van Bergeijk, P. et al. Nature 518, 111–114 (2015).

The function of organelles such as the endoplasmic reticulum is tightly linked to their position, but positioning at defined sites may not be necessary for other organelles. van Bergeijk et al. present a method to localize organelles in a light-dependent fashion, making it possible to address the function and requirement of organelle positioning. The researchers adapted the TULIP (tunable, light-controlled interacting protein tags) system to recruit peroxisomes, mitochondria or endosomes to molecular motors such as kinesin, dynein or myosin. This allowed them to target these organelles to the cell periphery, cell center or dendritic spines. Using this approach, the researchers demonstrated a role for endosomes in the regulation of growth-cone dynamics.