Neuronal polarity: microtubules strike back

Specification of one neurite as the axon is the first milestone achieved as neuronal polarity is established. It is clear that regional changes in the cytoskeleton underlie axonal differentiation, but is one cytoskeletal element any more crucial than the others? Although early studies implicated microtubules, more recent studies have focused on the actin cytoskeleton as the potential hub for factors that influence axonal differentiation. Now, studies on a novel protein called CRMP-2 have shifted attention back to microtubules.