Notch Signalling: The Multitask Manager of Inner Ear Development and Regeneration.

Notch signalling is a major regulator of cell fate decisions and tissue patterning in metazoans. It is best known for its role in lateral inhibition, whereby Notch mediates competitive interactions between cells to limit adoption of a given developmental fate. However, it can also function by lateral induction, a cooperative mode of action that was originally described during the patterning of the Drosophila wing disc and creates boundaries or domains of cells of the same character. In this chapter, we introduce these two signalling modes and explain how they contribute to distinct aspects of the development and regeneration of the vertebrate inner ear, the organ responsible for the perception of sound and head movements. We discuss some of the factors that could influence the context-specific outcomes of Notch signalling in the inner ear and the ongoing efforts to target this pathway for the treatment of hearing loss and vestibular dysfunction.