[HTML][HTML] Phosphorylation and functional inactivation of TSC2 by Erk: implications for tuberous sclerosisand cancer pathogenesis

L Ma, Z Chen, H Erdjument-Bromage, P Tempst… - Cell, 2005 - cell.com
Cell, 2005cell.com
Tuberous sclerosis (TSC) is a tumor syndrome caused by mutation in TSC1 or TSC2 genes.
TSC tumorigenesis is not always accompanied by loss of heterozygosity (LOH). Recently,
extracellular signal-regulated kinase (Erk) has been found activated in TSC lesions lacking
TSC1 or TSC2 LOH. Here, we show that Erk may play a critical role in TSC progression
through posttranslational inactivation of TSC2. Erk-dependent phosphorylation leads to
TSC1-TSC2 dissociation and markedly impairs TSC2 ability to inhibit mTOR signaling, cell …
Summary
Tuberous sclerosis (TSC) is a tumor syndrome caused by mutation in TSC1 or TSC2 genes. TSC tumorigenesis is not always accompanied by loss of heterozygosity (LOH). Recently, extracellular signal-regulated kinase (Erk) has been found activated in TSC lesions lacking TSC1 or TSC2 LOH. Here, we show that Erk may play a critical role in TSC progression through posttranslational inactivation of TSC2. Erk-dependent phosphorylation leads to TSC1-TSC2 dissociation and markedly impairs TSC2 ability to inhibit mTOR signaling, cell proliferation, and oncogenic transformation. Importantly, expression of an Erk nonphosphorylatable TSC2 mutant in TSC2+/− tumor cells where Erk is constitutively activated blocks tumorigenecity in vivo, while wild-type TSC2 is ineffective. Our findings position the Ras/MAPK pathway upstream of the TSC complex and suggest that Erk may modulate mTOR signaling and contribute to disease progression through phosphorylation and inactivation of TSC2.
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