SOCS2 is capable of inhibiting cytokine signalling by interleukin-6 (IL-6) and growth hormone. SOCS2 interacts with the phosphorylated insulin-like growth factor (IGF-I) receptor, where it may play a regulatory role in cellular growth, differentiation, and inhibition of apoptosis via the Ras and PI3K signalling pathways. In humans, SOCS2 mRNA is expressed widely in both foetal and adult tissues, including foetal kidney and adult heart, skeletal muscle, pancreas, and liver. In rats, SOCS2 mRNA exhibits high levels of expression in liver and heart, and in the mouse nervous system, SOCS2 is expressed exclusively by neurons, where it is switched on developmentally in concordance with neuronal differentiation.