» Articles » PMID: 19797085

Beta-TrCP-mediated Ubiquitination and Degradation of PHLPP1 Are Negatively Regulated by Akt

Overview
Journal Mol Cell Biol
Specialty Cell Biology
Date 2009 Oct 3
PMID 19797085
Citations 68
Authors
Affiliations
Soon will be listed here.
Abstract

PHLPP1 belongs to a novel family of Ser/Thr protein phosphatases that serve as tumor suppressors by negatively regulating Akt signaling. Our recent studies have demonstrated that loss of PHLPP expression occurs at high frequency in colorectal cancer. In this study, we identified PHLPP1 as a proteolytic target of a beta-TrCP-containing Skp-Cullin 1-F-box protein (SCF) complex (SCF(beta-TrCP)) E3 ubiquitin ligase in a phosphorylation-dependent manner. Overexpression of wild-type but not DeltaF-box mutant beta-TrCP leads to decreased expression and increased ubiquitination of PHLPP1, whereas knockdown of endogenous beta-TrCP has the opposite effect. In addition, we show that the beta-TrCP-mediated degradation requires phosphorylation of PHLPP1 by casein kinase I and glycogen synthase kinase 3beta (GSK-3beta), and activation of the phosphatidylinositol 3-kinase/Akt pathway suppresses the degradation of PHLPP1 by inhibiting the GSK-3beta activity. Furthermore, expression of a degradation-deficient PHLPP1 mutant in colon cancer cells results in a more effective dephosphorylation of Akt and inhibition of cell growth. Taken together, our findings demonstrate a key role for beta-TrCP in controlling the level of PHLPP1, and activation of Akt negatively regulates this degradation process.

Citing Articles

Modeling unveils sex differences of signaling networks in mouse embryonic stem cells.

Sultana Z, Dorel M, Klinger B, Sieber A, Dunkel I, Bluthgen N Mol Syst Biol. 2023; 19(11):e11510.

PMID: 37735975 PMC: 10632733. DOI: 10.15252/msb.202211510.


SKP2 Contributes to AKT Activation by Ubiquitination Degradation of PHLPP1, Impedes Autophagy, and Facilitates the Survival of Thyroid Carcinoma.

Shao Y, Ren W, Dai H, Yang F, Li X, Zhang S Mol Cells. 2023; 46(6):360-373.

PMID: 36694914 PMC: 10258456. DOI: 10.14348/molcells.2022.2242.


Chondrocytic and pharmacokinetic properties of Phlpp inhibitors.

Taylor E, Weaver S, Zars E, Turner C, Buhrow S, Reid J Osteoarthr Cartil Open. 2022; 3(3):100190.

PMID: 36474816 PMC: 9718091. DOI: 10.1016/j.ocarto.2021.100190.


Comprehensive Characterization of a Novel E3-Related Gene Signature With Implications in Prognosis and Immunotherapy of Low-Grade Gliomas.

Tan S, Spear R, Zhao J, Sun X, Wang P Front Genet. 2022; 13:905047.

PMID: 35832194 PMC: 9271851. DOI: 10.3389/fgene.2022.905047.


Potassium Effects on NCC Are Attenuated during Inhibition of Cullin E3-Ubiquitin Ligases.

Murali S, Little R, Poulsen S, Ferdaus M, Ellison D, McCormick J Cells. 2022; 11(1).

PMID: 35011657 PMC: 8750104. DOI: 10.3390/cells11010095.


References
1.
Qiao M, Iglehart J, Pardee A . Metastatic potential of 21T human breast cancer cells depends on Akt/protein kinase B activation. Cancer Res. 2007; 67(11):5293-9. DOI: 10.1158/0008-5472.CAN-07-0877. View

2.
Manning B . Balancing Akt with S6K: implications for both metabolic diseases and tumorigenesis. J Cell Biol. 2004; 167(3):399-403. PMC: 2172491. DOI: 10.1083/jcb.200408161. View

3.
Shaw R, Cantley L . Ras, PI(3)K and mTOR signalling controls tumour cell growth. Nature. 2006; 441(7092):424-30. DOI: 10.1038/nature04869. View

4.
Jia J, Zhang L, Zhang Q, Tong C, Wang B, Hou F . Phosphorylation by double-time/CKIepsilon and CKIalpha targets cubitus interruptus for Slimb/beta-TRCP-mediated proteolytic processing. Dev Cell. 2005; 9(6):819-30. DOI: 10.1016/j.devcel.2005.10.006. View

5.
Brognard J, Sierecki E, Gao T, Newton A . PHLPP and a second isoform, PHLPP2, differentially attenuate the amplitude of Akt signaling by regulating distinct Akt isoforms. Mol Cell. 2007; 25(6):917-31. DOI: 10.1016/j.molcel.2007.02.017. View