A major feature inDictyosteliumdevelopment is the transition from the unicellular to the multicellular stage, a process brought about by chemotaxis and cell-cell adhesion. Growth-phase cells are weakly cohesive, whereas aggregation-competent cells adhere strongly to each other. In addition, aggregating cells display an ethylenediamine tetraacetic acid (EDTA)-resistant form of adhesion, which is developmentally regulated. Measuring cell-cell adhesion can thus be a simple and convenient method by which to assess the developmental progression of cells, to characterize mutants, and to discriminate between development and functional defects in cell adhesion molecules or membrane-cytoskeletal interactions. A quantitative cell adhesion assay is obviously crucial for identifying novel cell adhesion factors.
