Interrelation between Extracellular Adhesion Proteins and Extracellular Matrix in Reaggregation of Dissociated Sponge Cells

Abstract

This chapter discusses the interrelation between extracellular adhesion proteins and extracellular matrix in the reaggregation of dissociated sponge cells. Sponges (Porifera) are considered as genuine Metazoa and are placed at the base of the animal kingdom. The sponge organism is surrounded by the external epithelium (exopinacoderm), the based epithelial surface (basopinacoderm), and the epithelium of the aquiferous canals. The sponges are used for the isolation and purification of the first soluble aggregation factor (AF). The AF is a key molecule in the cell–cell adhesion apparatus. The AF-mediated cell–cell adhesion system of Geodia cydonium is heterophilic and of the third order. Basically two molecules are involved, the AF and the aggregation receptor (AR). The strength of the interaction between these two molecules is controlled in a tuned manner by enzymatic and nonenzymatic processes. The sponges have invented extracellular elements serving as a guiding matrix for an exact positioning of cells. It comprises the fluidsolid phase (lectin-glucoconjugate system) and the solid phase (collagen). © 1988 Academic Press, Inc.