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Kucińska MK, Molinari M. Control of nuclear envelope dynamics during acute ER stress by LINC complexes disassembly and selective, asymmetric autophagy of the outer nuclear membrane. Autophagy 2023:1-3. [PMID: 38153175 DOI: 10.1080/15548627.2023.2299123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/15/2023] [Indexed: 12/29/2023] Open
Abstract
The endoplasmic reticulum (ER) extends to the outer (ONM) and the inner (INM) nuclear membrane forming the nuclear envelope (NE) that delimits the nucleoplasm containing the cell genome. Unfolded protein responses (UPRs) and reticulophagy responses increase or reduce ER size and activities, respectively. If dynamic changes of the ER are transmitted to the contiguous NE was not known. In our recent publication, we report on the transmission of stress-induced ER expansion to the NE, which requires disassembly of the Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes deputed to ensure a physical connection between the cytoplasmic cytoskeleton and the nuclear lamina and to maintain the width between INM and ONM within 50 nm. LINC complexes disassembly relies on reduction of the disulfide bond that covalently links SUN proteins in the INM and KASH proteins (SYNE/NESPRIN proteins in mammals) in the ONM by the ONM-resident reductase TMX4. Upon stress resolution, the physiological shape of the NE is reestablished by SEC62-driven ONM-phagy, where ONM-derived vesicles are directly captured by RAB7- and LAMP1-positive endolysosomes in processes that proceed via asymmetric microautophagy of the NE.
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Affiliation(s)
- Marika K Kucińska
- Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Bellinzona, Switzerland
- Department of Biology, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Maurizio Molinari
- Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Bellinzona, Switzerland
- School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Cain NE, Jahed Z, Schoenhofen A, Valdez VA, Elkin B, Hao H, Harris NJ, Herrera LA, Woolums BM, Mofrad MRK, Luxton GWG, Starr DA. Conserved SUN-KASH Interfaces Mediate LINC Complex-Dependent Nuclear Movement and Positioning. Curr Biol 2018; 28:3086-3097.e4. [PMID: 30245107 DOI: 10.1016/j.cub.2018.08.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 06/18/2018] [Accepted: 08/01/2018] [Indexed: 12/20/2022]
Abstract
Many nuclear positioning events involve linker of nucleoskeleton and cytoskeleton (LINC) complexes, which transmit forces generated by the cytoskeleton across the nuclear envelope. LINC complexes are formed by trans-luminal interactions between inner nuclear membrane SUN proteins and outer nuclear membrane KASH proteins, but how these interactions are regulated is poorly understood. We combine in vivo C. elegans genetics, in vitro wounded fibroblast polarization, and in silico molecular dynamics simulations to elucidate mechanisms of LINC complexes. The extension of the KASH domain by a single alanine residue or the mutation of the conserved tyrosine at -7 completely blocked the nuclear migration function of C. elegans UNC-83. Analogous mutations at -7 of mouse nesprin-2 disrupted rearward nuclear movements in NIH 3T3 cells, but did not disrupt ANC-1 in nuclear anchorage. Furthermore, conserved cysteines predicted to form a disulfide bond between SUN and KASH proteins are important for the function of certain LINC complexes, and might promote a developmental switch between nuclear migration and nuclear anchorage. Mutations of conserved cysteines in SUN or KASH disrupted ANC-1-dependent nuclear anchorage in C. elegans and Nesprin-2G-dependent nuclear movements in polarizing fibroblasts. However, the SUN cysteine mutation did not disrupt nuclear migration. Moreover, molecular dynamics simulations showed that a disulfide bond is necessary for the maximal transmission of cytoskeleton-generated forces by LINC complexes in silico. Thus, we have demonstrated functions for SUN-KASH binding interfaces, including a predicted intermolecular disulfide bond, as mechanistic determinants of nuclear positioning that may represent targets for regulation.
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Affiliation(s)
- Natalie E Cain
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Zeinab Jahed
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, 208A Stanley Hall, Berkeley, CA 94720, USA
| | - Amy Schoenhofen
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Venecia A Valdez
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Baila Elkin
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Hongyan Hao
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Nathan J Harris
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Leslie A Herrera
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Brian M Woolums
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, 208A Stanley Hall, Berkeley, CA 94720, USA
| | - G W Gant Luxton
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Daniel A Starr
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA.
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Zeng X, Li K, Yuan R, Gao H, Luo J, Liu F, Wu Y, Wu G, Yan X. Nuclear Envelope-Associated Chromosome Dynamics during Meiotic Prophase I. Front Cell Dev Biol 2018; 5:121. [PMID: 29376050 PMCID: PMC5767173 DOI: 10.3389/fcell.2017.00121] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/21/2017] [Indexed: 12/21/2022] Open
Abstract
Chromosome dynamics during meiotic prophase I are associated with a series of major events such as chromosomal reorganization and condensation, pairing/synapsis and recombination of the homologs, and chromosome movements at the nuclear envelope (NE). The NE is the barrier separating the nucleus from the cytoplasm and thus plays a central role in NE-associated chromosomal movements during meiosis. Previous studies have shown in various species that NE-linked chromosome dynamics are actually driven by the cytoskeleton. The linker of nucleoskeleton and cytoskeleton (LINC) complexes are important constituents of the NE that facilitate in the transfer of cytoskeletal forces across the NE to individual chromosomes. The LINCs consist of the inner and outer NE proteins Sad1/UNC-84 (SUN), and Klarsicht/Anc-1/Syne (KASH) domain proteins. Meiosis-specific adaptations of the LINC components and unique modifications of the NE are required during chromosomal movements. Nonetheless, the actual role of the NE in chromosomic dynamic movements in plants remains elusive. This review summarizes the findings of recent studies on meiosis-specific constituents and modifications of the NE and corresponding nucleoplasmic/cytoplasmic adaptors being involved in NE-associated movement of meiotic chromosomes, as well as describes the potential molecular network of transferring cytoplasm-derived forces into meiotic chromosomes in model organisms. It helps to gain a better understanding of the NE-associated meiotic chromosomal movements in plants.
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Affiliation(s)
- Xinhua Zeng
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Keqi Li
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Rong Yuan
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Hongfei Gao
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Junling Luo
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Fang Liu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Yuhua Wu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Gang Wu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Xiaohong Yan
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
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Abstract
Striated muscles contain a tightly ordered cytoplasm in which the shape and size of the nuclei are comparable and nuclear distribution is uniform. These features were recently shown to be essential for muscle function. In an attempt to elucidate mechanisms regulating the position and shape of myonuclei, we analyzed the function of the two KASH proteins that are uniquely present in the Drosophila genome, MSP‑300 and Klarsicht, both expressed in striated muscles. We demonstrated that both KASH proteins cooperate to construct a unique ring composed of MSP‑300 protein that surrounds and attached to the nuclear envelope. The MSP‑300 nuclear ring structure recruits and associates with a network of polarized astral microtubules that enables the dynamic movement and uniform spacing between the nuclei in each muscle fiber.
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Affiliation(s)
- Talila Volk
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
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