Locomotory competence and laminin-specific cell surface binding sites are lost during myoblast differentiation

The specific interaction of embryonal cells with the extracellular matrix (ECM) is one of the principal forces influencing embryonal development (Hay, 1984; Trinkaus, 1984). We used a muscle satellite cell line (MM14dy) to determine the relationship between locomotory response to laminin and the expression of specific cell surface binding sites for it. Time lapse videomicroscopic analysis was used to study the locomotory response and radioligand binding assays and cell attachment assays were used to follow the expression levels of binding sites for laminin and its subfragments E8 and E1-4. We report here the novel finding that the ability of MM14dy to locomote over laminin diminishes and finally vanishes as the cells differentiate. The simultaneous drop in expression of binding sites for laminin is interpreted as being of potential significance during development and repair.