Phenotypic modulation in mouse neuroblastoma cells: the case of acetylcholinesterase

Mouse neuroblastoma clone NIE-115 contains two species of acetylcholinesterase (AChE) which sediment at 4S and 11S. The former is predominant in growing cells (70%), whereas the 11S is more abundant in cells with neurites (55--65%). When cell replication is arrested by sodium butyrate, there is an increase in AChE activity but no modification in the proportion of 4S:11S species. Inhibition of protein synthesis by cycloheximide provokes a slow increase in the 11S form and a parallel decrease in 4S. Neurite retraction in presence of colchicine or excess serum does not lead to a concomitant reversion in the high 11S proportion. We postulate that the 11S AChE is formed by a conversion of the 4S and that the shift in the S-value ratio of the enzyme reflects changes in membrane remodeling during neurite extension.