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Xie Z, Zhao S, Tu Y, Liu E, Li Y, Wang X, Chen C, Zhai S, Qi J, Wu C, Wu H, Zhou M, Wang W. Proteasome resides in and dismantles plant heat stress granules constitutively. Mol Cell 2024; 84:3320-3335.e7. [PMID: 39173636 DOI: 10.1016/j.molcel.2024.07.033] [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: 08/11/2023] [Revised: 05/30/2024] [Accepted: 07/31/2024] [Indexed: 08/24/2024]
Abstract
Stress granules (SGs) are conserved reversible cytoplasmic condensates enriched with aggregation-prone proteins assembled in response to various stresses. How plants regulate SG dynamics is unclear. Here, we show that 26S proteasome is a stable component of SGs, promoting the overall clearance of SGs without affecting the molecular mobility of SG components. Increase in either temperature or duration of heat stress reduces the molecular mobility of SG marker proteins and suppresses SG clearance. Heat stress induces dramatic ubiquitylation of SG components and enhances the activities of SG-resident proteasomes, allowing the degradation of SG components even during the assembly phase. Their proteolytic activities enable the timely disassembly of SGs and secure the survival of plant cells during the recovery from heat stress. Therefore, our findings identify the cellular process that de-couples macroscopic dynamics of SGs from the molecular dynamics of its constituents and highlights the significance of the proteasomes in SG disassembly.
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Affiliation(s)
- Zhouli Xie
- State Key Laboratory for Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China; Center for Life Sciences, Beijing 100871, China; Hubei Hongshan Laboratory, Wuhan 430070, China; National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, The Center of Crop Nanobiotechnology, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Shuai Zhao
- State Key Laboratory for Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China; Center for Life Sciences, Beijing 100871, China
| | - Yuchen Tu
- State Key Laboratory for Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Enhui Liu
- College of Life Sciences, Capital Normal University, Beijing 100048, China; Beijing Key Laboratory of Plant Gene Resources and Biotechnology for Carbon Reduction and Environmental Improvement, Beijing 100048, China
| | - Ying Li
- State Key Laboratory for Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China; Center for Life Sciences, Beijing 100871, China
| | - Xingwei Wang
- State Key Laboratory for Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Changtian Chen
- State Key Laboratory for Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China; Center for Life Sciences, Beijing 100871, China
| | - Shuwei Zhai
- Hubei Hongshan Laboratory, Wuhan 430070, China; National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, The Center of Crop Nanobiotechnology, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jie Qi
- Hubei Hongshan Laboratory, Wuhan 430070, China; National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, The Center of Crop Nanobiotechnology, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Chengyun Wu
- The National Engineering Lab of Crop Stress Resistance Breeding, School of Life Sciences, Anhui Agricultural University, Hefei 230036, China
| | - Honghong Wu
- Hubei Hongshan Laboratory, Wuhan 430070, China; National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, The Center of Crop Nanobiotechnology, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Mian Zhou
- College of Life Sciences, Capital Normal University, Beijing 100048, China; Beijing Key Laboratory of Plant Gene Resources and Biotechnology for Carbon Reduction and Environmental Improvement, Beijing 100048, China
| | - Wei Wang
- State Key Laboratory for Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China; Center for Life Sciences, Beijing 100871, China.
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Abstract
The proteasome degrades most cellular proteins in a controlled and tightly regulated manner and thereby controls many processes, including cell cycle, transcription, signalling, trafficking and protein quality control. Proteasomal degradation is vital in all cells and organisms, and dysfunction or failure of proteasomal degradation is associated with diverse human diseases, including cancer and neurodegeneration. Target selection is an important and well-established way to control protein degradation. In addition, mounting evidence indicates that cells adjust proteasome-mediated degradation to their needs by regulating proteasome abundance through the coordinated expression of proteasome subunits and assembly chaperones. Central to the regulation of proteasome assembly is TOR complex 1 (TORC1), which is the master regulator of cell growth and stress. This Review discusses how proteasome assembly and the regulation of proteasomal degradation are integrated with cellular physiology, including the interplay between the proteasome and autophagy pathways. Understanding these mechanisms has potential implications for disease therapy, as the misregulation of proteasome function contributes to human diseases such as cancer and neurodegeneration.
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Abu-El-Rub E, Sequiera GL, Sareen N, Yan W, Moudgil M, Sabbir MG, Dhingra S. Hypoxia-induced 26S proteasome dysfunction increases immunogenicity of mesenchymal stem cells. Cell Death Dis 2019; 10:90. [PMID: 30692516 PMCID: PMC6349874 DOI: 10.1038/s41419-019-1359-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 01/04/2019] [Accepted: 01/11/2019] [Indexed: 02/07/2023]
Abstract
Bone marrow-derived allogeneic (donor derived) mesenchymal stem cells (MSCs) are immunoprivileged and are considered to be prominent candidates for regenerative therapy for numerous degenerative diseases. Even though the outcome of initial allogeneic MSCs based clinical trials was encouraging, the overall enthusiasm, of late, has dimmed down. This is due to failure of long-term survival of transplanted cells in the recipient. In fact, recent analyses of allogeneic MSC-based studies demonstrated that cells after transplantation turned immunogenic and were subsequently rejected by host immune system. The current study reveals a novel mechanism of immune switch in MSCs. We demonstrate that hypoxia, a common denominator of ischemic tissues, induces an immune shift in MSCs from immunoprivileged to immunogenic state. The immunoprivilege of MSCs is preserved by downregulation or the absence of major histocompatibility complex class II (MHC-II) molecules. We found that 26S proteasome-mediated intracellular degradation of MHC-II helps maintain the absence of MHC-II expression on cell surface in normoxic MSCs and preserves their immunoprivilege. The exposure to hypoxia leads to dissociation of 19S and 20S subunits, and inactivation of 26S proteasome. This prevented the degradation of MHC-II and, as a result, the MSCs became immunogenic. Furthermore, we found that hypoxia-induced decrease in the levels of a chaperon protein HSP90α is responsible for inactivation of 26S proteasome. Maintaining HSP90α levels in hypoxic MSCs preserved the immunoprivilege of MSCs. Therefore, hypoxia-induced inactivation of 26S proteasome assembly instigates loss of immunoprivilege of allogeneic mesenchymal stem cells. Maintaining 26S proteasome activity in mesenchymal stem cells preserves their immunoprivilege.
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Affiliation(s)
- Ejlal Abu-El-Rub
- Regenerative Medicine Program, Institute of Cardiovascular Sciences, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada.,St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | - Glen Lester Sequiera
- Regenerative Medicine Program, Institute of Cardiovascular Sciences, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada.,St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | - Niketa Sareen
- Regenerative Medicine Program, Institute of Cardiovascular Sciences, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada.,St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | - Weiang Yan
- Regenerative Medicine Program, Institute of Cardiovascular Sciences, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada.,St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | - Meenal Moudgil
- Regenerative Medicine Program, Institute of Cardiovascular Sciences, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada.,St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | - Mohammad Golam Sabbir
- St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada.,Division of Neurodegenerative Disorders, University of Manitoba, Winnipeg, MB, Canada
| | - Sanjiv Dhingra
- Regenerative Medicine Program, Institute of Cardiovascular Sciences, Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada. .,St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada.
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