Both LIS1 and DCX proteins appear to be regulators of microtubules. Microtubules are dynamic components of the intracellular cytoskeleton and are important in regulating cell shape and motility. DCX is expressed in the postmitotic neurons and has been shown to interact directly with and increase the stability of microtubules.25- 27 On the other hand, regulation of microtubules by LIS1 appears more complicated. Interestingly, insights into the function of LIS1 came from its homologue in the filamentous fungus, Aspergillus nidulans. In Aspergillus, the LIS1 homologue, nudF, is involved in translocation of the nucleus through pathways involving other nuclear migration proteins, such as nudE. Translocation of the nucleus is necessary for a neuron to migrate, and a remarkably similar biochemical pathway appears to be present in migrating neurons. In mammals, mNudE, a homologue of nudE, interacts with LIS1, and defects in central nervous system lamination were observed when this interaction was disrupted in Xenopus embryos.28 The function of mNudE appears to involve regulation of the microtubule organizing center, and it may act as a link between LIS1 and α-tubulin, which plays a key role in initiating microtubule polymerization at the microtubule organizing center.