6533b854fe1ef96bd12af291

RESEARCH PRODUCT

Modulation Theory of Adhesion: Role of the Ectoenzymes Glycosidase and Glycosyltransferase

subject

description

It is amazing, but still plausible, that in all animal systems hitherto studied there is only one basic principle by which cell-cell recognition occurs. From sponges to higher eukaryotes there is only a small number of cell adhesion molecules which are involved in cell-cell adhesion. Specificities and histogenetic patterning are achieved by modulating processes acting on cell adhesion molecules. In sponges (secondary aggregation system) and in other eukaryotes, the activity and function of cell adhesion molecules are assumed to be modulated by enzymatic processes (glycosylation and deglycosylation). Strong evidence from experiments with sponges is available which indicates that modulation can also occur nonenzymatically by reversible interaction of cell adhesion molecules with lectins. The modulation theory requires only a few kinds of adhesion molecules in order to explain specific cell-cell interaction. In contrast, the chemoaffinity theory (Sperry 1963) requires a multiplicity of different adhesion molecules which are pairwise complementary. The data available also disfavor the assumption that cell adhesion takes place via weak forces (Curtis 1967).