| Popis: |
The conserved bazooka (baz/par3) gene acts as a key regulator of asymmetrical cell divisions across the animal kingdom. The associated Par3/Baz-Par6-aPKC protein complex is also well known for its conserved role in the establishment of apical/basal cell polarity in epithelial cells. Here we define a novel, positive function of Baz/Par3 in the Notch pathway. Using Drosophila wing and eye development, we demonstrate that Baz is needed for Notch-signaling activity and in general for correct transcriptional activation of Notch target genes. Baz appears to act independently of aPKC in these contexts, as knockdown of aPKC causes unrelated phenotypes. Our genetic in vivo data suggest that Baz acts the level of active NICD, the cleaved Notch intracellular domain, which upon pathway activation translocates to the nucleus and acts as a transcriptional co-activator. We also demonstrate a biochemical interaction between NICD and Baz. Taken together, our data define a novel role of the polarity protein Baz/Par3, as a positive and direct regulator of Notch signaling through its interaction with NICD. |
