Roles of Tsp66E and Tsp74F in border cell migration and the maintenance of border cell adhesion in Drosophila

Abstract

KAI1/CD82, a member of the tetraspanin superfamily, is a tumor metastasis suppressor implicated in cell migration and adhesion in various tumor cells. Drosophila expresses an orthologue of KAI1/CD82, Tsp66E. However, the role of Tsp66E in cell migration and adhesion has not been studied. Here, we investigated the roles of Tsp66E in border cell migration and border cell adhesion, which are well-established in vivo models of cell migration and adhesion. Border cell migration was accelerated by loss of Tsp66E but delayed by Tsp66E overexpression. Deficiency of Tsp74F, a Drosophila orthologue of human Tspan11 and CD151, further increased the migration rate of Tsp66E mutant border cells. In addition, the premature detachment of border cells at stage 8 oogenesis induced by the loss of inflated, which encodes αPS2 integrin, was enhanced by Tsp66E deficiency. Interestingly, Tsp74F deficiency further enhanced the phenotype. αPS2 and βPS integrins were highly expressed in anterior follicle cells before border cell migration, consistent with an important role in border cell adhesion. The results suggest that Tsp66E and Tsp74F cooperate to negatively regulate border cell migration, support the integrin-mediated maintenance of border cell adhesion, and prevent premature migration.