Gas1 Is Related to the Glial Cell-derived Neurotrophic Factor Family Receptors α and Regulates Ret Signaling

Abstract

The growth arrest-specific gene 1 (Gas1) protein has been proposed to function during development as an inhibitor of growth and a mediator of cell death and is also re-expressed in adult neurons during excitotoxic insult. Here we have demonstrated that the Gas1 protein shows high structural similarity to the glial cell-derived neurotrophic factor (GDNF) family receptors α, which mediate GDNF responses through the receptor tyrosine kinase Ret. We found that Gas1 binds Ret in a ligand-independent manner and sequesters Ret in lipid rafts. Signaling downstream of Ret is thus modified through a mechanism that involves the adaptor protein Shc as well as ERK, eventually blocking Akt activation. Consequently, when Gas1 is induced, Ret-mediated GDNF-dependent survival effects are compromised.