Neuregulin (NRG) is a crucial regulator of oligodendrocyte development, strongly promoting both the proliferation of oligodendrocyte precursor cells and the survival and maturation of oligodendrocytes. How can the same growth factor mediate such different effects? New work in this issue of Nature Cell Biology implicates an integrin-mediated switch in signalling that results in the loss of the proliferative response and the enhancement of survival and maturation.