Scarface, a secreted serine protease-like protein, regulates polarized localization of laminin a at the basement membrane of the drosophila embryo

Résumé

Cell-matrix interactions brought about by the activity of Integrins and Laminins maintain the polarized architecture of epithelia and mediate morphogenetic interactions between apposing tissues. Although the polarized localization of Laminins at the basement membrane is a crucial step in these processes, little is known about how this polarized distribution is achieved. Here we analyzed in Drosophila the role of the secreted Serine-Protease like protein Scarface in germ band retraction and dorsal closure, morphogenetic processes that rely on the activity of Integrins and Laminins. We present evidence that scarface is regulated by JNK and that scarface mutant embryos show defects in these morphogenetic processes. Anomalous accumulation of Laminin A on the apical surface of epithelial cells is observed in these embryos and this happened prior to inducing loss of epithelial polarity. We propose that Scarface plays a key role in regulating the polarized localization of Laminin A in this developmental context.