Citation
- Authors: Su, C. H., Wang, C. Y., Lan, K. H., Li, C. P., Chao, Y., Lin, H. C., Lee, S. D., Lee, W. P.
- Year: 2011
- Journal: Cell Signal 23 1824-30
- Applications: in vitro / siRNA / INTERFERin
- Cell type: HeLa
Description: Human cervix epitheloid carcinoma cells
Abstract
Phosphorylation at Thr308 and Ser473 is known to activate Akt, a major kinase in mammalian cells. Once activated to turn on downstream signaling pathways, Akt returns to an inactive pool via PP2A-mediated dephosphorylation. We show here that Thr308 and Ser473 phosphorylations prompt Akt to enter the CHIP-mediated ubiquitin-proteasome pathway. Mutation at either Thr308 or Ser473 dampened its ability to bind to the U-box E3 ligase CHIP (C-terminal Hsp70 -interacting protein), and the Akt mutants revealed decreased rate of ubiquitination by CHIP. Our study unveils that the well-known phosphorylations responsible for Akt activation turn out to transduce recognition signals for Akt-CHIP binding and ensuing degradation.