| 1. |
- Hamidi, Anahita, et al.
(författare)
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Polyubiquitination of Transforming Growth Factor beta (TGF beta)-associated Kinase 1 Mediates Nuclear Factor-kappa B Activation in Response to Different Inflammatory Stimuli
- 2012
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Ingår i: Journal of Biological Chemistry. - Rockville Pike : The American Society for Biochemistry and Molecular Biology (. - 0021-9258 .- 1083-351X. ; 287:1, s. 123-133
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Tidskriftsartikel (refereegranskat)abstract
- The transcription factor nuclear factor kappa B (NF-kappa B) plays a central role in regulating inflammation in response to several external signals. The TGF beta-associated kinase 1 (TAK1) is an upstream regulator of NF-kappa B signaling. In TGF beta-stimulated cells, TAK1 undergoes Lys-63-linked polyubiquitination at Lys-34 by TNF receptor-associated factor 6 and is thereby activated. The aim of this study was to investigate whether TAK1 polyubiquitination at Lys-34 is also essential for NF-kappa B activation via TNF receptor, IL-1 receptor and toll-like receptor 4. We observed that TAK1 polyubiquitination occurred at Lys-34 and required the E3 ubiquitin ligase TNF receptor-associated factor 6 after stimulation of cells with IL-1 beta. Polyubiquitination of TAK1 also occurred at Lys-34 in cells stimulated by TNF-alpha and LPS, which activates TLR4, as well as in HepG2 and prostate cancer cells stimulated with TGF beta, which in all cases resulted in NF-kappa B activation. Expression of a K34R-mutant TAK1 led to a reduced NF-kappa B activation, IL-6 promoter activity, and proinflammatory cytokine secretion by TNF-alpha-stimulated PC-3U cells. Similar results were obtained in the mouse macrophage cell line RAW264.7 after LPS treatment. In conclusion, polyubiquitination of TAK1 is correlated with activation of TAK1 and is essential for activation of NF-kappa B signaling downstream of several receptors.
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| 2. |
- Hamidi, Anahita, et al.
(författare)
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Polyubiquitination of transforming growth factor β (TGFβ)-associated kinase 1 mediates nuclear factor-κB activation in response to different inflammatory stimuli
- 2012
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Ingår i: Journal of Biological Chemistry. - : The American Society for Biochemistry and Molecular Biology, Inc.. - 0021-9258 .- 1083-351X. ; 287:1, s. 123-133
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Tidskriftsartikel (refereegranskat)abstract
- The transcription factor nuclear factor κB (NF-κB) plays a central role in regulating inflammation in response to several external signals. The TGFβ-associated kinase 1 (TAK1) is an upstream regulator of NF-κB signaling. In TGFβ-stimulated cells, TAK1 undergoes Lys-63-linked polyubiquitination at Lys-34 by TNF receptor-associated factor 6 and is thereby activated. The aim of this study was to investigate whether TAK1 polyubiquitination at Lys-34 is also essential for NF-κB activation via TNF receptor, IL-1 receptor and toll-like receptor 4. We observed that TAK1 polyubiquitination occurred at Lys-34 and required the E3 ubiquitin ligase TNF receptor-associated factor 6 after stimulation of cells with IL-1β. Polyubiquitination of TAK1 also occurred at Lys-34 in cells stimulated by TNF-α and LPS, which activates TLR4, as well as in HepG2 and prostate cancer cells stimulated with TGFβ, which in all cases resulted in NF-κB activation. Expression of a K34R-mutant TAK1 led to a reduced NF-κB activation, IL-6 promoter activity, and proinflammatory cytokine secretion by TNF-α-stimulated PC-3U cells. Similar results were obtained in the mouse macrophage cell line RAW264.7 after LPS treatment. In conclusion, polyubiquitination of TAK1 is correlated with activation of TAK1 and is essential for activation of NF-κB signaling downstream of several receptors.
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| 3. |
- Cedervall, Jessica, et al.
(författare)
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Platelets, NETs and cancer
- 2018
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Ingår i: Thrombosis Research. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0049-3848 .- 1879-2472. ; 164, s. S148-S152
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Tidskriftsartikel (refereegranskat)abstract
- In addition to the central role of platelets in hemostasis, they contribute to pathological conditions such as inflammation and tumor progression. Aberrant expression and/or exposure of pro-coagulant factors in the tumor microenvironment induce platelet activation and subsequent release of growth factors from platelet granules. Cancer patients are commonly affected by thrombotic events, as a result of tumor-induced platelet activation. A novel player potentially contributing to cancer-associated thrombosis is the formation of neutrophil extracellular traps (NETs). NETs are composed of externalized DNA of nuclear or mitochondrial origin, bound to histones and granular proteases such as neutrophil elastase (NE) and myeloperoxidase (MPO). These extracellular traps help neutrophils to catch and kill pathogens such as bacteria, virus and fungi. It is now clear that NETs form also under conditions of sterile inflammation such as cancer and autoimmunity and can promote thrombosis. Recent data show that platelets play a key role in determining when and where NETs should form. This review will highlight our current insight in the role of platelets as regulators of NET formation, both during infection and sterile inflammation.
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| 4. |
- Hamidi, Anahita
(författare)
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Molecular mechanisms for activation of non-canonical TGFβ pathways and their importance during prostate cancer progression
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Prostate cancer is the most common invasive cancer diagnosed in men and a major and growing health problem in Western countries. Deregulation of different pathways has been implicated in progression of prostate cancer, namely nuclear factor kappa enhancer binding protein (NF-κB), transforming growth factor β (TGFβ), phosphoinositide 3ʹ-kinase/AKT (PI3K/AKT) and Src kinase pathways. However, the detailed mechanisms by which TGFβ activates these pathways to contribute in tumorigenesis and invasive behavior of prostate cancer cells have not been elucidated.We have demonstrated (paper I) that the E3 ligase activity of TRAF6 is crucial for recruitment of the regulatory subunit of PI3K, p85α, to TβRI and for TGFβ-induced Lys63-linked polyubiquitination of p85α. TRAF6 is required for the TGFβ-induced recruitment of AKT to the complex of PI3K and TβRI, where the polyubiquitination and activation of AKT occurs. When activated, AKT promotes TGFβ-induced cell migration which is dependent on p85 and PI3K activity, as well as on TRAF6, but not on TβRI kinase activity. Thus, TGFβ-induced activation of PI3K/AKT induces cell motility contributing to the progression of cancer.We have demonstrated (paper II) a pivotal role of TAK1 polyubiquitination in three different pathways, including TNFR, IL-1R, and TLR4 signaling. Lys63-linked polyubiquitination of TAK1 at Lys34 is essential for downstream signaling to NF-κB-mediated target gene expression in both cancer and immune cells. These findings are of importance for the understanding of the mechanism of activation of NF-κB in inflammation and may aid in the development of new therapeutic strategies to treat chronic inflammation and cancer.We have also shown (paper III) that TGFβ activates the tyrosine kinase Src via formation of a complex between TβRI and Src. The E3 ligase TRAF6 promotes the formation of the complex in a manner not dependent on its ubiquitin ligase activity, suggesting that TRAF6 acts as an adaptor. Moreover, the activation of Src is not dependent on the kinase activity of TβRI. On a functional level, Src activity was found to be necessary for TGFβ-induced chemotaxis.In conclusion, we have elucidated molecular mechanisms whereby TGFβ activates non-Smad pathways, i.e. PI3K and Src. Our findings shed light on the pro-tumorigenesis mechanisms of TGFβ. In addition, we have demonstrated how the activation of TAK1, an important component of the TGFβ non-Smad pathway, by TGFβ and other stimuli leads to the activation of NF-κB and thereby induction of inflammation which likely contributes to prostate cancer progression.
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| 5. |
- Hamidi, Anahita, et al.
(författare)
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TGF-β promotes PI3K-AKT signaling and prostate cancer cell migration through the TRAF6-mediated ubiquitylation of p85α
- 2017
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Ingår i: Science Signaling. - : American Association for the Advancement of Science. - 1945-0877 .- 1937-9145. ; 10:486
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- TGF-β signaling stimulates various intracellular pathways that can promote migration in tumor cells. These pathways are generally thought to be either dependent or independent of transcription factors called SMADs. One of the SMAD-independent pathways (PI3K-AKT) is mediated by a direct interaction between PI3K and the TGF-β type I receptor. However, Hamidi et al. found that the TGF-β–induced activation of PI3K depends on another ubiquitin ligase–mediated mechanism and a SMAD protein but is independent of the kinase function of TβRI. The binding of TGF-β to its receptor triggered the recruitment of PI3K and the ubiquitin ligase TRAF6, which polyubiquitylated the regulatory PI3K subunit p85α, thus enabling phosphorylation of the catalytic PI3K subunit p110, but only in the presence of SMAD7. The abundance of ubiquitylated p85α correlated with migration in cultured cells and prostate tumor grade in patient samples. TRAF6 mediates activation of the other “SMAD-independent” (JNK) pathway. These data suggest that, although distinct, the TGF-β signaling pathways are not as insulated from each other as was once thought.
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| 6. |
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| 7. |
- Thakur, Noopur, et al.
(författare)
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Smad7 Enhances TGF-β-Induced Transcription of c-Jun and HDAC6 Promoting Invasion of Prostate Cancer Cells
- 2020
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Ingår i: iScience. - : Cell Press. - 2589-0042. ; 23:9
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor β (TGF-β) enhances migration and invasion of cancer cells, causing life-threatening metastasis. Smad7 expression is induced by TGF-β to control TGF-β signaling in a negative feedback manner. Here we report an additional function of Smad7, i.e., to enhance TGF-β induction of c-Jun and HDAC6 via binding to their regulatory regions, promoting migration and invasion of prostate cancer cells. Lysine 102 in Smad7 is crucial for binding to specific consensus sites in c-Jun and HDAC6, even when endogenous Smad2, 3, and 4 were silenced by siRNA. A correlation between the mRNA expression of Smad7 and HDAC6, Smad7 and c-Jun, and c-Jun and HDAC6 was found in public databases from analyses of prostate cancer tissues. High expression of Smad7, HDAC6, and c-Jun correlated with poor prognosis for patients with prostate cancer. The knowledge that Smad7 can activate transcription of proinvasive genes leading to prostate cancer progression provides clinically relevant information.
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| 8. |
- Wang, Kehuan, 1992-, et al.
(författare)
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SUMOylation of PDGF receptor α affects signaling via PLCγ and STAT3, and cell proliferation
- 2023
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Ingår i: BMC Molecular and Cell Biology. - : BioMed Central (BMC). - 2661-8850. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe platelet-derived growth factor (PDGF) family of ligands exerts their cellular effects by binding to α- and β-tyrosine kinase receptors (PDGFRα and PDGFRβ, respectively). SUMOylation is an important posttranslational modification (PTM) which regulates protein stability, localization, activation and protein interactions. A mass spectrometry screen has demonstrated SUMOylation of PDGFRα. However, the functional role of SUMOylation of PDGFRα has remained unknown.ResultsIn the present study, we validated that PDGFRα is SUMOylated on lysine residue 917 as was previously reported using a mass spectrometry approach. Mutation of lysine residue 917 to arginine (K917R) in PDGFRα substantially decreased SUMOylation, indicating that this amino acid residue is a major SUMOylation site. Whereas no difference in the stability of wild-type and mutant receptor was observed, the K917R mutant PDGFRα was less ubiquitinated than wild-type PDGFRα. The internalization and trafficking of the receptor to early and late endosomes were not affected by the mutation, neither was the localization of the PDGFRα to Golgi. However, the K917R mutant PDGFRα showed delayed activation of PLC-γ and enhanced activation of STAT3. Functional assays showed that the mutation of K917 of PDGFRα decreased cell proliferation in response to PDGF-BB stimulation.ConclusionsSUMOylation of PDGFRα decreases ubiquitination of the receptor and affects ligand-induced signaling and cell proliferation.
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| 9. |
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| 10. |
- Yakymovych, Ihor, et al.
(författare)
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The type II TGF-β receptor phosphorylates Tyr 182 in the type I receptor to activate downstream Src signaling
- 2022
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Ingår i: Science Signaling. - : American Association for the Advancement of Science (AAAS). - 1945-0877 .- 1937-9145. ; 15:760
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor–β (TGF-β) signaling has important roles during embryonic development and in tissue homeostasis. TGF-β ligands exert cellular effects by binding to type I (TβRI) and type II (TβRII) receptors and induce both SMAD-dependent as well as SMAD-independent intracellular signaling pathways. Activation of the tyrosine kinase Src is one such SMAD-independent consequence of TGF-β signaling. We investigated the mechanism by which TGF-β stimulation activates Src in human and mouse cells. Before TGF-β stimulation, inactive Src was present in a complex with TβRII. Upon TGF-β1 stimulation, which induces the formation of a complex of TβRI and TβRII, TβRII phosphorylated TβRI on serine and threonine residues, which promotes TβRI kinase activity, and on Tyr182. The SH2 domain of Src bound to phosphporylated Tyr182, leading to activation of Src kinase activity. Interaction of the Src SH3 domain with a proline-rich region in TβRI also contributed to binding. TGF-β1–induced Src activation depended on the kinase activity of TβRII but not on that of TβRI, indicating that binding to TβRI activated Src through a non-enzymatic mechanism. Activated Src then phosphorylated TβRI on several tyrosine residues, which may stabilize Src binding to the receptor. In functional assays, Src activation was required for the TGF-β–induced production of fibronectin and for migration in human breast carcinoma cells and for the induction of α-smooth muscle actin (α-SMA) and actin reorganization in mouse fibroblasts. Thus, TGF-β induces Src activation by stimulating a direct interaction with TβRI that depends on tyrosine phosphorylation of TβRI by TβRII.
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