The Fbw7/human CDC4 tumor suppressor targets proproliferative factor KLF5 for ubiquitination and degradation through multiple phosphodegron motifs.
The proproliferative transcription factor KLF5 plays an important role in promoting cell proliferation and tumorigenesis. KLF5 is a short-lived protein that can be rapidly degraded through the ubiquitin-proteasome pathway in cancer cells. However, the mechanisms regulating protein stability remain poorly understood. In this study, the tumor suppressor Fbw7, a component of the SCF complex (SCF(Fbw7)) E3 ubiquitin ligase, specifically promoted the degradation and ubiquitination of KLF5 but had little effect on the stability of KLF4. Fbw7 interacted with KLF5 in a CDC4 phosphodegron (CPD)-dependent manner. Three CPDs were found in the KLF5 protein. Simultaneous mutation of these CPDs significantly abolished Fbw7-mediated ubiquitination and degradation. Furthermore, Fbw7 deficiency dramatically delayed KLF5 turnover and led to the accumulation of KLF5 protein in cancer cells. Glycogen synthase kinase-3beta could phosphorylate and promote Fbw7-mediated KLF5 degradation. More importantly, Fbw7 negatively regulated the biological activity of KLF5 in gene regulation and cell proliferation. Taken together, these data indicate that Fbw7 is a key negative regulator controlling KLF5-mediated cell proliferation and suggest an additional mechanism linking the loss of Fbw7 function to tumorigenesis.
Liu
Ning
N
Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China.
Li
Hui
H
Li
Shuangxi
S
Shen
Mingyue
M
Xiao
Ning
N
Chen
Yunfei
Y
Wang
Yan
Y
Wang
Weichao
W
Wang
Rui
R
Wang
Qian
Q
Sun
Jianhua
J
Wang
Ping
P
D020816:Amino Acid Motifs; D018797:Cell Cycle Proteins / Q000378:metabolism / Q000502:physiology*; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003593:Cytoplasm / Q000378:metabolism; D044783:F-Box Proteins / Q000378:metabolism / Q000502:physiology*; D000073979:F-Box-WD Repeat-Containing Protein 7; D005434:Flow Cytometry / Q000379:methods; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006367:HeLa Cells; D006801:Humans; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism / Q000502:physiology*; D009154:Mutation; D010766:Phosphorylation; D025801:Ubiquitin / Q000737:chemistry*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism / Q000502:physiology*
D018797:Cell Cycle Proteins; D044783:F-Box Proteins; D000073979:F-Box-WD Repeat-Containing Protein 7; C513273:FBXW7 protein, human; C000715467:KLF4 protein, human; C492214:KLF5 protein, human; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D025801:Ubiquitin; D044767:Ubiquitin-Protein Ligases; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3
J Biol Chem. 2005 Dec 16;280(50):41553-61
16223724
J Biol Chem. 2001 Sep 14;276(37):34355-8
11443140
Nat Med. 2008 Jun;14(6):656-66
18500350
Mol Cell Biol. 2009 Dec;29(23):6192-205
19797085
Int J Cancer. 2007 Jul 1;121(1):80-87
17330240
Clin Cancer Res. 2006 Apr 15;12(8):2442-8
16638850
Oncogene. 2009 Jun 25;28(25):2393-405
19421138
J Biol Chem. 2009 Apr 3;284(14):9549-57
19189969
Science. 2008 Sep 12;321(5895):1499-502
18787170
Curr Biol. 2004 Oct 26;14(20):1852-7
15498494
Histol Histopathol. 2009 Oct;24(10):1343-55
19688699
Mol Cancer Ther. 2009 Mar;8(3):563-70
19240162
Nat Cell Biol. 2008 Mar;10(3):353-60
18264089
Science. 2008 Nov 7;322(5903):923-9
18988848
J Biol Chem. 2008 Nov 14;283(46):31991-2002
18782761
Science. 2004 Feb 27;303(5662):1374-8
14739463
J Exp Med. 2007 Aug 6;204(8):1813-24
17646409
Genes Dev. 2008 Jan 15;22(2):252-64
18198341
Nucleic Acids Res. 2003 Apr 15;31(8):2196-208
12682370
Proc Natl Acad Sci U S A. 2004 Jun 15;101(24):9085-90
15150404
Cell Div. 2007 Feb 13;2:7
17298674
J Biol Chem. 2003 Feb 21;278(8):6363-70
12488444
Mol Cell Biol. 2001 Jan;21(2):562-74
11134343
Oncogene. 2007 Apr 5;26(16):2386-94
17016436
J Biol Chem. 2004 Mar 26;279(13):12093-101
14726538
Gastroenterology. 2008 Apr;134(4):1007-16
18395082
Trends Biochem Sci. 2010 Mar;35(3):161-8
19884009
Prostate. 2003 May 1;55(2):81-8
12661032
Cancer Cell. 2008 Jan;13(1):36-47
18167338
EMBO J. 2004 May 19;23(10):2116-25
15103331
J Cell Physiol. 2001 Aug;188(2):143-60
11424081
Cancer Res. 2005 Nov 15;65(22):10394-400
16288030
Bioessays. 2007 Jun;29(6):549-57
17508399
J Biol Chem. 2006 May 26;281(21):14711-8
16595680
J Biol Chem. 2007 May 25;282(21):15541-9
17430902
Nature. 2004 Mar 4;428(6978):77-81
14999283
Cancer Res. 2007 Oct 1;67(19):9006-12
17909001
Cell. 2003 Jan 24;112(2):243-56
12553912
Int J Cancer. 2009 Jun 15;124(12):2829-36
19267401
Nature. 2004 Dec 9;432(7018):775-9
15592418
Nat Rev Cancer. 2008 Feb;8(2):83-93
18094723
Oncogene. 2005 May 5;24(20):3319-27
15735697
Oncogene. 2009 Oct 22;28(42):3702-13
19668233
Cancer Res. 2009 May 15;69(10):4125-33
19435907
J Biol Chem. 2004 Mar 26;279(13):12300-11
14711826
Cell Mol Life Sci. 2009 Aug;66(16):2691-706
19448973
J Biol Chem. 2001 Mar 9;276(10):6897-900
11152667
Mol Cell. 2007 Apr 13;26(1):131-43
17434132
J Cell Biol. 2008 Jun 16;181(6):913-20
18559665
Science. 2001 Oct 5;294(5540):173-7
11533444
Int J Cancer. 2006 Mar 15;118(6):1346-55
16184550
Cell Cycle. 2004 Jun;3(6):693-4
15118416
Cell Metab. 2005 Jun;1(6):379-91
16054087