Figure 1. A hypothesis for the role of reduction of GSK3β in development of aging phenotype in the liver. GSK3β triggers degradation of cyclin D3 in livers of young mice. The age-associated decline of growth hormone and GSK3β leads to the stabilization of cyclin D3 and to formation of transcriptional repressor C/EBPα-Brm and translational activator CUGBP1-eIF2 complexes. We suggest that the appearance of these two comp-lexes in the liver might change global transcription and translation leading to the development of aging phenotype in the liver.