THE GANGLIOSIDE GM1 ENHANCES MICROTUBULE NETWORKS AND CHANGES THE MORPHOLOGY OF NEURO-2A CELLS IN-VITRO BY ALTERING THE DISTRIBUTION OF MAP2

The effect of ganglioside GM1 on components of the neuronal cytoskelet on was studied in Neuro-2a neuroblastoma cells using immunofluorescent , immunogold-labeled, and Western blot analysis. Exposure of cells to GM1 for 24 h resulted in an increased microtubular network. and level of tubulin, a redistribution of MAPS immunoreactivity from perikarya t o distal neuritic processes, and an increased MAP2 gold label in the s ubplasmalemmal cytoplasm, neuritic spines, and growth cones. A similar change in the distribution of actin-positive fluorescent immunoreacti vity was observed. In contrast to the redistribution of MAP2, immunolo calization of MAP5 and tau did not change following 24 h GM1 exposure. Our results suggest that gangliosides enhance neuritogenesis by selec tively altering the distribution of MAP2 from perikaryon to neuritic s pines. Furthermore, the enhanced presence of MAP2 in regions known to be rich in microfilaments following GM1 treatment suggests that an int eraction of MAP2 with microfilaments may be necessary for early neurit e formation. (C) 1996 Academic Press, Inc.