scholarly journals The PAAD/PYRIN-Family Protein ASC Is a Dual Regulator of a Conserved Step in Nuclear Factor κB Activation Pathways

2002 ◽  
Vol 196 (12) ◽  
pp. 1605-1615 ◽  
Author(s):  
Christian Stehlik ◽  
Loredana Fiorentino ◽  
Andrea Dorfleutner ◽  
Jean-Marie Bruey ◽  
Eugenia M. Ariza ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Adaptor Protein ◽  
Large Family ◽  
Nuclear Factor Κb ◽  
Inhibitory Influence ◽  
Nuclear Factor ◽  
Death Domain ◽  
Protein Levels ◽  
Inflammatory Stimuli ◽  
Activation Pathways

Apoptosis-associated speck-like protein containing a Caspase recruitment domain (ASC) belongs to a large family of proteins that contain a Pyrin, AIM, ASC, and death domain-like (PAAD) domain (also known as PYRIN, DAPIN, Pyk). Recent data have suggested that ASC functions as an adaptor protein linking various PAAD-family proteins to pathways involved in nuclear factor (NF)-κB and pro-Caspase-1 activation. We present evidence here that the role of ASC in modulating NF-κB activation pathways is much broader than previously suspected, as it can either inhibit or activate NF-κB, depending on cellular context. While coexpression of ASC with certain PAAD-family proteins such as Pyrin and Cryopyrin increases NF-κB activity, ASC has an inhibitory influence on NF-κB activation by various proinflammatory stimuli, including tumor necrosis factor (TNF)α, interleukin 1β, and lipopolysaccharide (LPS). Elevations in ASC protein levels or of the PAAD domain of ASC suppressed activation of IκB kinases in cells exposed to pro-inflammatory stimuli. Conversely, reducing endogenous levels of ASC using siRNA enhanced TNF- and LPS-induced degradation of the IKK substrate, IκBα. Our findings suggest that ASC modulates diverse NF-κB induction pathways by acting upon the IKK complex, implying a broad role for this and similar proteins containing PAAD domains in regulation of inflammatory responses.

scholarly journals Canonical, Non-Canonical and Atypical Pathways of Nuclear Factor кb Activation in Preeclampsia

2020 ◽  
Vol 21 (15) ◽  
pp. 5574
Author(s):  
Agata Sakowicz ◽  
Michalina Bralewska ◽  
Tadeusz Pietrucha ◽  
Dominika E Habrowska-Górczyńska ◽  
Agnieszka W Piastowska-Ciesielska ◽  
...  
Keyword(s):  
Western Blot ◽  
Real Time ◽  
Protein Level ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Rt Pcr ◽  
Protein Levels ◽  
Activation Pathways ◽  
Expression And Activity

Although higher nuclear factor κB (NFκB) expression and activity is observed in preeclamptic placentas, its mechanism of activation is unknown. This is the first study to investigate whether the canonical, non-canonical, or atypical NFκB activation pathways may be responsible for the higher activation of NFκB observed in preeclamptic placentas. The study included 268 cases (130 preeclamptic women and 138 controls). We studied the expression of the genes coding for NFκB activators (NIK, IKKα, IKKβ, and CK2α) and inhibitors (IκBα and IκBβ) using RT-PCR in real time. The RT-PCR results were verified on the protein level using ELISA and Western blot. To determine the efficiency of the pathways, the ratios of activator(s) to one of the inhibitors (IκBα or IκBβ) were calculated for each studied pathway. The preeclamptic placentas demonstrated significantly lower IKKα and CK2α but higher IκBα and IκBβ protein levels. In addition, the calculated activator(s) to inhibitor (IκBα or IκBβ) ratios suggested that all studied pathways might be downregulated in preeclamptic placentas. Our results indicate that preeclamptic placentas may demonstrate mechanisms of NFκB activation other than the canonical, non-canonical, and atypical forms. In these mechanisms, inhibitors of NFκB may play a key role. These observations broaden the existing knowledge regarding the molecular background of preeclampsia development.

scholarly journals A novel splice variant of mouse interleukin-1-receptor-associated kinase-1 (IRAK-1) activates nuclear factor-kappaB (NF-kappaB) and c-Jun N-terminal kinase (JNK)

2003 ◽  
Vol 370 (1) ◽  
pp. 159-166 ◽  
Author(s):  
Ken YANAGISAWA ◽  
Kenji TAGO ◽  
Morisada HAYAKAWA ◽  
Motomichi OHKI ◽  
Hiroyuki IWAHANA ◽  
...  
Keyword(s):  
Splice Variant ◽  
Interleukin 1 ◽  
Nuclear Factor Κb ◽  
Tumour Necrosis Factor Receptor ◽  
Acceptor Site ◽  
Nuclear Factor ◽  
Death Domain ◽  
Signalling Molecule ◽  
Novel Variant ◽  
Nf Kappab

Interleukin-1 (IL-1)-receptor-associated kinase (IRAK) is an indispensable signalling molecule for host-defence responses initiated by a variety of ligands that bind to members of the Toll/IL-1 receptor family. Here we report a novel splice variant of mouse IRAK-1, IRAK-1-S, which is generated by utilizing a new splicing acceptor site within exon 12. IRAK-1-S cDNA is shorter than the originally reported IRAK-1 (IRAK-1-W) cDNA by 271 nucleotides, and the subsequent frameshift causes a premature termination of translation after 23 amino acids, which are unique to the IRAK-1-S protein. To elucidate the physiological function of IRAK-1-S, we overexpressed it in 293T cells and studied the effects on the IL-1 signalling cascade. As it lacks the C-terminal region of IRAK-1-W that has been reported to contain the TRAF6 (tumour necrosis factor receptor-associated factor 6) binding domain, IRAK-1-S was unable to bind TRAF6 protein, which is a proposed downstream signalling molecule. However, IRAK-1-S overexpressed in 293T cells induced constitutive activation of nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK) independent of stimulation by IL-1, as did IRAK-1-W. To clarify the mechanism of NF-κB activation by IRAK-1-S in the absence of binding to TRAF6, we demonstrated that IRAK-1-S binds to IRAK-1-W through its death domain; the findings suggested that overexpressed IRAK-1-S may bind endogenous IRAK-1-W and activate TRAF6 through IRAK-1-W. These results also indicate that this novel variant may play roles in the activation of NF-κB and JNK by IL-1 and other ligands whose signal transduction is dependent on IRAK-1 under physiological conditions.

scholarly journals p62 acts as an oncogene and is targeted by miR-124-3p in glioma

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Danni Deng ◽  
Kaiming Luo ◽  
Hongmei Liu ◽  
Xichen Nie ◽  
Lian Xue ◽  
...  
Keyword(s):  
Glioma Cells ◽  
Nuclear Factor Κb ◽  
Autophagic Flux ◽  
Nuclear Factor ◽  
Oxygen Species ◽  
Human Glioma ◽  
Protein Levels ◽  
Novel Therapeutic

Abstract Background Glioma is the most common central nervous system (CNS) tumour. p62, an important autophagy adaptor, plays a crucial role in cancer. However, the role of p62 in the progression of glioma is poorly characterized. Methods We examined the expression of p62 in glioma tissues and cell lines. Then we investigated the function of p62 in vitro, and clarified the mechanism underlying the regulation of p62 expression. Results We revealed that p62 was upregulated at both the mRNA and protein levels in human glioma tissues irrelevant to isocitrate dehydrogenase (IDH) status. Then, we found that overexpression of p62 promoted glioma progression by promoting proliferation, migration, glycolysis, temozolomide (TMZ) resistance and nuclear factor κB (NF-κB) signalling pathway, and repressing autophagic flux and reactive oxygen species (ROS) in vitro. In accordance with p62 overexpression, knockdown of p62 exerted anti-tumour effects in glioma cells. Subsequently, we demonstrated that miR-124-3p directly targeted the 3′-UTR of p62 mRNA, leading to the downregulation of p62. Finally, we found that p62 function could be partially reversed by miR-124-3p overexpression. Conclusions Our results demonstrate that p62 can be targeted by miR-124-3p and acts as an oncogene in glioma, suggesting the potential value of p62 as a novel therapeutic target for glioma.

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