Abstract
The transcription factor NF-kappaB is activated by the degradation of its inhibitor IkappaBalpha, resulting in its nuclear translocation. However, the mechanism by which nuclear NF-kappaB is subsequently regulated is not clear. Here we demonstrate that NF-kappaB function is regulated by Pin1-mediated prolyl isomerization and ubiquitin-mediated proteolysis of its p65/RelA subunit. Upon cytokine treatment, Pin1 binds to the pThr254-Pro motif in p65 and inhibits p65 binding to IkappaBalpha, resulting in increased nuclear accumulation and protein stability of p65 and enhanced NF-kappaB activity. Significantly, Pin1-deficient mice and cells are refractory to NF-kappaB activation by cytokine signals. Moreover, the stability of p65 is controlled by ubiquitin-mediated proteolysis, facilitated by a cytokine signal inhibitor, SOCS-1, acting as a ubiquitin ligase. These findings uncover two important mechanisms of regulating NF-kappaB signaling and offer new insight into the pathogenesis and treatment of some human diseases such as cancers.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Motifs
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Animals
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Binding Sites
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Breast Neoplasms / metabolism
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Breast Neoplasms / pathology
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Carrier Proteins / metabolism
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Cells, Cultured
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Cytokines / metabolism
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DNA-Binding Proteins / metabolism*
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Female
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Fibroblasts / cytology
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Fibroblasts / physiology
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Humans
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I-kappa B Kinase
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I-kappa B Proteins / metabolism
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Intracellular Signaling Peptides and Proteins*
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Mice
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Mice, Knockout
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NF-KappaB Inhibitor alpha
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NF-kappa B / antagonists & inhibitors
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NF-kappa B / metabolism*
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NIMA-Interacting Peptidylprolyl Isomerase
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Peptidylprolyl Isomerase / genetics
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Peptidylprolyl Isomerase / metabolism*
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Phosphorylation
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Protein Binding
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Protein Serine-Threonine Kinases / metabolism
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Protein Subunits / metabolism
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Repressor Proteins / metabolism
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Signal Transduction / physiology*
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Suppressor of Cytokine Signaling 1 Protein
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Suppressor of Cytokine Signaling Proteins
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Transcription Factor RelA
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Transcriptional Activation
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Ubiquitin / metabolism*
Substances
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Carrier Proteins
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Cytokines
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DNA-Binding Proteins
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I-kappa B Proteins
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Intracellular Signaling Peptides and Proteins
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NF-kappa B
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NFKBIA protein, human
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NIMA-Interacting Peptidylprolyl Isomerase
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Nfkbia protein, mouse
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Protein Subunits
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Repressor Proteins
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SOCS1 protein, human
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Socs1 protein, mouse
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Suppressor of Cytokine Signaling 1 Protein
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Suppressor of Cytokine Signaling Proteins
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Transcription Factor RelA
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Ubiquitin
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NF-KappaB Inhibitor alpha
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Protein Serine-Threonine Kinases
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CHUK protein, human
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Chuk protein, mouse
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I-kappa B Kinase
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IKBKB protein, human
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IKBKE protein, human
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Ikbkb protein, mouse
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Ikbke protein, mouse
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PIN1 protein, human
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Peptidylprolyl Isomerase
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Pin1 protein, mouse