Membrane-bound choline acetyltransferase is a cell surface marker of the differentiated NS-20Y cholinergic cell line.

When differentiated cells of the cholinergic NS-20Y type were incubated with an antiserum to choline acetyltransferase (ChAT), in the presence of complement, immunolysis occurred as demonstrated by release of 20% of total lactate dehydrogenase and 70% of total ChAT. No significant immunolytic effects were observed when either undifferentiated (dividing or non-dividing) or partially differentiated cells were incubated under identical conditions. When the Triton X-114 phase separation technique was employed using membranes from differentiated cells, a small but significant proportion of choline acetyltransferase was recovered in the detergent-rich phase. These results suggest that a membrane-bound form of ChAT is a surface marker of the NS-20Y cell line.