Ontology highlight
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PROVIDER: PRJNA474794 | ENA |
REPOSITORIES: ENA
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Project description:The ER membrane protein complex interacts cotranslationally to enable biogenesis of multipass membrane proteins
| PRJNA449388 | ENA
Project description:Sel1L is an adaptor protein for the E3 ligase Hrd1 involved in endoplasmic reticulum-associated degradation (ERAD). Its physiological importance in mammalian ERAD, however, remains to be established. Here, using the inducible Sel1L knockout mouse and cell models, we provide the first in vivo evidence that Sel1L is indispensable for Hrd1 stability, ER homeostasis and survival. Acute loss of Sel1L leads to premature death in adult mice within 3 weeks with profound pancreatic atrophy. Contrary to current belief, our data show that mammalian Sel1L is required for Hrd1 stability and ERAD function both in vitro and in vivo. Sel1L deficiency disturbs ER homeostasis, activates ER stress, attenuates translation and promotes cell death. Serendipitously, using biochemical approach coupled with mass spectrometry, we found that Sel1L deficiency causes the aggregation of both small and large ribosomal subunits. Thus, Sel1L is an indispensable component of mammalian ERAD and ER homeostasis, which is essential for protein translation, pancreatic function, cellular and organismal survival. Pancreas tissue of wild type and inducible Sel1L knockout mice were subjected to gene expression analysis.
2013-12-04 | E-GEOD-52929 | biostudies-arrayexpress
Project description:Vesicular traffic and membrane contact sites between organelles enable the exchange of proteins, lipids, and metabolites. Recruitment of membrane tethers to contact sites between the endoplasmic reticulum (ER) and the plasma membrane is often triggered by calcium. In contrast, we reveal here a function for calcium in the repression of cholesterol export at membrane contact sites between the ER and the Golgi complex. We show that calcium efflux from ER stores induced by inositol-triphosphate [IP3] accumulation upon loss of the inositol 5-phosphatase INPP5A or sustained receptor signaling triggers the depletion of cholesterol and associated complex glycosphingolipids from the cell surface, resulting in a blockade of clathrin-independent endocytosis (CIE) of bacterial Shiga toxin. This phenotype is caused by the calcium-induced dissociation of oxysterol binding protein (OSBP) from the Golgi complex and from VAP-containing membrane contact sites. Our findings reveal a crucial function for INPP5A-mediated IP3 hydrolysis in the control of lipid exchange at membrane contact sites.
2021-05-06 | MTBLS2444 | MetaboLights
Project description:To dissect the requirements of membrane protein degradation from the ER, we expressed the mouse major histocompatibility complex class I heavy chain H-2K(b) in yeast. Like other proteins degraded from the ER, unassembled H-2K(b) heavy chains are not transported to the Golgi but are degraded in a proteasome-dependent manner. The overexpression of H-2K(b) heavy chains induces the unfolded protein response (UPR). In yeast mutants unable to mount the UPR, H-2K(b) heavy chains are greatly stabilized. This defect in degradation is suppressed by the expression of the active form of Hac1p, the transcription factor that upregulates UPR-induced genes. These results indicate that induction of the UPR is required for the degradation of protein substrates from the ER.
2005-06-28 | E-SMDB-1576 | biostudies-arrayexpress
Project description:Patient-derived organoids and cellular spheroids recapitulate tissue physiology with remarkable fidelity. We investigated how engagement with a reconstituted basement membrane (rBM) in three dimensions (3D) supports the polarized, stress resilient tissue phenotype of mammary epithelial spheroids. Cells interacting with rBM in 3D had reduced levels of total and actin-associated filamin and decreased cortical actin tension that increased plasma membrane protrusions to promote negative plasma membrane curvature and plasma membrane protein associations linked to protein secretion. By contrast, cells engaging rBM in 2D had high cortical actin tension that forced filamin unfolding and endoplasmic reticulum (ER) associations. Enhanced filamin-ER interactions increased levels of PKR-like ER kinase effectors and ER-plasma membrane contact sites that compromised calcium homeostasis and diminished cell viability. Consequently, cells with low cortical actin tension had reduced ER stress and survived better. Consistently, cortical actin tension in cellular spheroids regulated polarized BM membrane deposition and sensitivity to exogenous stress. The findings implicate cortical actin tension-mediated filamin unfolding in ER function, and underscore the importance of tissue mechanics in organoid homeostasis.
2022-06-08 | GSE150695 | GEO
Project description:To dissect the requirements of membrane protein degradation from the ER, we expressed the mouse major histocompatibility complex class I heavy chain H-2K(b) in yeast. Like other proteins degraded from the ER, unassembled H-2K(b) heavy chains are not transported to the Golgi but are degraded in a proteasome-dependent manner. The overexpression of H-2K(b) heavy chains induces the unfolded protein response (UPR). In yeast mutants unable to mount the UPR, H-2K(b) heavy chains are greatly stabilized. This defect in degradation is suppressed by the expression of the active form of Hac1p, the transcription factor that upregulates UPR-induced genes. These results indicate that induction of the UPR is required for the degradation of protein substrates from the ER. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed
2005-08-16 | E-GEOD-3130 | biostudies-arrayexpress
Project description:Aspergillus fumigatus is a human-pathogenic mold that extracts nutrients from the environment or from host tissues by secreting hydrolytic enzymes. The ability of A. fumigatus to adjust secretion levels in proportion to demand relies on the assistance of the unfolded protein response (UPR), an adaptive stress response pathway that regulates the unique protein-folding environment of the endoplasmic reticulum (ER). The P5-type ATPase Spf1 has recently been implicated in a novel mechanism of ER homeostasis that involves correcting errors in ER-membrane protein targeting. However, the contribution of this protein to the biology of A. fumigatus is unknown. Here, we employed a gene knockout and RNA sequencing strategy to determine the functional role of the A. fumigatus gene coding for the orthologous P5 ATPase SpfA. The data reveal that the spfA gene is induced by ER stress in a UPR-dependent manner. In the absence of spfA, the A. fumigatus transcriptome shifts toward a profile of altered redox and lipid balance, in addition to a signature of ER stress that includes srcA, encoding a second P-type ATPase in the ER. A DspfA deletion mutant showed increased sensitivity to ER stress, oxidative stress, and antifungal drugs that target the cell wall or plasma membrane. The combined loss of spfA and srcA exacerbated these phenotypes and attenuated virulence in two animal infection models. These findings demonstrate that the ER-resident ATPases SpfA and SrcA act jointly to support diverse adaptive functions of the ER that are necessary for fitness in the host environment.
2021-10-05 | GSE179173 | GEO
Project description:Estrogen receptor (ER) binds to distal enhancers within the genome and requires additional factors, such as the Forkhead protein FoxA1, for mediating chromatin interactions. We now show that the human Groucho protein, Transducin-like enhancer protein 1 (TLE1), positively assists some ER-chromatin interactions, a role that is distinct from its general role as a transcriptional repressor. We show that specific silencing of TLE1 inhibits the ability of ER to bind to a subset of ER binding sites within the genome, a phenomenon that results in perturbations in phospho-RNA Pol II recruitment. Furthermore, TLE1 is essential for effective ER-mediated cell division. We have discovered a distinct role for TLE1, as a necessary transcriptional component of the ER complex, where it facilitates ER-chromatin interactions.
2012-11-14 | E-MTAB-1368 | biostudies-arrayexpress
Project description:The endoplasmic reticulum (ER) was implicated as the site of microRNA (miRNA)-mediated translation repression in plants. Here, we examined the ER- and rough ER-associated small RNAome, transcriptome and translatome. We found that almost all cellular transcripts were present on membrane-bound polysomes (MBPs), and miRNAs were enriched in membranes and on MBPs. miRNAs were recruited to membranes by their effector protein AGO1, whereas AGO1 associated with membranes and, partly ribosomes, in an RNA-independent manner. Most strikingly, 22 ntmiRNA isoformsand a set of 22 ntsiRNAs, were enriched in the membrane fraction and onMBPs, where they trigger phasedsecondary siRNAproduction from target transcripts. Loss of membrane association of the 22 nt small RNAs resulted in the loss of phasing in secondary siRNA production.These findings point to the ER as a hub that hosts and organizes endogenous small RNAs in plants.
2016-12-23 | GSE82039 | GEO
Project description:Endoplasmic reticulum-associated degradation (ERAD) represents a principle quality control (QC) mechanism to clear misfolded proteins in the ER; however, its physiological significance and the nature of endogenous ERAD substrates remain largely unknown. Here we discover that IRE1alpha, the sensor of unfolded protein response (UPR), is a bona fide substrate of the Sel1L-Hrd1 ERAD complex. Mechanistically, ERAD-mediated IRE1alpha degradation occurs in a Bip-dependent manner under basal conditions and is attenuated in response to ER stress. Both intramembrane hydrophilic residues of IRE1alpha and lectin protein OS9 are required for IRE1alpha degradation. ERAD deficiency causes IRE1alpha protein stabilization, accumulation and mild activation both in vitro and in vivo, leading to cellular hypersensitivity to ER stress and inflammation. Furthermore, though enterocyte-specific Sel1L-knockout mice (Sel1LÎ?IEC) are viable and appear normal, they are more susceptible to experimental colitis in an IRE1alpha-dependent but CHOP-independent manner. Collectively, these results demonstrate that Sel1L-Hrd1 ERAD serves a distinct, essential function in restraint of IRE1alpha signaling in vivo by managing its protein turnover. Colon epithelium of wild type and enterocyte-specific Sel1L knockout mice were subjected to gene expression analysis.
2015-11-04 | E-GEOD-70563 | biostudies-arrayexpress