The coordination of actin filament and microtubule (MT) dynamics is important for axon pathfinding in the developing nervous system. A number of axon guidance cues are known, including netrins and their receptors, but it is unclear whether they regulate MT dynamics directly or indirectly. Guofa Liu and colleagues now (p. 3070) investigate netrin signalling in cultured primary neuron cells isolated from embryonic mice. They show that TUBB3, a neuronal β-tubulin isotype III and the most dynamic tubulin type, directly interacts with the netrin receptor DCC (deleted in colorectal cancer) and that this interaction is induced by netrin-1. DCC and TUBB3 also colocalize to the growth cones of primary neurons. The authors furthermore demonstrate that the interaction between DCC and TUBB3 is dependent on MT dynamics, because treatment with either the MT-stabilizing drug taxol or the MT-destabilizer nocodazole inhibited this association. Importantly, knockdown of TUBB3 resulted in inhibition of netrin-1-induced neurite and commissural axon outgrowth in vitro, and in defects in commissural axon growth projection in vivo in the developing spinal cord of chick embryos. Taken together, these data suggest that TUBB3 interacts directly with DCC and is required for netrin-1-induced axon outgrowth and tuning in the developing nervous system, thus providing a direct link between axon guidance cues and MT dynamics.