Par3 cooperates with Sanpodo in the assembly of Notch clusters after asymmetric division of Drosophila sensory organ precursor cells.
This study reveals a novel Notch receptor-containing signaling node organized by Sanpodo and Par3 that is involved in cell fate decisions in the Drosophila peripheral nervous system. These Notch clusters are modulated by components of the Notch signaling pathway, and it is proposed to enhance Notch signaling by focusing ligands and receptors. These results are highly relevant to different areas of biology, including membrane biology, cytokinesis, PAR polarity, Notch signaling, and cell fate decision making.
In multiple cell lines, Delta-Notch signaling regulates cell fate decisions due to unidirectional signaling between daughter cells. In the Drosophila pupal sensory organ lineage, Notch regulates the intra-linear decision on pIIa/pIIb fate to cytokinesis. Notch and Delta, which localize apically and basally at the pIIa-pIIb interface, are expressed at low levels and have a residence time at the plasma membrane of minutes. How Delta can effectively interact with Notch to trigger signaling from a large area of the plasma membrane remains poorly understood. Here, we report that the signaling interface has a unique apico-basal polarity with Par3/Bazooka localized as nano-clusters at the apical and basal level. Notch is preferentially targeted to the pIIa-pIIb interface, where it clusters with Bazooka and its cofactor Sanpodo. Clusters whose assembly relies on the activities of Bazooka and Sanpodo are also positive for Neuralized, the E3 ligase required for Delta activity. We propose that the nano-clusters act as snaps at the novel pIIa-pIIb interface to enable efficient intra-lineage signaling.
Team Dynamics and Mechanics of Epithelia, IGDR