Huntington's disease (HD) is characterized by progressive neurodegeneration of striatal neurons in the brain, often leading to dementia. A mutation in the gene encoding huntingtin and nuclear accumulation of the mutant protein are associated with the pathology of HD, but it is not yet clear why these neurons die. Growth factors that promote cell survival are attractive therapeutic agents for neurodegenerative diseases, and Humbert et al. report that insulinlike growth factor 1 (IGF-1), which activates the protein kinase Akt, shows neuroprotective potential. The IGF-1-induced phosphorylation of huntingtin in vitro and in cultured neurons blocked the formation of nuclear inclusions and cell death (apoptosis). Furthermore, postmortem brain samples from HD patients showed decreased amounts of Akt, consistent with the proposal that the phosphorylation status of huntingtin may alter its interactions with apoptotic effectors. — LDC
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