The communication and mutual influence of epithelia and migratory cells is a field of high scientific and medical relevance. Many cellular processes underlying the establishment of cell polarity and adhesion are implicated in migratory cell movement including metastasis in cancer.Primordial germ cells (PGCs) prematurely cross the epithelial barrier of the somatic blastoderm during its cellularization in Drosophila mutants of the aeneas (aen) gene. The objective of this work was the characterization of the biological and molecular function of the Aen protein.In this thesis I show that Aen is required in the somatic cells for the integrity of the blastoderm epithelium. Aen co-localizes with secretory vesicles and with proteins of the dynactin complex required for vesicular transport. Biochemical interaction experiments as well as coimmunoprecipitation experiments reveal that Aen interacts with Arp1, an important component of the dynactin complex, suggesting a function of Aen during secretory vesicle transport. Furthermore Aen interacts biochemically and functionally with Slow as molasses, which is required for blastoderm cellularization and guided PGC migration.In summary, the results suggest that Aen encodes a novel conserved adaptor of the Dynactin complex, required for Slow as molasses (Slam) transport or function in a process essential for the epithelial integrity that consequentially inhibits PGC mismigration. Therefore the aen mutation opens new ways to address important questions on tissue invasion by migratory cells.