RGD Reference Report - X-linked inhibitor of apoptosis (XIAP) inhibits c-Jun N-terminal kinase 1 (JNK1) activation by transforming growth factor beta1 (TGF-beta1) through ubiquitin-mediated proteosomal degradation of the TGF-beta1-activated kinase 1 (TAK1). - Rat Genome Database

Send us a Message



Submit Data |  Help |  Video Tutorials |  News |  Publications |  Download |  REST API |  Citing RGD |  Contact   

X-linked inhibitor of apoptosis (XIAP) inhibits c-Jun N-terminal kinase 1 (JNK1) activation by transforming growth factor beta1 (TGF-beta1) through ubiquitin-mediated proteosomal degradation of the TGF-beta1-activated kinase 1 (TAK1).

Authors: Kaur, S  Wang, F  Venkatraman, M  Arsura, M 
Citation: Kaur S, etal., J Biol Chem. 2005 Nov 18;280(46):38599-608. Epub 2005 Sep 12.
RGD ID: 1579748
Pubmed: PMID:16157589   (View Abstract at PubMed)
DOI: DOI:10.1074/jbc.M505671200   (Journal Full-text)

Active NF-kappaB renders malignant hepatocytes refractory to the growth inhibitory and pro-apoptotic properties of transforming growth factorbeta1 (TGF-beta1). NF-kappaB counteracts TGF-beta1-induced apoptosis through up-regulation of downstream target genes, such as XIAP and Bcl-X(L), which in turn inhibit the intrinsic pathway of apoptosis. In addition, induction of NF-kappaB by TGF-beta1 inhibits JNK signaling, thereby attenuating TGF-beta1-induced cell death of normal hepatocytes. However, the mechanism involved in the negative cross-talk between the NF-kappaB and JNK pathways during TGF-beta1 signaling has not been determined. In this study, we have identified the XIAP gene as one of the critical mediators of NF-kappaB-mediated suppression of JNK signaling. We show that NF-kappaB plays a role in the up-regulation of XIAP gene expression in response to TGF-beta1 treatment and forms a TGF-beta1-inducible complex with TAK1. Furthermore, we show that the RING domain of XIAP mediates TAK1 polyubiquitination, which then targets this molecule for proteosomal degradation. Down-regulation of TAK1 protein expression inhibits TGF-beta1-mediated activation of JNK and apoptosis. Conversely, silencing of XIAP promotes persistent JNK activation and potentiates TGF-beta1-induced apoptosis. Collectively, our findings identify a novel mechanism for the regulation of JNK activity by NF-kappaB during TGF-beta1 signaling and raise the possibility that pharmacologic inhibition of the NF-kappaB/XIAP signaling pathway might selectively abolish the pro-oncogenic activity of TGF-beta1 in advanced hepatocellular carcinomas (HCCs) without affecting the pro-apoptotic effects of TGF-beta1 involved in normal liver homeostasis.

Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
positive regulation of apoptotic process  IDA 1579748 RGD 

Objects Annotated

Genes (Rattus norvegicus)
Tgfb1  (transforming growth factor, beta 1)


Additional Information