In cancer, activation of X-box binding protein (XBP1) has a critical role in tumorigenesis and cancer progression. Transcriptional regulatory mechanism of XBP1 in cancer development has been well known, however, regulation of ubiquitination and degradation of XBP1 has not been elucidated yet. Here we show that Fbw7, a substrate recognition component of the SKP1-Cullin-F-box-type E3 ligase, interacts with XBP1 in a phosphorylation-dependent manner, and facilitates XBP1 ubiquitination and protein degradation. Moreover, Fbw7 inhibits oncogenic pathways including NF-κB, AP1, and Myc induced by XBP1. Interestingly, XBP1 negatively regulates transcription of Fbw7 via a feedback mechanism through NF-κB/E2F-1 axis signaling pathway, suggesting that overexpression of XBP1s may contribute to low level of Fbw7 expression in human cancers. Therefore, a negative feedback loop between Fbw7 and XBP1 contributes to the regulation of tumor development and can be an attractive target for novel therapy in cancers.
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http://dx.doi.org/10.1038/s41389-019-0124-4 | DOI Listing |
Am J Respir Cell Mol Biol
January 2025
Wayne State University, Division of Pulmonary, Critical Care and Sleep Medicine, Detroit, Michigan, United States;
Numerous chronic human disorders are associated with immune activation by obscure antigen(s). We identified a novel sarcoidosis-epitope (ChainA) by immunoscreening of a novel T7 phage library and confirmed an abundance of ChainA IgG-antibody in sarcoidosis. We tested whether ChainA epitope elicits immune responses through B-cell activation, plasma cell differentiation and antibody production.
View Article and Find Full Text PDFCommun Biol
January 2025
Stem Cell Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan.
RNA helicase DEAD-box helicase 1 (DDX1) forms a complex with the RNA ligase 2´,3´-cyclic phosphate and 5´-OH ligase (RTCB), which plays a vital role in non-spliceosomal splicing of tRNA and X-box binding protein 1 (XBP1) mRNA. However, the importance of DDX1 in non-spliceosomal splicing has not been clarified. To analyze the functions of DDX1 in mammalian cells, we generated DDX1 cKO cells from the polyploid human U2OS cell line and found that splicing of intron-containing tRNAs was significantly disturbed in DDX1-deficient cells, whereas endoplasmic reticulum (ER) stress-induced splicing of XBP1 mRNA was unaffected.
View Article and Find Full Text PDFNat Immunol
January 2025
Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.
Cell Rep Med
January 2025
Renji-Med-X Clinical Stem Cell Research Center, Renji Hospital, School of Medicine and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200127, China; Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China. Electronic address:
The induction of immunogenic cell death (ICD) impedes tumor progression via both tumor cell-intrinsic and -extrinsic mechanisms, representing a robust therapeutic strategy. However, ICD-targeted therapy remains to be explored and optimized. Through kinome-wide CRISPR-Cas9 screen, NUAK family SNF1-like kinase 1 (NUAK1) is identified as a potential target.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
The Key Laboratory of Mariculture (Ministry of Education), Fisheries College, Ocean University of China, Qingdao 266003, China. Electronic address:
The present study explores the x-box binding protein 1 (xbp1) gene in Haliotis discus hannai (Pacific abalone), focusing on its structure, expression, and functional role under heat stress. Southern blot revealed two copies of xbp1 in the intestine and mantle, one in the gill and muscle, and no detection in the digestive gland. mRNA expression level of xbp1 was highest in the gill, followed by the mantle, intestine, and muscle, with the digestive gland showing the lowest expression.
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