The unfolded protein response (UPR) is composed by homeostatic signaling pathways that are activated by excessive protein misfolding in the endoplasmic reticulum. Ire1 signaling is an important mediator of the UPR, leading to the activation of the transcription factor Xbp1. Here, we show that Drosophila Ire1 mutant photoreceptors have defects in the delivery of rhodopsin-1 to the rhabdomere and in the secretion of Spacemaker/Eyes Shut into the interrhabdomeral space. However, these defects are not observed in Xbp1 mutant photoreceptors. Ire1 mutant retinas have higher mRNA levels for targets of regulated Ire1-dependent decay (RIDD), including for the fatty acid transport protein (fatp). Importantly, the downregulation of fatp by RNAi rescues the rhodopsin-1 delivery defects observed in Ire1 mutant photoreceptors. Our results show that the role of Ire1 during photoreceptor differentiation is independent of Xbp1 function and demonstrate the physiological relevance of the RIDD mechanism in this specific paradigm.
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http://dx.doi.org/10.1016/j.celrep.2013.09.046 | DOI Listing |
Mol Biol Rep
November 2024
Biochemistry and Structural Biology Division, CSIR- Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India.
Background: Endoplasmic reticulum plays a central role in protein folding and cellular detoxification. NEDD4, a HECT E3 ubiquitin ligase, has been implicated in endoplasmic reticulum stress in humans. In this study, we have explored the role of S.
View Article and Find Full Text PDFEMBO J
October 2024
Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria.
Conserved signaling cascades monitor protein-folding homeostasis to ensure proper cellular function. One of the evolutionary conserved key players is IRE1, which maintains endoplasmic reticulum (ER) homeostasis through the unfolded protein response (UPR). Upon accumulation of misfolded proteins in the ER, IRE1 forms clusters on the ER membrane to initiate UPR signaling.
View Article and Find Full Text PDFBiochim Biophys Acta Mol Basis Dis
December 2024
School of Life Sciences, Shaoxing University, Shaoxing, Zhejiang, China; Neurodegeneration and Neuroregeneration Laboratory, Department of Basic Medicine, School of Medicine, Shaoxing University, Shaoxing, Zhejiang, China. Electronic address:
Accumulation in the brain of amyloid-β (Aβ), derived from cleavage of Aβ precursor protein (APP), is a hallmark of Alzheimer's disease (AD). Oleanonic acid (OA), a phytochemical from several plants, has proven anti-inflammatory effects, but its role in AD remains unknown. Here we found that OA reduced APP expression and inhibited oxidative stress via Nrf2/HO-1 signaling in SH-SY5Y neuroblastoma cells stably overexpressing APP.
View Article and Find Full Text PDFPlant Physiol Biochem
October 2024
Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea; Division of Life Science, Division of Applied Life Sciences (BK4 Program) Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea. Electronic address:
The unfolded protein response (UPR) is a crucial cellular mechanism for maintaining protein folding homeostasis during endoplasmic reticulum (ER) stress. In this study, the role of IRE1, a key component of the UPR, was investigated in protein translation regulation under ER stress conditions in Arabidopsis. We discovered that the loss of IRE1A and IRE1B leads to diminished protein translation, indicating a significant role for IRE1 in this process.
View Article and Find Full Text PDFMol Biol Cell
September 2024
Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115.
The unfolded protein response (UPR) detects and mitigates the harmful effects of dysregulated endoplasmic reticulum (ER) function. The UPR has been best characterized as a protein quality control response, and the sole UPR sensor in yeast, Ire1, is known to detect misfolded ER proteins. However, recent work suggests the UPR can also sense diverse defects within the ER membrane, including increased fatty acid saturation and altered phospholipid abundance.
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