Induction of cyclic AMP-binding proteins by dibutyryl cyclic AMP in mouse neuroblastoma cells

Mouse neuroblastoma cells grown in the presence of 1 mM N⁶, O^2′-dibutyryl-cyclic AMP showed a 3-fold increase in cyclic AMP-binding proteins. The role of dibutyryl cyclic AMP in the introduction of cyclic AMP-binding proteins in these cells has been studied. Induced cyclic AMP-binding proteins were observed in the cytoplasm 15 h after dibutyryl cyclic AMP treatment. The increase in cyclic AMP-binding proteins required RNA and protein synthesis. It is suggested that the 15-h lag occurs at the post-transcriptional and/or translational level. Cyclic AMP-binding proteins are found in both soluble and particulate cell fractions. Dibutyryl cyclic AMP increased binding proteins in both fractions. The control and dibutyryl cyclic AMP-induced binding proteins showed similar affinity for cyclic AMP. The data indicate that dibutyryl cyclic AMP caused the following sequential events: a 12-fold increase in cyclic AMP levels; a 40% increase in phosphodiesterase activity; and a 300% (3-fold) increase in cyclic AMP-binding proteins. It is suggested that the differentiation of mouse neuroblastoma cells involves increased levels of cyclic AMP and cyclic AMP-binding proteins.