WIP1 phosphatase is a negative regulator of NF-kappaB signalling.
Post-translational modifications of NF-kappaB through phosphorylations enhance its transactivation potential. Much is known about the kinases that phosphorylate NF-kappaB, but little is known about the phosphatases that dephosphorylate it. By using a genome-scale siRNA screen, we identified the WIP1 phosphatase as a negative regulator of NF-kappaB signalling. WIP1-mediated regulation of NF-kappaB occurs in both a p38-dependent and independent manner. Overexpression of WIP1 resulted in decreased NF-kappaB activation in a dose-dependent manner, whereas WIP1 knockdown resulted in increased NF-kappaB function. We show that WIP1 is a direct phosphatase of Ser 536 of the p65 subunit of NF-kappaB. Phosphorylation of Ser 536 is known to be essential for the transactivation function of p65, as it is required for recruitment of the transcriptional co-activator p300. WIP1-mediated regulation of p65 regulated binding of NF-kappaB to p300 and hence chromatin remodelling. Consistent with our results, mice lacking WIP1 showed enhanced inflammation. These results provide the first genetic proof that a phosphatase directly regulates NF-kappaB signalling in vivo.
Laboratory of NF- kappaB signalling, Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673.
Joanne
J
Chew
Subhra
S
Biswas
Sathyavageeswaran
S
Shreeram
Mahathir
M
Humaidi
Ee Tsin
ET
Wong
Manprit Kaur
MK
Dhillion
Hsiangling
H
Teo
Amit
A
Hazra
Cheok Chit
CC
Fang
Eduardo
E
López-Collazo
Dmitry V
DV
Bulavin
Vinay
V
Tergaonkar
D000825:Animal Structures / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D045744:Cell Line, Tumor; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D008817:Mice, Mutant Strains; D008954:Models, Biological; D016328:NF-kappa B / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000502:physiology*; D010766:Phosphorylation / Q000187:drug effects; D000071636:Protein Phosphatase 2C; D034741:RNA, Small Interfering / Q000235:genetics; D018805:Sepsis / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000494:pharmacology; D050880:p300-CBP Transcription Factors / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
D007375:Interleukin-1; D008070:Lipopolysaccharides; D016328:NF-kappa B; D034741:RNA, Small Interfering; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D050880:p300-CBP Transcription Factors; D048051:p38 Mitogen-Activated Protein Kinases; C000607458:PPM1D protein, human; D010749:Phosphoprotein Phosphatases; C000607468:Ppm1d protein, mouse; D000071636:Protein Phosphatase 2C