1
|
Fan LL, Fang H, Zheng JY, Qiu YH, Wu GL, Cai YF, Chen YB, Zhang SJ. Taohong Siwu decoction alleviates cognitive impairment by suppressing endoplasmic reticulum stress and apoptosis signaling pathway in vascular dementia rats. JOURNAL OF ETHNOPHARMACOLOGY 2024; 333:118407. [PMID: 38824979 DOI: 10.1016/j.jep.2024.118407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 05/27/2024] [Accepted: 05/28/2024] [Indexed: 06/04/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Taohong Siwu Decoction (TSD), a classic traditional Chinese medicine formula, is used for the treatment of vascular diseases, including vascular dementia (VD). However, the mechanisms remain unclear. AIM OF STUDY This study aimed to investigate whether TSD has a positive effect on cognitive impairment in VD rats and to confirm that the mechanism of action is related to the Endoplasmic Reticulum stress (ERs) and cell apoptosis signaling pathway. MATERIALS AND METHODS A total of 40 male adult Sprague-Dawley rats were divided into four groups: sham-operated group (Sham), the two-vessel occlusion group (2VO), the 2VO treated with 4.5 g/kg/d TSD group (2VO + TSD-L), the 2VO treated with 13.5 g/kg/d TSD group (2VO + TSD-H). The rats underwent either 2VO surgery or sham surgery. Postoperative TSD treatment was given for 4 consecutive weeks. Behavioral tests were initiated at the end of gastrulation. Open-field test (OFT) was used to detect the activity level. The New Object Recognition test (NOR) was used to test long-term memory. The Morris water maze (MWM) test was used to examine the foundation of spatial learning and memory. As a final step, the hippocampus was taken for molecular testing. The protein levels of GRP78 (Bip), p-PERK, PERK, IRE1α, p-IRE1α, ATF6, eIF2α, p-eIF2α, ATF4, XBP1, Bcl-2 and Bax were determined by Western blot. Immunofluorescence visualizes molecular expression. RESULTS In the OFT, residence time in the central area was significantly longer in both TSD treatment groups compared to the 2VO group. In the NOR, the recognition index was obviously elevated in both TSD treatment groups. The 2VO group had a significantly longer escape latency and fewer times in crossing the location of the platform compared with the Sham group in MWM. TSD treatment reversed this notion. Pathologically, staining observations confirmed that TSD inhibited hippocampal neuronal loss and alleviated the abnormal reduction of the Nissl body. In parallel, TUNEL staining illustrated that TSD decelerated neuronal apoptosis. Western Blot demonstrated that TSD reduces the expression of ERs and apoptotic proteins. CONCLUSION In this study, the significant ameliorative effect on cognitive impairment of TSD has been determined by comparing the behavioral data of the 4 groups of rats. Furthermore, it was confirmed that this effect of TSD was achieved by suppressing the ERs-mediated apoptosis signaling pathway.
Collapse
Affiliation(s)
- Ling-Ling Fan
- State Key Laboratory of Traditional Chinese Medicine Syndrome, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou 510405, China; Department of Neurology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China; Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China; Guangdong Provincial Key Laboratory of Research on Emergency in TCM Guangzhou, 510000, China; Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510000, China
| | - Hao Fang
- Department of Neurology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China; Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China
| | - Jia-Yi Zheng
- Department of Neurology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China; Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China
| | - Yu-Hui Qiu
- Department of Neurology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China; Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China
| | - Guang-Liang Wu
- Department of Neurology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China; Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China; Guangdong Provincial Key Laboratory of Research on Emergency in TCM Guangzhou, 510000, China
| | - Ye-Feng Cai
- State Key Laboratory of Traditional Chinese Medicine Syndrome, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou 510405, China; Department of Neurology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China; Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China; Guangdong Provincial Key Laboratory of Research on Emergency in TCM Guangzhou, 510000, China.
| | - Yun-Bo Chen
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, 510000, China.
| | - Shi-Jie Zhang
- State Key Laboratory of Traditional Chinese Medicine Syndrome, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou 510405, China; Department of Neurology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China; Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China; Guangdong Provincial Key Laboratory of Research on Emergency in TCM Guangzhou, 510000, China.
| |
Collapse
|
2
|
Dawes S, Hurst N, Grey G, Wieteska L, Wright NV, Manfield IW, Hussain MH, Kalverda AP, Lewandowski JR, Chen B, Zhuravleva A. Chaperone BiP controls ER stress sensor Ire1 through interactions with its oligomers. Life Sci Alliance 2024; 7:e202402702. [PMID: 39103227 PMCID: PMC11300964 DOI: 10.26508/lsa.202402702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 07/24/2024] [Accepted: 07/24/2024] [Indexed: 08/07/2024] Open
Abstract
The complex multistep activation cascade of Ire1 involves changes in the Ire1 conformation and oligomeric state. Ire1 activation enhances ER folding capacity, in part by overexpressing the ER Hsp70 molecular chaperone BiP; in turn, BiP provides tight negative control of Ire1 activation. This study demonstrates that BiP regulates Ire1 activation through a direct interaction with Ire1 oligomers. Particularly, we demonstrated that the binding of Ire1 luminal domain (LD) to unfolded protein substrates not only trigger conformational changes in Ire1-LD that favour the formation of Ire1-LD oligomers but also exposes BiP binding motifs, enabling the molecular chaperone BiP to directly bind to Ire1-LD in an ATP-dependent manner. These transient interactions between BiP and two short motifs in the disordered region of Ire1-LD are reminiscent of interactions between clathrin and another Hsp70, cytoplasmic Hsc70. BiP binding to substrate-bound Ire1-LD oligomers enables unfolded protein substrates and BiP to synergistically and dynamically control Ire1-LD oligomerisation, helping to return Ire1 to its deactivated state when an ER stress response is no longer required.
Collapse
Affiliation(s)
- Sam Dawes
- https://ror.org/024mrxd33 School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
- Chemistry Department, University of Sheffield, Sheffield, UK
| | - Nicholas Hurst
- https://ror.org/024mrxd33 School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Gabriel Grey
- https://ror.org/024mrxd33 School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Lukasz Wieteska
- https://ror.org/024mrxd33 School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Nathan V Wright
- https://ror.org/024mrxd33 School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Iain W Manfield
- https://ror.org/024mrxd33 School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Mohammed H Hussain
- https://ror.org/024mrxd33 School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Arnout P Kalverda
- https://ror.org/024mrxd33 School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | | | - Beining Chen
- Chemistry Department, University of Sheffield, Sheffield, UK
| | - Anastasia Zhuravleva
- https://ror.org/024mrxd33 School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| |
Collapse
|
3
|
Prince S, Maguemoun K, Ferdebouh M, Querido E, Derumier A, Tremblay S, Chartrand P. CoPixie, a novel algorithm for single-particle track colocalization, enables efficient quantification of telomerase dynamics at telomeres. Nucleic Acids Res 2024; 52:9417-9430. [PMID: 39082280 PMCID: PMC11381360 DOI: 10.1093/nar/gkae669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 07/16/2024] [Accepted: 07/22/2024] [Indexed: 09/10/2024] Open
Abstract
Single-particle imaging and tracking can be combined with colocalization analysis to study the dynamic interactions between macromolecules in living cells. Indeed, single-particle tracking has been extensively used to study protein-DNA interactions and dynamics. Still, unbiased identification and quantification of binding events at specific genomic loci remains challenging. Herein, we describe CoPixie, a new software that identifies colocalization events between a theoretically unlimited number of imaging channels, including single-particle movies. CoPixie is an object-based colocalization algorithm that relies on both pixel and trajectory overlap to determine colocalization between molecules. We employed CoPixie with live-cell single-molecule imaging of telomerase and telomeres, to test the model that cancer-associated POT1 mutations facilitate telomere accessibility. We show that POT1 mutants Y223C, D224N or K90E increase telomere accessibility for telomerase interaction. However, unlike the POT1-D224N mutant, the POT1-Y223C and POT1-K90E mutations also increase the duration of long-lasting telomerase interactions at telomeres. Our data reveal that telomere elongation in cells expressing cancer-associated POT1 mutants arises from the dual impact of these mutations on telomere accessibility and telomerase retention at telomeres. CoPixie can be used to explore a variety of questions involving macromolecular interactions in living cells, including between proteins and nucleic acids, from multicolor single-particle tracks.
Collapse
Affiliation(s)
- Samuel Prince
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Kamélia Maguemoun
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Mouna Ferdebouh
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Emmanuelle Querido
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Amélie Derumier
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Stéphanie Tremblay
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Pascal Chartrand
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| |
Collapse
|
4
|
Kettel P, Marosits L, Spinetti E, Rechberger M, Giannini C, Radler P, Niedermoser I, Fischer I, Versteeg GA, Loose M, Covino R, Karagöz GE. Disordered regions in the IRE1α ER lumenal domain mediate its stress-induced clustering. EMBO J 2024:10.1038/s44318-024-00207-0. [PMID: 39232130 DOI: 10.1038/s44318-024-00207-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/02/2024] [Accepted: 07/23/2024] [Indexed: 09/06/2024] Open
Abstract
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. What regulates IRE1 cluster formation is not fully understood. Here, we show that the ER lumenal domain (LD) of human IRE1α forms biomolecular condensates in vitro. IRE1α LD condensates were stabilized both by binding to unfolded polypeptides as well as by tethering to model membranes, suggesting their role in assembling IRE1α into signaling-competent stable clusters. Molecular dynamics simulations indicated that weak multivalent interactions drive IRE1α LD clustering. Mutagenesis experiments identified disordered regions in IRE1α LD to control its clustering in vitro and in cells. Importantly, dysregulated clustering of IRE1α mutants led to defects in IRE1α signaling. Our results revealed that disordered regions in IRE1α LD control its clustering and suggest their role as a common strategy in regulating protein assembly on membranes.
Collapse
Affiliation(s)
- Paulina Kettel
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Laura Marosits
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria
- Medical University of Vienna, Vienna, Austria
| | - Elena Spinetti
- Frankfurt Institute for Advanced Studies, Frankfurt, Germany
- Institute of Biophysics, Goethe University, Frankfurt, Germany
| | | | - Caterina Giannini
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Philipp Radler
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Isabell Niedermoser
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria
- Medical University of Vienna, Vienna, Austria
| | - Irmgard Fischer
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria
| | - Gijs A Versteeg
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria
- Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Martin Loose
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Roberto Covino
- Frankfurt Institute for Advanced Studies, Frankfurt, Germany
- IMPRS on Cellular Biophysics, Frankfurt, Germany
| | - G Elif Karagöz
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria.
- Medical University of Vienna, Vienna, Austria.
| |
Collapse
|
5
|
Orsi A, van Anken E, Vitale M, Zamai M, Caiolfa VR, Sitia R, Bakunts A. Congress of multiple dimers is needed for cross-phosphorylation of IRE1α and its RNase activity. Life Sci Alliance 2024; 7:e202302562. [PMID: 38886017 PMCID: PMC11184514 DOI: 10.26508/lsa.202302562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 05/24/2024] [Accepted: 06/03/2024] [Indexed: 06/20/2024] Open
Abstract
The unfolded protein response can switch from a pro-survival to a maladaptive, pro-apoptotic mode. During ER stress, IRE1α sensors dimerize, become phosphorylated, and activate XBP1 splicing, increasing folding capacity in the ER protein factory. The steps that turn on the IRE1α endonuclease activity against endogenous mRNAs during maladaptive ER stress are still unknown. Here, we show that although necessary, IRE1α dimerization is not sufficient to trigger phosphorylation. Random and/or guided collisions among IRE1α dimers are needed to elicit cross-phosphorylation and endonuclease activities. Thus, reaching a critical concentration of IRE1α dimers in the ER membrane is a key event. Formation of stable IRE1α clusters is not necessary for RNase activity. However, clustering could modulate the potency of the response, promoting interactions between dimers and decreasing the accessibility of phosphorylated IRE1α to phosphatases. The stepwise activation of IRE1α molecules and their low concentration at the steady state prevent excessive responses, unleashing full-blown IRE1 activity only upon intense stress conditions.
Collapse
Affiliation(s)
- Andrea Orsi
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Eelco van Anken
- https://ror.org/01gmqr298 Division of Genetics and Cell Biology, Vita-Salute San Raffaele University, Milan, Italy
| | - Milena Vitale
- https://ror.org/01gmqr298 Division of Genetics and Cell Biology, Vita-Salute San Raffaele University, Milan, Italy
| | - Moreno Zamai
- Unit of Microscopy and Dynamic Imaging, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Valeria R Caiolfa
- Unit of Microscopy and Dynamic Imaging, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Center for Experimental Imaging, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Roberto Sitia
- https://ror.org/01gmqr298 Division of Genetics and Cell Biology, Vita-Salute San Raffaele University, Milan, Italy
| | - Anush Bakunts
- https://ror.org/01gmqr298 Division of Genetics and Cell Biology, Vita-Salute San Raffaele University, Milan, Italy
| |
Collapse
|
6
|
Ernst R, Renne MF, Jain A, von der Malsburg A. Endoplasmic Reticulum Membrane Homeostasis and the Unfolded Protein Response. Cold Spring Harb Perspect Biol 2024; 16:a041400. [PMID: 38253414 PMCID: PMC11293554 DOI: 10.1101/cshperspect.a041400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The endoplasmic reticulum (ER) is the key organelle for membrane biogenesis. Most lipids are synthesized in the ER, and most membrane proteins are first inserted into the ER membrane before they are transported to their target organelle. The composition and properties of the ER membrane must be carefully controlled to provide a suitable environment for the insertion and folding of membrane proteins. The unfolded protein response (UPR) is a powerful signaling pathway that balances protein and lipid production in the ER. Here, we summarize our current knowledge of how aberrant compositions of the ER membrane, referred to as lipid bilayer stress, trigger the UPR.
Collapse
Affiliation(s)
- Robert Ernst
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, 66421 Homburg, Germany
- Preclinical Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Mike F Renne
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, 66421 Homburg, Germany
- Preclinical Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Aamna Jain
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, 66421 Homburg, Germany
- Preclinical Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Alexander von der Malsburg
- Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, 66421 Homburg, Germany
- Preclinical Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg, Germany
| |
Collapse
|
7
|
Dukic B, Ruppert Z, Tóth ME, Hunya Á, Czibula Á, Bíró P, Tiszlavicz Á, Péter M, Balogh G, Erdélyi M, Timinszky G, Vígh L, Gombos I, Török Z. Mild Hyperthermia-Induced Thermogenesis in the Endoplasmic Reticulum Defines Stress Response Mechanisms. Cells 2024; 13:1141. [PMID: 38994992 PMCID: PMC11240596 DOI: 10.3390/cells13131141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 06/24/2024] [Accepted: 06/27/2024] [Indexed: 07/13/2024] Open
Abstract
Previous studies reported that a mild, non-protein-denaturing, fever-like temperature increase induced the unfolded protein response (UPR) in mammalian cells. Our dSTORM super-resolution microscopy experiments revealed that the master regulator of the UPR, the IRE1 (inositol-requiring enzyme 1) protein, is clustered as a result of UPR activation in a human osteosarcoma cell line (U2OS) upon mild heat stress. Using ER thermo yellow, a temperature-sensitive fluorescent probe targeted to the endoplasmic reticulum (ER), we detected significant intracellular thermogenesis in mouse embryonic fibroblast (MEF) cells. Temperatures reached at least 8 °C higher than the external environment (40 °C), resulting in exceptionally high ER temperatures similar to those previously described for mitochondria. Mild heat-induced thermogenesis in the ER of MEF cells was likely due to the uncoupling of the Ca2+/ATPase (SERCA) pump. The high ER temperatures initiated a pronounced cytosolic heat-shock response in MEF cells, which was significantly lower in U2OS cells in which both the ER thermogenesis and SERCA pump uncoupling were absent. Our results suggest that depending on intrinsic cellular properties, mild hyperthermia-induced intracellular thermogenesis defines the cellular response mechanism and determines the outcome of hyperthermic stress.
Collapse
Affiliation(s)
- Barbara Dukic
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
- Doctoral School of Environmental Sciences, Faculty of Science and Informatics, University of Szeged, 6720 Szeged, Hungary
| | - Zsófia Ruppert
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
- Doctoral School of Biology, Faculty of Science and Informatics, University of Szeged, 6720 Szeged, Hungary
| | - Melinda E Tóth
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Ákos Hunya
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Ágnes Czibula
- Laboratory of DNA Damage and Nuclear Dynamics, Institute of Genetics, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
- Department of Immunology, University of Szeged, 6720 Szeged, Hungary
| | - Péter Bíró
- Department of Optics and Quantum Electronics, University of Szeged, 6720 Szeged, Hungary
| | - Ádám Tiszlavicz
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Mária Péter
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Gábor Balogh
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Miklós Erdélyi
- Department of Optics and Quantum Electronics, University of Szeged, 6720 Szeged, Hungary
| | - Gyula Timinszky
- Laboratory of DNA Damage and Nuclear Dynamics, Institute of Genetics, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - László Vígh
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Imre Gombos
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| | - Zsolt Török
- Laboratory of Molecular Stress Biology, Institute of Biochemistry, HUN-REN Biological Research Centre, 6726 Szeged, Hungary
| |
Collapse
|
8
|
Kettel P, Karagöz GE. Endoplasmic reticulum: Monitoring and maintaining protein and membrane homeostasis in the endoplasmic reticulum by the unfolded protein response. Int J Biochem Cell Biol 2024; 172:106598. [PMID: 38768891 DOI: 10.1016/j.biocel.2024.106598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/01/2024] [Accepted: 05/14/2024] [Indexed: 05/22/2024]
Abstract
The endoplasmic reticulum (ER) regulates essential cellular processes, including protein folding, lipid synthesis, and calcium homeostasis. The ER homeostasis is maintained by a conserved set of signaling cascades called the Unfolded Protein Response (UPR). How the UPR senses perturbations in ER homeostasis has been the subject of active research for decades. In metazoans, the UPR consists of three ER-membrane embedded sensors: IRE1, PERK and ATF6. These sensors detect the accumulation of misfolded proteins in the ER lumen and adjust protein folding capacity according to cellular needs. Early work revealed that the ER-resident chaperone BiP binds to all three UPR sensors in higher eukaryotes and BiP binding was suggested to regulate their activity. More recent data have shown that in higher eukaryotes the interaction of the UPR sensors with a complex network of chaperones and misfolded proteins modulates their activation and deactivation dynamics. Furthermore, emerging evidence suggests that the UPR monitors ER membrane integrity beyond protein folding defects. However, the mechanistic and structural basis of UPR activation by proteotoxic and lipid bilayer stress in higher eukaryotes remains only partially understood. Here, we review the current understanding of novel protein interaction networks and the contribution of the lipid membrane environment to UPR activation.
Collapse
Affiliation(s)
- Paulina Kettel
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - G Elif Karagöz
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria; Medical University of Vienna, Vienna, Austria.
| |
Collapse
|
9
|
Simpson MS, De Luca H, Cauthorn S, Luong P, Udeshi ND, Svinkina T, Schmieder SS, Carr SA, Grey MJ, Lencer WI. IRE1α recognizes a structural motif in cholera toxin to activate an unfolded protein response. J Cell Biol 2024; 223:e202402062. [PMID: 38578285 PMCID: PMC10996581 DOI: 10.1083/jcb.202402062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 04/06/2024] Open
Abstract
IRE1α is an endoplasmic reticulum (ER) sensor that recognizes misfolded proteins to induce the unfolded protein response (UPR). We studied cholera toxin (CTx), which invades the ER and activates IRE1α in host cells, to understand how unfolded proteins are recognized. Proximity labeling colocalized the enzymatic and metastable A1 segment of CTx (CTxA1) with IRE1α in live cells, where we also found that CTx-induced IRE1α activation enhanced toxicity. In vitro, CTxA1 bound the IRE1α lumenal domain (IRE1αLD), but global unfolding was not required. Rather, the IRE1αLD recognized a seven-residue motif within an edge β-strand of CTxA1 that must locally unfold for binding. Binding mapped to a pocket on IRE1αLD normally occupied by a segment of the IRE1α C-terminal flexible loop implicated in IRE1α oligomerization. Mutation of the CTxA1 recognition motif blocked CTx-induced IRE1α activation in live cells, thus linking the binding event with IRE1α signal transduction and induction of the UPR.
Collapse
Affiliation(s)
- Mariska S. Simpson
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
- Graduate School of Life Sciences, Utrecht University, Utrecht, Netherlands
| | - Heidi De Luca
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
| | - Sarah Cauthorn
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Phi Luong
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
| | | | | | - Stefanie S. Schmieder
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | | | - Michael J. Grey
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Harvard Digestive Disease Center, Boston, MA, USA
| | - Wayne I. Lencer
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children’s Hospital, Boston MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Harvard Digestive Disease Center, Boston, MA, USA
| |
Collapse
|
10
|
Pontisso I, Ornelas-Guevara R, Chevet E, Combettes L, Dupont G. Gradual ER calcium depletion induces a progressive and reversible UPR signaling. PNAS NEXUS 2024; 3:pgae229. [PMID: 38933930 PMCID: PMC11200134 DOI: 10.1093/pnasnexus/pgae229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 05/29/2024] [Indexed: 06/28/2024]
Abstract
The unfolded protein response (UPR) is a widespread signal transduction pathway triggered by endoplasmic reticulum (ER) stress. Because calcium (Ca2+) is a key factor in the maintenance of ER homeostasis, massive Ca2+ depletion of the ER is a potent inducer of ER stress. Although moderate changes in ER Ca2+ drive the ubiquitous Ca2+ signaling pathways, a possible incremental relationship between UPR activation and Ca2+ changes has yet to be described. Here, we determine the sensitivity and time-dependency of activation of the three ER stress sensors, inositol-requiring protein 1 alpha (IRE1α), protein kinase R-like ER kinase (PERK), and activating transcription factor 6 alpha (ATF6α) in response to controlled changes in the concentration of ER Ca2+ in human cultured cells. Combining Ca2+ imaging, fluorescence recovery after photobleaching experiments, biochemical analyses, and mathematical modeling, we uncover a nonlinear rate of activation of the IRE1α branch of UPR, as compared to the PERK and ATF6α branches that become activated gradually with time and are sensitive to more important ER Ca2+ depletions. However, the three arms are all activated within a 1 h timescale. The model predicted the deactivation of PERK and IRE1α upon refilling the ER with Ca2+. Accordingly, we showed that ER Ca2+ replenishment leads to the complete reversion of IRE1α and PERK phosphorylation in less than 15 min, thus revealing the highly plastic character of the activation of the upstream UPR sensors. In conclusion, our results reveal a dynamic and dose-sensitive Ca2+-dependent activation/deactivation cycle of UPR induction, which could tightly control cell fate upon acute and/or chronic stress.
Collapse
Affiliation(s)
- Ilaria Pontisso
- U1282 “Calcium Signaling and Microbial Infections”, Institut de Biologie Intégrative de la Cellule (I2BC)—Université Paris-Saclay, Gif-Sur-Yvette 91190, France
| | - Roberto Ornelas-Guevara
- Unit of Theoretical Chronobiology, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
| | - Eric Chevet
- Inserm U1242 Université de Rennes, 35000 Rennes, France
- Centre de Lutte Contre le Cancer Eugène Marquis, 35042 Rennes, France
| | - Laurent Combettes
- U1282 “Calcium Signaling and Microbial Infections”, Institut de Biologie Intégrative de la Cellule (I2BC)—Université Paris-Saclay, Gif-Sur-Yvette 91190, France
| | - Geneviève Dupont
- Unit of Theoretical Chronobiology, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
| |
Collapse
|
11
|
Liu S, Zhang X, Yao X, Wang G, Huang S, Chen P, Tang M, Cai J, Wu Z, Zhang Y, Xu R, Liu K, He K, Wang Y, Jiang L, Wang QA, Rui L, Liu J, Liu Y. Mammalian IRE1α dynamically and functionally coalesces with stress granules. Nat Cell Biol 2024; 26:917-931. [PMID: 38714852 DOI: 10.1038/s41556-024-01418-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 04/03/2024] [Indexed: 05/31/2024]
Abstract
Upon endoplasmic reticulum (ER) stress, activation of the ER-resident transmembrane protein kinase/endoribonuclease inositol-requiring enzyme 1 (IRE1) initiates a key branch of the unfolded protein response (UPR) through unconventional splicing generation of the transcription factor X-box-binding protein 1 (XBP1s). Activated IRE1 can form large clusters/foci, whose exact dynamic architectures and functional properties remain largely elusive. Here we report that, in mammalian cells, formation of IRE1α clusters is an ER membrane-bound phase separation event that is coupled to the assembly of stress granules (SGs). In response to different stressors, IRE1α clusters are dynamically tethered to SGs at the ER. The cytosolic linker portion of IRE1α possesses intrinsically disordered regions and is essential for its condensation with SGs. Furthermore, disruption of SG assembly abolishes IRE1α clustering and compromises XBP1 mRNA splicing, and such IRE1α-SG coalescence engenders enrichment of the biochemical components of the pro-survival IRE1α-XBP1 pathway during ER stress. Our findings unravel a phase transition mechanism for the spatiotemporal assembly of IRE1α-SG condensates to establish a more efficient IRE1α machinery, thus enabling higher stress-handling capacity.
Collapse
Affiliation(s)
- Songzi Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Xiaoge Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Xin Yao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Guan Wang
- Comprehensive Cancer Center, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, USA
- Department of Molecular & Cellular Endocrinology, Diabetes & Metabolism Research Institute, City of Hope Medical Center, Duarte, CA, USA
| | - Shijia Huang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Peng Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Mingliang Tang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Jie Cai
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
- Clinical Research Center, the Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Zhuyin Wu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Yiliang Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Rongzhi Xu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Kai Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Kangmin He
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yan Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China
| | - Lei Jiang
- Comprehensive Cancer Center, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, USA
- Department of Molecular & Cellular Endocrinology, Diabetes & Metabolism Research Institute, City of Hope Medical Center, Duarte, CA, USA
| | - Qiong A Wang
- Comprehensive Cancer Center, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, USA
- Department of Molecular & Cellular Endocrinology, Diabetes & Metabolism Research Institute, City of Hope Medical Center, Duarte, CA, USA
| | - Liangyou Rui
- Department of Molecular and Integrative Physiology, the University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jianmiao Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science and Technology, Wuhan, China
| | - Yong Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences; TaiKang Center for Life and Medical Sciences; the Institute for Advanced Studies; Frontier Science Center for Immunology and Metabolism, Wuhan University, Wuhan, China.
| |
Collapse
|
12
|
Pincus D, Oakes SA. Unfolding emergency calls stress granules to the ER. Nat Cell Biol 2024; 26:845-846. [PMID: 38822214 DOI: 10.1038/s41556-024-01434-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Affiliation(s)
- David Pincus
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, USA.
| | - Scott A Oakes
- Department of Pathology, University of Chicago, Chicago, IL, USA.
| |
Collapse
|
13
|
McFadden MJ, Reynolds MB, Michmerhuizen BC, Ólafsson EB, Anderson FM, Schultz TL, O’Riordan MX, O’Meara TR. Non-canonical activation of IRE1α during Candida albicans infection enhances macrophage fungicidal activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.02.560560. [PMID: 37873171 PMCID: PMC10592910 DOI: 10.1101/2023.10.02.560560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
While the canonical function of IRE1α is to detect misfolded proteins and activate the unfolded protein response (UPR) to maintain cellular homeostasis, microbial pathogens can also activate IRE1α, which modulates innate immunity and infection outcomes. However, how infection activates IRE1α and its associated inflammatory functions have not been fully elucidated. Recognition of microbe-associated molecular patterns can activate IRE1α, but it is unclear whether this depends on protein misfolding. Here, we report that a common and deadly fungal pathogen, Candida albicans, activates macrophage IRE1α through C-type lectin receptor signaling, reinforcing a role for IRE1α as a central regulator of host responses to infection by a broad range of pathogens. This activation did not depend on protein misfolding in response to C. albicans infection. Moreover, lipopolysaccharide treatment was also able to activate IRE1α prior to protein misfolding, suggesting that pathogen-mediated activation of IRE1α occurs through non-canonical mechanisms. During C. albicans infection, we observed that IRE1α activity promotes phagolysosomal fusion that supports the fungicidal activity of macrophages. Consequently, macrophages lacking IRE1α activity displayed inefficient phagosome maturation, enabling C. albicans to lyse the phagosome, evade fungal killing, and drive aberrant inflammatory cytokine production. Mechanistically, we show that IRE1α activity supports phagosomal calcium flux after phagocytosis of C. albicans, which is crucial for phagosome maturation. Importantly, deletion of IRE1α activity decreased the fungicidal activity of phagocytes in vivo during systemic C. albicans infection. Together, these data provide mechanistic insight for the non-canonical activation of IRE1α during infection, and reveal central roles for IRE1α in macrophage antifungal responses.
Collapse
Affiliation(s)
- Michael J. McFadden
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Mack B. Reynolds
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Einar B. Ólafsson
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Faith M. Anderson
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Tracey L. Schultz
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Mary X.D. O’Riordan
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Teresa R. O’Meara
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| |
Collapse
|
14
|
Le Goupil S, Laprade H, Aubry M, Chevet E. Exploring the IRE1 interactome: From canonical signaling functions to unexpected roles. J Biol Chem 2024; 300:107169. [PMID: 38494075 PMCID: PMC11007444 DOI: 10.1016/j.jbc.2024.107169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 03/04/2024] [Accepted: 03/08/2024] [Indexed: 03/19/2024] Open
Abstract
The unfolded protein response is a mechanism aiming at restoring endoplasmic reticulum (ER) homeostasis and is likely involved in other adaptive pathways. The unfolded protein response is transduced by three proteins acting as sensors and triggering downstream signaling pathways. Among them, inositol-requiring enzyme 1 alpha (IRE1α) (referred to as IRE1 hereafter), an endoplasmic reticulum-resident type I transmembrane protein, exerts its function through both kinase and endoribonuclease activities, resulting in both X-box binding protein 1 mRNA splicing and RNA degradation (regulated ire1 dependent decay). An increasing number of studies have reported protein-protein interactions as regulators of these signaling mechanisms, and additionally, driving other noncanonical functions. In this review, we deliver evolutive and structural insights on IRE1 and further describe how this protein interaction network (interactome) regulates IRE1 signaling abilities or mediates other cellular processes through catalytic-independent mechanisms. Moreover, we focus on newly discovered targets of IRE1 kinase activity and discuss potentially novel IRE1 functions based on the nature of the interactome, thereby identifying new fields to explore regarding this protein's biological roles.
Collapse
Affiliation(s)
- Simon Le Goupil
- INSERM U1242, University of Rennes, Rennes, France; Centre de Lutte contre le cancer Eugène Marquis, Rennes, France.
| | - Hadrien Laprade
- INSERM U1242, University of Rennes, Rennes, France; Centre de Lutte contre le cancer Eugène Marquis, Rennes, France
| | - Marc Aubry
- INSERM U1242, University of Rennes, Rennes, France; Centre de Lutte contre le cancer Eugène Marquis, Rennes, France
| | - Eric Chevet
- INSERM U1242, University of Rennes, Rennes, France; Centre de Lutte contre le cancer Eugène Marquis, Rennes, France
| |
Collapse
|
15
|
Le Saux CJ, Ho TC, Brumwell AM, Kathiriya JJ, Wei Y, Hughes JWB, Garakani K, Atabai K, Auyeung VC, Papa FR, Chapman HA. BCL-2 Modulates IRE1α Activation to Attenuate Endoplasmic Reticulum Stress and Pulmonary Fibrosis. Am J Respir Cell Mol Biol 2024; 70:247-258. [PMID: 38117250 DOI: 10.1165/rcmb.2023-0109oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 12/19/2023] [Indexed: 12/21/2023] Open
Abstract
BCL-2 family members are known to be implicated in survival in numerous biological settings. Here, we provide evidence that in injury and repair processes in lungs, BCL-2 mainly acts to attenuate endoplasmic reticulum (ER) stress and limit extracellular matrix accumulation. Days after an intratracheal bleomycin challenge, mice lose a fraction of their alveolar type II epithelium from terminal ER stress driven by activation of the critical ER sensor and stress effector IRE1α. This fraction is dramatically increased by BCL-2 inhibition, because IRE1α activation is dependent on its physical association with the BCL-2-proapoptotic family member BAX, and we found BCL-2 to disrupt this association in vitro. In vivo, navitoclax (a BCL-2/BCL-xL inhibitor) given 15-21 days after bleomycin challenge evoked strong activation of IRE-1α in mesenchymal cells and markers of ER stress, but not apoptosis. Remarkably, after BCL-2 inhibition, bleomycin-exposed mice demonstrated persistent collagen accumulation at Day 42, compared with resolution in controls. Enhanced fibrosis proved to be due to the RNAase activity of IRE1α downregulating MRC2 mRNA and protein, a mediator of collagen turnover. The critical role of MRC2 was confirmed in precision-cut lung slice cultures of Day-42 lungs from bleomycin-exposed wild-type and MRC2 null mice. Soluble and tissue collagen accumulated in precision-cut lung slice cultures from navitoclax-treated, bleomycin-challenged mice compared with controls, in a manner nearly identical to that of challenged but untreated MRC2 null mice. Thus, apart from mitochondrial-based antiapoptosis, BCL-2 functions to attenuate ER stress responses, fostering tissue homeostasis and injury repair.
Collapse
Affiliation(s)
- Claude Jourdan Le Saux
- Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine, Department of Medicine, University of California San Francisco, San Francisco, California; and
| | - Tsung Che Ho
- Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine, Department of Medicine, University of California San Francisco, San Francisco, California; and
| | - Alexis M Brumwell
- Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine, Department of Medicine, University of California San Francisco, San Francisco, California; and
| | - Jaymin J Kathiriya
- Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine, Department of Medicine, University of California San Francisco, San Francisco, California; and
| | - Ying Wei
- Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine, Department of Medicine, University of California San Francisco, San Francisco, California; and
| | | | - Kiana Garakani
- Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine, Department of Medicine, University of California San Francisco, San Francisco, California; and
| | - Kamran Atabai
- Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine, Department of Medicine, University of California San Francisco, San Francisco, California; and
| | - Vincent C Auyeung
- Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine, Department of Medicine, University of California San Francisco, San Francisco, California; and
| | - Ferroz R Papa
- Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine, Department of Medicine, University of California San Francisco, San Francisco, California; and
| | - Harold A Chapman
- Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine, Department of Medicine, University of California San Francisco, San Francisco, California; and
| |
Collapse
|
16
|
Neidhardt L, Cloots E, Friemel N, Weiss CAM, Harding HP, McLaughlin SH, Janssens S, Ron D. The IRE1β-mediated unfolded protein response is repressed by the chaperone AGR2 in mucin producing cells. EMBO J 2024; 43:719-753. [PMID: 38177498 PMCID: PMC10907699 DOI: 10.1038/s44318-023-00014-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 01/06/2024] Open
Abstract
Effector mechanisms of the unfolded protein response (UPR) in the endoplasmic reticulum (ER) are well-characterised, but how ER proteostasis is sensed is less well understood. Here, we exploited the beta isoform of the UPR transducer IRE1, that is specific to mucin-producing cells in order to gauge the relative regulatory roles of activating ligands and repressing chaperones of the specialised ER of goblet cells. Replacement of the stress-sensing luminal domain of endogenous IRE1α in CHO cells (normally expressing neither mucin nor IRE1β) with the luminal domain of IRE1β deregulated basal IRE1 activity. The mucin-specific chaperone AGR2 repressed IRE1 activity in cells expressing the domain-swapped IRE1β/α chimera, but had no effect on IRE1α. Introduction of the goblet cell-specific client MUC2 reversed AGR2-mediated repression of the IRE1β/α chimera. In vitro, AGR2 actively de-stabilised the IRE1β luminal domain dimer and formed a reversible complex with the inactive monomer. These features of the IRE1β-AGR2 couple suggest that active repression of IRE1β by a specialised mucin chaperone subordinates IRE1 activity to a proteostatic challenge unique to goblet cells, a challenge that is otherwise poorly recognised by the pervasive UPR transducers.
Collapse
Affiliation(s)
- Lisa Neidhardt
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK.
| | - Eva Cloots
- Laboratory for ER stress and Inflammation, VIB Center for Inflammation Research, Technologiepark-Zwijnaarde 71, 9052, Ghent, Belgium
- Department of Pediatrics and Internal Medicine, Faculty of Medicine and Health Sciences, Ghent University, Technologiepark-Zwijnaarde 71, 9052, Ghent, Belgium
| | - Natalie Friemel
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Caroline A M Weiss
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Heather P Harding
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Stephen H McLaughlin
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Sophie Janssens
- Laboratory for ER stress and Inflammation, VIB Center for Inflammation Research, Technologiepark-Zwijnaarde 71, 9052, Ghent, Belgium
- Department of Pediatrics and Internal Medicine, Faculty of Medicine and Health Sciences, Ghent University, Technologiepark-Zwijnaarde 71, 9052, Ghent, Belgium
| | - David Ron
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK.
| |
Collapse
|
17
|
Xue M, Irshad Z, Rabbani N, Thornalley PJ. Increased cellular protein modification by methylglyoxal activates endoplasmic reticulum-based sensors of the unfolded protein response. Redox Biol 2024; 69:103025. [PMID: 38199038 PMCID: PMC10821617 DOI: 10.1016/j.redox.2024.103025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 12/30/2023] [Accepted: 01/01/2024] [Indexed: 01/12/2024] Open
Abstract
The unfolded protein response (UPR) detects increased misfolded proteins and activates protein refolding, protein degradation and inflammatory responses. UPR sensors in the endoplasmic reticulum, IRE1α and PERK, bind and are activated by proteins with unexpected surface hydrophobicity, whereas sensor ATF6 is activated by proteolytic cleavage when released from complexation with protein disulfide isomerases (PDIs). Metabolic dysfunction leading to the formation of misfolded proteins with surface hydrophobicity and disruption of ATF6-PDI complexes leading to activation of UPR sensors remains unclear. The cellular concentration of reactive dicarbonyl metabolite, methylglyoxal (MG), is increased in impaired metabolic health, producing increased MG-modified cellular proteins. Herein we assessed the effect of high glucose concentration and related increased cellular MG on activation status of IRE1α, PERK and ATF6. Human aortal endothelial cells and HMEC-1 microvascular endothelial cells were incubated in low and high glucose concentration to model blood glucose control, with increase or decrease of MG by silencing or increasing expression of glyoxalase 1 (Glo1), which metabolizes MG. Increased MG induced by high glucose concentration activated IRE1α, PERK and ATF6 and related downstream signalling leading to increased chaperone, apoptotic and inflammatory gene expression. Correction of increased MG by increasing Glo1 expression prevented UPR activation. MG modification of proteins produces surface hydrophobicity through arginine-derived hydroimidazolone MG-H1 formation, with related protein unfolding and preferentially targets PDIs and chaperone pathways for modification. It thereby poses a major challenge to proteostasis and activates UPR sensors. Pharmacological decrease of MG with Glo1 inducer, trans-resveratrol and hesperetin in combination, offers a novel treatment strategy to counter UPR-related cell dysfunction, particularly in hyperglycemia associated with diabetes.
Collapse
Affiliation(s)
- Mingzhan Xue
- Diabetes Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University (HBKU), Qatar Foundation, P.O. Box 34110, Doha, Qatar
| | - Zehra Irshad
- Clinical Sciences Research Laboratories, Warwick Medical School, University of Warwick, University Hospital, Coventry, CV2 2DX, UK
| | - Naila Rabbani
- Department of Basic Medical Science, College of Medicine, QU Health, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Paul J Thornalley
- Diabetes Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University (HBKU), Qatar Foundation, P.O. Box 34110, Doha, Qatar; Clinical Sciences Research Laboratories, Warwick Medical School, University of Warwick, University Hospital, Coventry, CV2 2DX, UK; College of Health and Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, P.O. Box 34110, Doha, Qatar.
| |
Collapse
|
18
|
Ottens F, Efstathiou S, Hoppe T. Cutting through the stress: RNA decay pathways at the endoplasmic reticulum. Trends Cell Biol 2023:S0962-8924(23)00236-2. [PMID: 38008608 DOI: 10.1016/j.tcb.2023.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/28/2023]
Abstract
The endoplasmic reticulum (ER) is central to the processing of luminal, transmembrane, and secretory proteins, and maintaining a functional ER is essential for organismal physiology and health. Increased protein-folding load on the ER causes ER stress, which activates quality control mechanisms to restore ER function and protein homeostasis. Beyond protein quality control, mRNA decay pathways have emerged as potent ER fidelity regulators, but their mechanistic roles in ER quality control and their interrelationships remain incompletely understood. Herein, we review ER-associated RNA decay pathways - including regulated inositol-requiring enzyme 1α (IRE1α)-dependent mRNA decay (RIDD), nonsense-mediated mRNA decay (NMD), and Argonaute-dependent RNA silencing - in ER homeostasis, and highlight the intricate coordination of ER-targeted RNA and protein decay mechanisms and their association with antiviral defense.
Collapse
Affiliation(s)
- Franziska Ottens
- Institute for Genetics, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Sotirios Efstathiou
- Institute for Genetics, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Thorsten Hoppe
- Institute for Genetics, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and University Hospital of Cologne, Cologne, Germany.
| |
Collapse
|
19
|
Kischuck LT, Brown AI. Tube geometry controls protein cluster conformation and stability on the endoplasmic reticulum surface. SOFT MATTER 2023; 19:6771-6783. [PMID: 37642520 DOI: 10.1039/d3sm00694h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
The endoplasmic reticulum (ER), a cellular organelle that forms a cell-spanning network of tubes and sheets, is an important location of protein synthesis and folding. When the ER experiences sustained unfolded protein stress, IRE1 proteins embedded in the ER membrane activate and assemble into clusters as part of the unfolded protein response (UPR). We use kinetic Monte Carlo simulations to explore IRE1 clustering dynamics on the surface of ER tubes. While initially growing clusters are approximately round, once a cluster is sufficiently large a shorter interface length can be achieved by 'wrapping' around the ER tube. A wrapped cluster can grow without further interface length increases. Relative to wide tubes, narrower tubes enable cluster wrapping at smaller cluster sizes. Our simulations show that wrapped clusters on narrower tubes grow more rapidly, evaporate more slowly, and require a lower protein concentration to grow compared to equal-area round clusters on wider tubes. These results suggest that cluster wrapping, facilitated by narrower tubes, could be an important factor in the growth and stability of IRE1 clusters and thus impact the persistence of the UPR, connecting geometry to signaling behavior. This work is consistent with recent experimental observations of IRE1 clusters wrapped around narrow tubes in the ER network.
Collapse
Affiliation(s)
- Liam T Kischuck
- Department of Physics, Toronto Metropolitan University, Toronto, Ontario, M5B 2K3, Canada.
| | - Aidan I Brown
- Department of Physics, Toronto Metropolitan University, Toronto, Ontario, M5B 2K3, Canada.
| |
Collapse
|
20
|
Reinhardt R, Leonard TA. A critical evaluation of protein kinase regulation by activation loop autophosphorylation. eLife 2023; 12:e88210. [PMID: 37470698 PMCID: PMC10359097 DOI: 10.7554/elife.88210] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/07/2023] [Indexed: 07/21/2023] Open
Abstract
Phosphorylation of proteins is a ubiquitous mechanism of regulating their function, localization, or activity. Protein kinases, enzymes that use ATP to phosphorylate protein substrates are, therefore, powerful signal transducers in eukaryotic cells. The mechanism of phosphoryl-transfer is universally conserved among protein kinases, which necessitates the tight regulation of kinase activity for the orchestration of cellular processes with high spatial and temporal fidelity. In response to a stimulus, many kinases enhance their own activity by autophosphorylating a conserved amino acid in their activation loop, but precisely how this reaction is performed is controversial. Classically, kinases that autophosphorylate their activation loop are thought to perform the reaction in trans, mediated by transient dimerization of their kinase domains. However, motivated by the recently discovered regulation mechanism of activation loop cis-autophosphorylation by a kinase that is autoinhibited in trans, we here review the various mechanisms of autoregulation that have been proposed. We provide a framework for critically evaluating biochemical, kinetic, and structural evidence for protein kinase dimerization and autophosphorylation, and share some thoughts on the implications of these mechanisms within physiological signaling networks.
Collapse
Affiliation(s)
- Ronja Reinhardt
- Max Perutz Labs, Vienna Biocenter Campus (VBC)ViennaAustria
- Medical University of Vienna, Center for Medical BiochemistryViennaAustria
| | - Thomas A Leonard
- Max Perutz Labs, Vienna Biocenter Campus (VBC)ViennaAustria
- Medical University of Vienna, Center for Medical BiochemistryViennaAustria
| |
Collapse
|
21
|
Kovaleva V, Yu LY, Ivanova L, Shpironok O, Nam J, Eesmaa A, Kumpula EP, Sakson S, Toots U, Ustav M, Huiskonen JT, Voutilainen MH, Lindholm P, Karelson M, Saarma M. MANF regulates neuronal survival and UPR through its ER-located receptor IRE1α. Cell Rep 2023; 42:112066. [PMID: 36739529 DOI: 10.1016/j.celrep.2023.112066] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/20/2022] [Accepted: 01/19/2023] [Indexed: 02/05/2023] Open
Abstract
Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an endoplasmic reticulum (ER)-located protein with cytoprotective effects in neurons and pancreatic β cells in vitro and in models of neurodegeneration and diabetes in vivo. However, the exact mode of MANF action has remained elusive. Here, we show that MANF directly interacts with the ER transmembrane unfolded protein response (UPR) sensor IRE1α, and we identify the binding interface between MANF and IRE1α. The expression of wild-type MANF, but not its IRE1α binding-deficient mutant, attenuates UPR signaling by decreasing IRE1α oligomerization; phosphorylation; splicing of Xbp1, Atf6, and Txnip levels; and protecting neurons from ER stress-induced death. MANF-IRE1α interaction and not MANF-BiP interaction is crucial for MANF pro-survival activity in neurons in vitro and is required to protect dopamine neurons in an animal model of Parkinson's disease. Our data show IRE1α as an intracellular receptor for MANF and regulator of neuronal survival.
Collapse
Affiliation(s)
- Vera Kovaleva
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland.
| | - Li-Ying Yu
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | - Larisa Ivanova
- Institute of Chemistry, University of Tartu, 50411 Tartu, Estonia
| | - Olesya Shpironok
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | - Jinhan Nam
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland; Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, 00014 Helsinki, Finland
| | - Ave Eesmaa
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | - Esa-Pekka Kumpula
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | - Sven Sakson
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | | | | | - Juha T Huiskonen
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | - Merja H Voutilainen
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland; Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, 00014 Helsinki, Finland
| | - Päivi Lindholm
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | - Mati Karelson
- Institute of Chemistry, University of Tartu, 50411 Tartu, Estonia
| | - Mart Saarma
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland.
| |
Collapse
|
22
|
Chaperone-Dependent Mechanisms as a Pharmacological Target for Neuroprotection. Int J Mol Sci 2023; 24:ijms24010823. [PMID: 36614266 PMCID: PMC9820882 DOI: 10.3390/ijms24010823] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 01/05/2023] Open
Abstract
Modern pharmacotherapy of neurodegenerative diseases is predominantly symptomatic and does not allow vicious circles causing disease development to break. Protein misfolding is considered the most important pathogenetic factor of neurodegenerative diseases. Physiological mechanisms related to the function of chaperones, which contribute to the restoration of native conformation of functionally important proteins, evolved evolutionarily. These mechanisms can be considered promising for pharmacological regulation. Therefore, the aim of this review was to analyze the mechanisms of endoplasmic reticulum stress (ER stress) and unfolded protein response (UPR) in the pathogenesis of neurodegenerative diseases. Data on BiP and Sigma1R chaperones in clinical and experimental studies of Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and Huntington's disease are presented. The possibility of neuroprotective effect dependent on Sigma1R ligand activation in these diseases is also demonstrated. The interaction between Sigma1R and BiP-associated signaling in the neuroprotection is discussed. The performed analysis suggests the feasibility of pharmacological regulation of chaperone function, possibility of ligand activation of Sigma1R in order to achieve a neuroprotective effect, and the need for further studies of the conjugation of cellular mechanisms controlled by Sigma1R and BiP chaperones.
Collapse
|
23
|
Porter AW, Brodsky JL, Buck TM. Emerging links between endoplasmic reticulum stress responses and acute kidney injury. Am J Physiol Cell Physiol 2022; 323:C1697-C1703. [PMID: 36280391 PMCID: PMC9722262 DOI: 10.1152/ajpcell.00370.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/12/2022] [Accepted: 10/12/2022] [Indexed: 01/26/2023]
Abstract
All cell types must maintain homeostasis under periods of stress. To prevent the catastrophic effects of stress, all cell types also respond to stress by inducing protective pathways. Within the cell, the endoplasmic reticulum (ER) is exquisitely stress-sensitive, primarily because this organelle folds, posttranslationally processes, and sorts one-third of the proteome. In the 1990s, a specialized ER stress response pathway was discovered, the unfolded protein response (UPR), which specifically protects the ER from damaged proteins and toxic chemicals. Not surprisingly, UPR-dependent responses are essential to maintain the function and viability of cells continuously exposed to stress, such as those in the kidney, which have high metabolic demands, produce myriad protein assemblies, continuously filter toxins, and synthesize ammonia. In this mini-review, we highlight recent articles that link ER stress and the UPR with acute kidney injury (AKI), a disease that arises in ∼10% of all hospitalized individuals and nearly half of all people admitted to intensive care units. We conclude with a discussion of prospects for treating AKI with emerging drugs that improve ER function.
Collapse
Affiliation(s)
- Aidan W Porter
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Pediatrics, Nephrology Division, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Teresa M Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
| |
Collapse
|