In many laboratories, the requirement of microtubule-associated proteins (MAPs) and the stabilization of microtubules for the elongation of neurites has been intensively investigated, with controversial results being obtained. We have observed that the neurite microtubules of (CAD) cells, a mouse brain derived cell, are highly dynamic structures, and so we analyzed several aspects of the cytoskeleton to investigate the molecu-lar causes of this phenomenon.