Glycogen synthase kinase-3 couples AKT-dependent signaling to the regulation of p21Cip1 degradation
- Signaling via the phosphoinositide 3-kinase (PI3K)/AKT pathway is crucial for the regulation of endothelial cell (EC) proliferation and survival, which involves the AKT-dependent phosphorylation of the DNA repair protein p21(Cip1) at Thr-145. Because p21(Cip1) is a short-lived protein with a high proteasomal degradation rate, we investigated the regulation of p21(Cip1) protein levels by PI3K/AKT-dependent signaling. The PI3K inhibitors Ly294002 and wortmannin reduced p21(Cip1) protein abundance in human umbilical vein EC. However, mutation of the AKT site Thr-145 into aspartate (T145D) did not increase its protein half-life. We therefore investigated whether a kinase downstream of AKT regulates p21(Cip1) protein levels. In various cell types, AKT phosphorylates and inhibits glycogen synthase kinase-3 (GSK-3). Upon serum stimulation of EC, GSK-3beta was phosphorylated at Ser-9. Site-directed mutagenesis revealed that GSK-3 in vitro phosphorylated p21(Cip1) specifically at Thr-57 within the Cdk binding domain. Overexpression of GSK-3beta decreased p21(Cip1) protein levels in EC, whereas the specific inhibition of GSK-3 with lithium chloride interfered with p21(Cip1) degradation and increased p21(Cip1) protein about 10-fold in EC and cardiac myocytes (30 mm, p < 0.001). These data indicate that GSK-3 triggers p21(Cip1) degradation. In contrast, stimulation of AKT increases p21(Cip1) via inhibitory phosphorylation of GSK-3.
Author: | Lothar RössigGND, Cornel BadorffGND, Yvonne HolzmannGND, Andreas M. ZeiherORCiDGND, Stefanie DimmelerORCiDGND |
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URN: | urn:nbn:de:hebis:30:3-760027 |
DOI: | https://doi.org/10.1074/jbc.M106157200 |
ISSN: | 0021-9258 |
Pubmed Id: | https://pubmed.ncbi.nlm.nih.gov/11779850 |
Parent Title (English): | Journal of biological chemistry |
Publisher: | American Society for Biochemistry and Molecular Biology Publications |
Place of publication: | Bethesda, Md |
Document Type: | Article |
Language: | English |
Date of Publication (online): | 2021/01/04 |
Year of first Publication: | 2002 |
Publishing Institution: | Universitätsbibliothek Johann Christian Senckenberg |
Release Date: | 2023/11/14 |
Volume: | 277 |
Issue: | 12 |
Page Number: | 6 |
First Page: | 9684 |
Last Page: | 9689 |
HeBIS-PPN: | 516505998 |
Institutes: | Medizin |
Dewey Decimal Classification: | 6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit |
Sammlungen: | Universitätspublikationen |
Licence (German): | Creative Commons - CC BY - Namensnennung 4.0 International |