area of Science:
- Cell Biology
- Developmental Biology
- Biochemistry
Background:
- Dictyostelium discoideum cells develop EDTA-resistant cell-cell adhesion during aggregation.
- This adhesion is mediated by an 80,000 Mr cell surface glycoprotein (gp80) through homophilic interactions.
Purpose of the Study:
- To elucidate the structural basis of gp80-mediated cell-cell adhesion.
- To identify the specific binding site within gp80 responsible for homophilic interaction.
Main Methods:
- cDNA sequence analysis to deduce gp80 structure.
- Secondary structure prediction and circular dichroism measurements.
- Synthesis and assay of oligopeptides to map the binding site.
Main Results:
- gp80 possesses three homologous segments in its NH2-terminal domain, with homology to neural cell adhesion molecules.
- The cell-binding activity is localized to a 51 amino acid region within the first globular repeat.
- An octapeptide sequence within this region was identified as the homophilic binding site.
Conclusions:
- The homophilic binding site of gp80 has been precisely mapped to an octapeptide sequence.
- Disruption of this binding site using synthetic peptides or antibodies impairs cell stream formation and subsequent development.
- gp80-mediated cell-cell adhesion is essential for normal Dictyostelium morphogenesis.