Regulation of cell-cell adhesion during Dictyostelium development.

During development of Dictyostelium, four adhesion systems have been identified and adherens junction-like structures have been discovered in the fruiting body. The temporal and spatial expression of cell adhesion molecules (CAMs) is under stringent developmental control, corresponding to major shifts in morphological complexity. Genetic manipulations, including over-expression and knockout mutations, of the adhesion genes, cadA (encoding DdCAD-1), csaA (gp80) and lagC (gp150), have shed light on new roles for cell adhesion molecules in aggregate size regulation, cell-type proportioning, cell differentiation and cell sorting. As cell-cell interactions remain highly dynamic within cell streams and aggregates, mechanisms must exist to facilitate the rapid assembly and disassembly of adhesion complexes. Studies on gp80 have led to a model for the rapid assembly of adhesion complexes via lipid rafts.