In the developing cortex, cortical neurons must migrate over long distances to reach the site of their final differentiation. DCX is a cytoplasmic protein which appears to direct neuronal migration by regulating the organization and stability of microtubules. It contains two doublecortin domains, which bind microtubules. In addition, this protein interacts with LIS1, the regulatory gamma subunit of platelet activating factor acetylhydrolase, and this interaction is important to proper microtubule function in the developing cortex. Mutations in the gene encoding DCX are a cause of X-linked lissencephaly.