ISSN:
0192-253X
Keywords:
Cell-cell
;
adhesion molecule
;
cell binding site
;
cell aggregation
;
development
;
Life and Medical Sciences
;
Genetics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
During development of Dictyostelium discoideum, cells acquire EDTA-resistant cell-cell adhesion at the aggregation stage. The EDTA-resistant cell binding activity is associated with a cell surface glycoprotein of Mr 80,000 (gp80), which mediates cell-cell binding via ho-mophilic interaction. Analysis of the structure of gp80 deduced from cDNA sequence reveals the presence of three internally homologous segments in the NH2-terminal domain, which also contains regions with homology to the neural cell adhesion molecule. Secondary structure predictions show an abundance of β-structures and very few α-helices. This is confirmed by circular dichroism measurements. It is likely that the homologous segments are organized into globular structures, extended from the cell surface by a Pro-rich stalk domain. The cell binding activity of gp80 resides within the first globular repeat of the NH2-terminal domain and has been mapped to a 51 amino acid region between Val123 and Leu 173. Synthetic oligopeptides corresponding to sequences within this region have been prepared and assayed for their ability to bind to cell surface gp80. Results lead to identification of the homophilic binding site to an octapeptide sequence within this region. Synthetic peptides containing this octapeptide sequence and univalent antibodies directed against this site block the formation of organized cell streams during aggregation. Although cell aggregates are eventually formed, most fail to undergo further development to give rise to slugs and fruiting bodies, indicating that cell-cell adhesion involving gp80 is an important step in normal morphogenesis.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/dvg.1020110509
Permalink
