Phosphorylation of chromosomal and ribosomal proteins and intracellular levels of cyclic 3′,5′-adenosine monophosphate and cyclic 3′,5′-guanosine monophosphate during amino acid starvation in Landschutz tumour cells

Short-term amino acid starvation of Landschutz tumour cells incubated in vitro leads to an increased phosphorylation of nuclear acidic proteins but has very little effect on histone phosphorylation while the phosphorylation of ribosomal proteins is depressed. These effects are not secondary to a variation of the phosphate donor pool. The intracellular accumulation of cAMP is not significantly affected during amino acid starvation but cGMP levels are decreased.