Accumulation of palmitoylcarnitine in neuroblastoma NB‐2a cells affects the expression, phosphorylation and localization of B‐50 protein

Accumulation of palmitoylcarnitine inside the neuroblastoma NB-2a cells was observed to promote their differentiation. Exposure of these cells to carnitine resulted in an intensive estrification of this compound with palmitate. Accumulation of palmitoylcarnitine inside the cells coincided with an increase of the B-50 protein. A phorbol ester stimulated phosphorylation of the B-50 protein and of a coprecipitated 78 kDa band was diminished by 50% in the presence of palmitoylcarnitine. A transfer of B-50 to the membranes was observed to occur at increased intracellular palmitoylcarnitine (upon treatment with 1 mM carnitine). A role of palmitoylcarnitine, as a protein kinase C modulator and a store of precursor for the process of palmitoylation has been postulated.