Repository logo

IMP regulates Kuzbanian to control the timing of Notch signalling in Drosophila follicle cells.

Published version



Change log


Fic, Weronika 
Faria, Celia 
St Johnston, Daniel  ORCID logo


The timing of Drosophila egg chamber development is controlled by a germline Delta signal that activates Notch in the follicle cells to induce them to cease proliferation and differentiate. Here, we report that follicle cells lacking the RNA-binding protein IMP go through one extra division owing to a delay in the Delta-dependent S2 cleavage of Notch. The timing of Notch activation has previously been shown to be controlled by cis-inhibition by Delta in the follicle cells, which is relieved when the miRNA pathway represses Delta expression. imp mutants are epistatic to Delta mutants and give an additive phenotype with belle and Dicer-1 mutants, indicating that IMP functions independently of both cis-inhibition and the miRNA pathway. We find that the imp phenotype is rescued by overexpression of Kuzbanian, the metalloprotease that mediates the Notch S2 cleavage. Furthermore, Kuzbanian is not enriched at the apical membrane in imp mutants, accumulating instead in late endosomes. Thus, IMP regulates Notch signalling by controlling the localisation of Kuzbanian to the apical domain, where Notch cleavage occurs, revealing a novel regulatory step in the Notch pathway.



ADAM10 protease, Delta, Drosophila oogenesis, RNA-binding protein, Animals, Cell Division, Cell Polarity, Disintegrins, Drosophila Proteins, Drosophila melanogaster, Epistasis, Genetic, Female, Intracellular Signaling Peptides and Proteins, Membrane Proteins, Metalloendopeptidases, MicroRNAs, Mutation, Ovarian Follicle, RNA-Binding Proteins, Receptors, Notch, Signal Transduction, Time Factors

Journal Title


Conference Name

Journal ISSN


Volume Title



The Company of Biologists
Wellcome Trust (207496/Z/17/Z)
Wellcome Trust (080007/Z/06/Z)
Wellcome Trust (080007/B/06/Z)
Wellcome Trust (203144/Z/16/Z)
Wellcome Trust (092096/Z/10/Z)
Wellcome Trust (078630/Z/05/Z)
Cancer Research Uk (None)
Is derived from: