Invasive growth: A two-way street for semaphorin signalling

Growing evidence suggests that semaphorins - known to provide directional cues during axon guidance - also provide regulatory signals for cell migration during tissue morphogenesis. During heart development, it is crucial that semaphorins can signal bidirectionally, functioning as both a ligand and a receptor. Through these distinct signalling pathways, semaphorins can provide both 'stop' and 'go' signals for cell motility and invasive growth.