Sara endosomes and the asymmetric division of intestinal stem cells.

Tissue homeostasis is maintained by adult stem cells, which self-renew and give rise to differentiating cells. The generation of daughter cells with different fates is mediated by signalling molecules coming from an external niche or being asymmetrically dispatched between the two daughters upon stem cell mitosis. In the adult Drosophila midgut, the intestinal stem cell (ISC) divides to generate a new ISC and an enteroblast (EB) differentiating daughter.

Wingless modulates the ligand independent traffic of Notch through Dishevelled.

Here we investigate the structural and functional basis of the interactions between Notch and Wingless signalling in Drosophila. Using yeast-two-hybrid and pull-down assays we show that Notch can bind directly a form of Dishevelled that is stabilized upon Wingless signalling. Moreover, we show that the mechanism by which Wingless signalling is able to downregulate Notch is by promoting its ligand-independent traffic to a compartment where it is degraded and that this activity depends on Dishevelled.