Phosphorylation of lymphocyte nuclear acidic proteins: regulation by cyclic nucleotides.

Guanosine 3',5'-monophosphate (cyclic GMP) and cholinergic agents stimulate incorporation of phosphate into specific nuclear acidic proteins of horse peripheral blood lymphocytes. Agents that raise intracellular adenosine 3',5'-monophosphate (cyclic AMP) inhibit nuclear acidic protein phosphorylation. The opposing effects of cyclic GMP and cyclic AMP upon nuclear protein phosphorylation parallel the effects of the cyclic nucleotides upon induction of lymphocyte proliferation.