Gangliosides have been implicated in numerous cellular functions in the developing nervous system. The expression of 9-O-acetyl gangliosides recognized by the JONES mAb correlates with periods of cell migration and axonal pathfinding. In vitro, addition of JONES induces growth cone collapse of dorsal root ganglion neurons. This suggests a modulatory activity of 9-O-acetyl gangliosides on growth cone motility and/or adhesion. In this study we have investigated the effect of JONES mAb addition on the cytoskeleton of dorsal root ganglion neurons in vitro. We have shown that blockage of 9-O-acetyl gangliosides induces the appearance of lateral spikes along the neurites in addition to the effect on the growth cone. Microfilament and microtubular rearrangements accompany these structural modifications. We present evidence that the main effect of JONES mAb is to induce microtubule depolymerization both in growth cones and neurites. Together with the analysis on the spatial distribution of these gangliosides along the cell surface, our results suggest that 9-O-acetyl gangliosides recognized by JONES mAb might serve a concerted action, modulating growth cone motility and axonal branch formation.