1
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Zhang H, Zhang D, Li L, Willard B, Runge KW. In Vivo Proximity Labeling Identifies a New Function for the Lifespan and Autophagy-regulating Kinase Pef1, an Ortholog of Human Cdk5. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.12.598664. [PMID: 38915521 PMCID: PMC11195251 DOI: 10.1101/2024.06.12.598664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Cdk5 is a highly-conserved, noncanonical cell division kinase important to the terminal differentiation of mammalian cells in multiple organ systems. We previously identified Pef1, the Schizosaccharomyces pombe ortholog of cdk5, as regulator of chronological lifespan. To reveal the processes impacted by Pef1, we developed APEX2-biotin phenol-mediated proximity labeling in S. pombe. Efficient labeling required a short period of cell wall digestion and eliminating glucose and nitrogen sources from the medium. We identified 255 high-confidence Pef1 neighbors in growing cells and a novel Pef1-interacting partner, the DNA damage response protein Rad24. The Pef1-Rad24 interaction was validated by reciprocal proximity labeling and co-immunoprecipitation. Eliminating Pef1 partially rescued the DNA damage sensitivity of cells lacking Rad24. To monitor how Pef1 neighbors change under different conditions, cells induced for autophagy were labeled and 177 high-confidence Pef1 neighbors were identified. Gene ontology (GO) analysis of the Pef1 neighbors identified proteins participating in processes required for autophagosome expansion including regulation of actin dynamics and vesicle-mediated transport. Some of these proteins were identified in both exponentially growing and autophagic cells. Pef1-APEX2 proximity labeling therefore identified a new Pef1 function in modulating the DNA damage response and candidate processes that Pef1 and other cdk5 orthologs may regulate.
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Affiliation(s)
- Haitao Zhang
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine at CWRU
| | - Dongmei Zhang
- Lerner Research Institute Proteomics Core and Case Comprehensive Cancer Center Cleveland Clinic Lerner College of Medicine at CWRU
| | - Ling Li
- Lerner Research Institute Proteomics Core and Case Comprehensive Cancer Center Cleveland Clinic Lerner College of Medicine at CWRU
| | - Belinda Willard
- Lerner Research Institute Proteomics Core and Case Comprehensive Cancer Center Cleveland Clinic Lerner College of Medicine at CWRU
| | - Kurt W. Runge
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine at CWRU
- Department of Genomics and Genome Sciences, Case Western Reserve University School of Medicine
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2
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Homa KE, Hocky GM, Suarez C, Kovar DR. Arp2/3 complex- and formin-mediated actin cytoskeleton networks facilitate actin binding protein sorting in fission yeast. Eur J Cell Biol 2024; 103:151404. [PMID: 38493594 PMCID: PMC11211059 DOI: 10.1016/j.ejcb.2024.151404] [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: 11/07/2023] [Revised: 03/01/2024] [Accepted: 03/13/2024] [Indexed: 03/19/2024] Open
Abstract
While it is well-established that F-actin networks with specific organizations and dynamics are tightly regulated by distinct sets of associated actin-binding proteins (ABPs), how ABPs self-sort to particular F-actin networks remains largely unclear. We report that actin assembly factors Arp2/3 complex and formin Cdc12 tune the association of ABPs fimbrin Fim1 and tropomyosin Cdc8 to different F-actin networks in fission yeast. Genetic and pharmacological disruption of F-actin networks revealed that Fim1 is preferentially directed to Arp2/3-complex mediated actin patches, whereas Cdc8 is preferentially targeted to formin Cdc12-mediated filaments in the contractile ring. To investigate the role of Arp2/3 complex- and formin Cdc12-mediated actin assembly, we used four-color TIRF microscopy to observe the in vitro reconstitution of ABP sorting with purified proteins. Fim1 or Cdc8 alone bind similarly well to filaments assembled by either assembly factor. However, in 'competition' reactions containing both actin assembly factors and both ABPs, ∼2.0-fold more Fim1 and ∼3.5-fold more Cdc8 accumulates on Arp2/3 complex branch points and formin Cdc12-assembled actin filaments, respectively. These findings indicate that F-actin assembly factors Arp2/3 complex and formin Cdc12 help facilitate the recruitment of specific ABPs, thereby tuning ABP sorting and subsequently establishing the identity of F-actin networks in fission yeast.
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Affiliation(s)
- Kaitlin E Homa
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, United States
| | - Glen M Hocky
- Department of Chemistry, New York University, New York, NY, United States
| | - Cristian Suarez
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, United States
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, United States; Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, United States.
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3
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Sakamoto R, Murrell MP. F-actin architecture determines the conversion of chemical energy into mechanical work. Nat Commun 2024; 15:3444. [PMID: 38658549 PMCID: PMC11043346 DOI: 10.1038/s41467-024-47593-x] [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: 10/13/2023] [Accepted: 04/03/2024] [Indexed: 04/26/2024] Open
Abstract
Mechanical work serves as the foundation for dynamic cellular processes, ranging from cell division to migration. A fundamental driver of cellular mechanical work is the actin cytoskeleton, composed of filamentous actin (F-actin) and myosin motors, where force generation relies on adenosine triphosphate (ATP) hydrolysis. F-actin architectures, whether bundled by crosslinkers or branched via nucleators, have emerged as pivotal regulators of myosin II force generation. However, it remains unclear how distinct F-actin architectures impact the conversion of chemical energy to mechanical work. Here, we employ in vitro reconstitution of distinct F-actin architectures with purified components to investigate their influence on myosin ATP hydrolysis (consumption). We find that F-actin bundles composed of mixed polarity F-actin hinder network contraction compared to non-crosslinked network and dramatically decelerate ATP consumption rates. Conversely, linear-nucleated networks allow network contraction despite reducing ATP consumption rates. Surprisingly, branched-nucleated networks facilitate high ATP consumption without significant network contraction, suggesting that the branched network dissipates energy without performing work. This study establishes a link between F-actin architecture and myosin energy consumption, elucidating the energetic principles underlying F-actin structure formation and the performance of mechanical work.
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Affiliation(s)
- Ryota Sakamoto
- Department of Biomedical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT, USA
- Systems Biology Institute, 850 West Campus Drive, West Haven, CT, USA
| | - Michael P Murrell
- Department of Biomedical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT, USA.
- Systems Biology Institute, 850 West Campus Drive, West Haven, CT, USA.
- Department of Physics, Yale University, 217 Prospect Street, New Haven, CT, USA.
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4
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Li YB, Shen N, Deng X, Liu Z, Zhu S, Liu C, Tang D, Han LB. Fimbrin associated with Pmk1 to regulate the actin assembly during Magnaporthe oryzae hyphal growth and infection. STRESS BIOLOGY 2024; 4:5. [PMID: 38252344 PMCID: PMC10803693 DOI: 10.1007/s44154-023-00147-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 12/26/2023] [Indexed: 01/23/2024]
Abstract
The dynamic assembly of the actin cytoskeleton is vital for Magnaporthe oryzae development and host infection. The actin-related protein MoFim1 is a key factor for organizing the M. oryzae actin cytoskeleton. Currently, how MoFim1 is regulated in M. oryzae to precisely rearrange the actin cytoskeleton is unclear. In this study, we found that MoFim1 associates with the M. oryzae mitogen-activated protein (MAP) kinase Pmk1 to regulate actin assembly. MoFim1 directly interacted with Pmk1, and the phosphorylation level of MoFim1 was decreased in Δpmk1, which led to a change in the subcellular distribution of MoFim1 in the hyphae of Δpmk1. Moreover, the actin cytoskeleton was aberrantly organized at the hyphal tip in the Δpmk1, which was similar to what was observed in the Δmofim1 during hyphal growth. Furthermore, phosphorylation analysis revealed that Pmk1 could phosphorylate MoFim1 at serine 94. Loss of phosphorylation of MoFim1 at serine 94 decreased actin bundling activity. Additionally, the expression of the site mutant of MoFim1 S94D (in which serine 94 was replaced with aspartate to mimic phosphorylation) in Δpmk1 could reverse the defects in actin organization and hyphal growth in Δpmk1. It also partially rescues the formation of appressorium failure in Δpmk1. Taken together, these findings suggest a regulatory mechanism in which Pmk1 phosphorylates MoFim1 to regulate the assembly of the actin cytoskeleton during hyphal development and pathogenesis.
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Affiliation(s)
- Yuan-Bao Li
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Ningning Shen
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Xianya Deng
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- School of Future Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Zixuan Liu
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- School of Future Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Shuai Zhu
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Chengyu Liu
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Dingzhong Tang
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
- College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
| | - Li-Bo Han
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
- College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
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5
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Ishida H, Woodman AG, Kitada N, Aizawa T, Vogel HJ. The Dictyostelium discoideum FimA protein, unlike yeast and plant fimbrins, is regulated by calcium similar to mammalian plastins. Sci Rep 2023; 13:16208. [PMID: 37758724 PMCID: PMC10533516 DOI: 10.1038/s41598-023-42682-1] [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: 06/21/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
Plastins, also known as fimbrins, are highly conserved eukaryotic multidomain proteins that are involved in actin-bundling. They all contain four independently folded Calponin Homology-domains and an N-terminal headpiece that is comprised of two calcium-binding EF-hand motifs. Since calcium-binding has been shown to be integral to regulating the activity of the three mammalian plastin proteins, we decided to study the properties of the headpiece regions of fimbrins from the model plant Arabidopsis thaliana, the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe and the amoeba Dictyostelium discoideum. Of these protein domains only the FimA headpiece from the amoeba protein possesses calcium binding properties. Structural characterization of this protein domain by multidimensional NMR and site-directed mutagenesis studies indicates that this EF-hand region of FimA also contains a regulatory 'switch helix' that is essential to regulating the activity of the human L-plastin protein. Interestingly this regulatory helical region seems to be lacking in the plant and yeast proteins and in fimbrins from all other nonmotile systems. Typical calmodulin antagonists can displace the switch-helix from the FimA headpiece, suggesting that such drugs can deregulate the Ca2+-regulation of the actin-bunding in the amoeba, thereby making it a useful organism for drug screening against mammalian plastins.
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Affiliation(s)
- Hiroaki Ishida
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Andrew G Woodman
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Naoya Kitada
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Tomoyasu Aizawa
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Hans J Vogel
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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6
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Zhong W, Pathak JL, Liang Y, Zhytnik L, Pals G, Eekhoff EMW, Bravenboer N, Micha D. The intricate mechanism of PLS3 in bone homeostasis and disease. Front Endocrinol (Lausanne) 2023; 14:1168306. [PMID: 37484945 PMCID: PMC10361617 DOI: 10.3389/fendo.2023.1168306] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 06/19/2023] [Indexed: 07/25/2023] Open
Abstract
Since our discovery in 2013 that genetic defects in PLS3 lead to bone fragility, the mechanistic details of this process have remained obscure. It has been established that PLS3 variants cause syndromic and nonsyndromic osteoporosis as well as osteoarthritis. PLS3 codes for an actin-bundling protein with a broad pattern of expression. As such, it is puzzling how PLS3 specifically leads to bone-related disease presentation. Our review aims to summarize the current state of knowledge regarding the function of PLS3 in the predominant cell types in the bone tissue, the osteocytes, osteoblasts and osteoclasts. This is related to the role of PLS3 in regulating mechanotransduction, calcium regulation, vesicle trafficking, cell differentiation and mineralization as part of the complex bone pathology presented by PLS3 defects. Considering the consequences of PLS3 defects on multiple aspects of bone tissue metabolism, our review motivates the study of its mechanism in bone diseases which can potentially help in the design of suitable therapy.
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Affiliation(s)
- Wenchao Zhong
- Department of Human Genetics, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Department of Clinical Chemistry, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Amsterdam Movement Sciences, Tissue Function And Regeneration, Amsterdam, Netherlands
- Department of Temporomandibular Joint, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Janak L. Pathak
- Department of Temporomandibular Joint, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Yueting Liang
- Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing, China
- The Second Clinical College, Guangzhou Medical University, Guangzhou, China
| | - Lidiia Zhytnik
- Department of Human Genetics, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Amsterdam Movement Sciences, Tissue Function And Regeneration, Amsterdam, Netherlands
- Department of Traumatology and Orthopaedics, Institute of Clinical Medicine, The University of Tartu, Tartu, Estonia
| | - Gerard Pals
- Department of Human Genetics, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Amsterdam Movement Sciences, Tissue Function And Regeneration, Amsterdam, Netherlands
| | - Elisabeth M. W. Eekhoff
- Department Internal Medicine Section Endocrinology and Metabolism, Amsterdam UMC Location Vrije Universiteit Amsterdam, Rare Bone Disease Center, AMS, Amsterdam, Netherlands
- Amsterdam Reproduction and Development Research Institute, Amsterdam, Netherlands
| | - Nathalie Bravenboer
- Department of Clinical Chemistry, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Amsterdam Movement Sciences, Tissue Function And Regeneration, Amsterdam, Netherlands
| | - Dimitra Micha
- Department of Human Genetics, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Amsterdam Movement Sciences, Tissue Function And Regeneration, Amsterdam, Netherlands
- Amsterdam Reproduction and Development Research Institute, Amsterdam, Netherlands
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7
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Han X, Hu Z, Surya W, Ma Q, Zhou F, Nordenskiöld L, Torres J, Lu L, Miao Y. The intrinsically disordered region of coronins fine-tunes oligomerization and actin polymerization. Cell Rep 2023; 42:112594. [PMID: 37269287 DOI: 10.1016/j.celrep.2023.112594] [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: 10/18/2022] [Revised: 04/21/2023] [Accepted: 05/16/2023] [Indexed: 06/05/2023] Open
Abstract
Coronins play critical roles in actin network formation. The diverse functions of coronins are regulated by the structured N-terminal β propeller and the C-terminal coiled coil (CC). However, less is known about a middle "unique region" (UR), which is an intrinsically disordered region (IDR). The UR/IDR is an evolutionarily conserved signature in the coronin family. By integrating biochemical and cell biology experiments, coarse-grained simulations, and protein engineering, we find that the IDR optimizes the biochemical activities of coronins in vivo and in vitro. The budding yeast coronin IDR plays essential roles in regulating Crn1 activity by fine-tuning CC oligomerization and maintaining Crn1 as a tetramer. The IDR-guided optimization of Crn1 oligomerization is critical for F-actin cross-linking and regulation of Arp2/3-mediated actin polymerization. The final oligomerization status and homogeneity of Crn1 are contributed by three examined factors: helix packing, the energy landscape of the CC, and the length and molecular grammar of the IDR.
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Affiliation(s)
- Xiao Han
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Zixin Hu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Wahyu Surya
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Qianqian Ma
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Feng Zhou
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Lars Nordenskiöld
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Jaume Torres
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Lanyuan Lu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; Institute for Digital Molecular Analytics and Science, Nanyang Technological University, Singapore 636921, Singapore.
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8
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Stam S, Gardel ML, Weirich KL. Direct detection of deformation modes on varying length scales in active biopolymer networks. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.15.540780. [PMID: 37292666 PMCID: PMC10245561 DOI: 10.1101/2023.05.15.540780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Correlated flows and forces that emerge from active matter orchestrate complex processes such as shape regulation and deformations in biological cells and tissues. The active materials central to cellular mechanics are cytoskeletal networks, where molecular motor activity drives deformations and remodeling. Here, we investigate deformation modes in actin networks driven by the molecular motor myosin II through quantitative fluorescence microscopy. We examine the deformation anisotropy at different length scales in networks of entangled, cross-linked, and bundled actin. In sparsely cross-linked networks, we find myosin-dependent biaxial buckling modes across length scales. In cross-linked bundled networks, uniaxial contraction is predominate on long length scales, while the uniaxial or biaxial nature of the deformation depends on bundle microstructure at shorter length scales. The anisotropy of deformations may provide insight to regulation of collective behavior in a variety of active materials.
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Affiliation(s)
- Samantha Stam
- Biophysical Sciences Graduate Program, University of Chicago, Chicago, IL 60637
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637
- Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112
- Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112
| | - Margaret L Gardel
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637
- James Franck Institute, University of Chicago, Chicago, IL 60637
- Department of Physics, University of Chicago, Chicago, IL 60637
| | - Kimberly L Weirich
- James Franck Institute, University of Chicago, Chicago, IL 60637
- Department of Materials Science & Engineering, Clemson University, Clemson, SC 29634
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9
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Hennlein L, Ghanawi H, Gerstner F, Palominos García E, Yildirim E, Saal-Bauernschubert L, Moradi M, Deng C, Klein T, Appenzeller S, Sauer M, Briese M, Simon C, Sendtner M, Jablonka S. Plastin 3 rescues cell surface translocation and activation of TrkB in spinal muscular atrophy. J Cell Biol 2023; 222:e202204113. [PMID: 36607273 PMCID: PMC9827530 DOI: 10.1083/jcb.202204113] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 10/12/2022] [Accepted: 12/08/2022] [Indexed: 01/07/2023] Open
Abstract
Plastin 3 (PLS3) is an F-actin-bundling protein that has gained attention as a modifier of spinal muscular atrophy (SMA) pathology. SMA is a lethal pediatric neuromuscular disease caused by loss of or mutations in the Survival Motor Neuron 1 (SMN1) gene. Pathophysiological hallmarks are cellular maturation defects of motoneurons prior to degeneration. Despite the observed beneficial modifying effect of PLS3, the mechanism of how it supports F-actin-mediated cellular processes in motoneurons is not yet well understood. Our data reveal disturbed F-actin-dependent translocation of the Tropomyosin receptor kinase B (TrkB) to the cell surface of Smn-deficient motor axon terminals, resulting in reduced TrkB activation by its ligand brain-derived neurotrophic factor (BDNF). Improved actin dynamics by overexpression of hPLS3 restores membrane recruitment and activation of TrkB and enhances spontaneous calcium transients by increasing Cav2.1/2 "cluster-like" formations in SMA axon terminals. Thus, our study provides a novel role for PLS3 in supporting correct alignment of transmembrane proteins, a key mechanism for (moto)-neuronal development.
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Affiliation(s)
- Luisa Hennlein
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Hanaa Ghanawi
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Florian Gerstner
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig, Germany
| | | | - Ezgi Yildirim
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | | | - Mehri Moradi
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Chunchu Deng
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Teresa Klein
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Silke Appenzeller
- Comprehensive Cancer Center Mainfranken; Core Unit Bioinformatics, University Hospital Würzburg, Würzburg, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Michael Briese
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Christian Simon
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig, Germany
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Sibylle Jablonka
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
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10
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Rajan S, Kudryashov DS, Reisler E. Actin Bundles Dynamics and Architecture. Biomolecules 2023; 13:450. [PMID: 36979385 PMCID: PMC10046292 DOI: 10.3390/biom13030450] [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: 12/24/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/04/2023] Open
Abstract
Cells use the actin cytoskeleton for many of their functions, including their division, adhesion, mechanosensing, endo- and phagocytosis, migration, and invasion. Actin bundles are the main constituent of actin-rich structures involved in these processes. An ever-increasing number of proteins that crosslink actin into bundles or regulate their morphology is being identified in cells. With recent advances in high-resolution microscopy and imaging techniques, the complex process of bundles formation and the multiple forms of physiological bundles are beginning to be better understood. Here, we review the physiochemical and biological properties of four families of highly conserved and abundant actin-bundling proteins, namely, α-actinin, fimbrin/plastin, fascin, and espin. We describe the similarities and differences between these proteins, their role in the formation of physiological actin bundles, and their properties-both related and unrelated to their bundling abilities. We also review some aspects of the general mechanism of actin bundles formation, which are known from the available information on the activity of the key actin partners involved in this process.
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Affiliation(s)
- Sudeepa Rajan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH 43210, USA
| | - Emil Reisler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
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11
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Silva AM, Chan FY, Norman MJ, Sobral AF, Zanin E, Gassmann R, Belmonte JM, Carvalho AX. β-heavy-spectrin stabilizes the constricting contractile ring during cytokinesis. J Cell Biol 2022; 222:213538. [PMID: 36219157 PMCID: PMC9559602 DOI: 10.1083/jcb.202202024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 08/17/2022] [Accepted: 09/20/2022] [Indexed: 11/22/2022] Open
Abstract
Cytokinesis requires the constriction of an actomyosin-based contractile ring and involves multiple F-actin crosslinkers. We show that partial depletion of the C. elegans cytokinetic formin generates contractile rings with low F-actin levels that constrict but are structurally fragile, and we use this background to investigate the roles of the crosslinkers plastin/PLST-1 and β-heavy-spectrin/SMA-1 during ring constriction. We show that the removal of PLST-1 or SMA-1 has opposite effects on the structural integrity of fragile rings. PLST-1 loss reduces cortical tension that resists ring constriction and makes fragile rings less prone to ruptures and regressions, whereas SMA-1 loss exacerbates structural defects, leading to frequent ruptures and cytokinesis failure. Fragile rings without SMA-1 or containing a shorter SMA-1, repeatedly rupture at the same site, and SMA-1::GFP accumulates at repair sites in fragile rings and in rings cut by laser microsurgery. These results establish that β-heavy-spectrin stabilizes the constricting ring and reveals the importance of β-heavy-spectrin size for network connectivity at low F-actin density.
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Affiliation(s)
- Ana Marta Silva
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Fung-Yi Chan
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Michael J. Norman
- Department of Physics, North Carolina State University, Raleigh, NC,Quantitative and Computational Developmental Biology Cluster, North Carolina State University, Raleigh, NC
| | - Ana Filipa Sobral
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Esther Zanin
- Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Reto Gassmann
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Julio Monti Belmonte
- Department of Physics, North Carolina State University, Raleigh, NC,Quantitative and Computational Developmental Biology Cluster, North Carolina State University, Raleigh, NC
| | - Ana Xavier Carvalho
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal,Correspondence to Ana Xavier Carvalho:
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12
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Zhang Y, An B, Wang W, Zhang B, He C, Luo H, Wang Q. Actin-bundling protein fimbrin regulates pathogenicity via organizing F-actin dynamics during appressorium development in Colletotrichum gloeosporioides. MOLECULAR PLANT PATHOLOGY 2022; 23:1472-1486. [PMID: 35791045 PMCID: PMC9452767 DOI: 10.1111/mpp.13242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
Anthracnose caused by Colletotrichum gloeosporioides leads to serious economic loss to rubber tree yield and other tropical crops. The appressorium, a specialized dome-shaped infection structure, plays a crucial role in the pathogenesis of C. gloeosporioides. However, the mechanism of how actin cytoskeleton dynamics regulate appressorium formation and penetration remains poorly defined in C. gloeosporioides. In this study, an actin cross-linking protein fimbrin homologue (CgFim1) was identified in C. gloeosporioides, and the knockout of CgFim1 led to impairment in vegetative growth, conidiation, and pathogenicity. We then investigated the roles of CgFim1 in the dynamic organization of the actin cytoskeleton. We observed that actin patches and cables localized at the apical and subapical regions of the hyphal tip, and showed a disc-to-ring dynamic around the pore during appressorium development. CgFim1 showed a similar distribution pattern to the actin cytoskeleton. Moreover, knockout of CgFim1 affected the polarity of the actin cytoskeleton in the hyphal tip and disrupted the actin dynamics and ring structure formation in the appressorium, which prevented polar growth and appressorium development. The CgFim1 mutant also interfered with the septin structure formation. This caused defects in pore wall overlay formation, pore contraction, and the extension of the penetration peg. These results reveal the mechanism by which CgFim1 regulates the growth and pathogenicity of C. gloeosporioides by organizing the actin cytoskeleton.
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Affiliation(s)
- Yi Zhang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
- Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed LaboratorySanyaChina
| | - Bang An
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
- Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed LaboratorySanyaChina
| | - Wenfeng Wang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
| | - Bei Zhang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
- Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed LaboratorySanyaChina
| | - Chaozu He
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
- Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed LaboratorySanyaChina
| | - Hongli Luo
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
- Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed LaboratorySanyaChina
| | - Qiannan Wang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
- Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed LaboratorySanyaChina
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13
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Hatano T, Lim TC, Billault-Chaumartin I, Dhar A, Gu Y, Massam-Wu T, Scott W, Adishesha S, Chapa-y-Lazo B, Springall L, Sivashanmugam L, Mishima M, Martin SG, Oliferenko S, Palani S, Balasubramanian MK. mNG-tagged fusion proteins and nanobodies to visualize tropomyosins in yeast and mammalian cells. J Cell Sci 2022; 135:jcs260288. [PMID: 36148799 PMCID: PMC9592052 DOI: 10.1242/jcs.260288] [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: 05/27/2022] [Accepted: 08/15/2022] [Indexed: 11/20/2022] Open
Abstract
Tropomyosins are structurally conserved α-helical coiled-coil proteins that bind along the length of filamentous actin (F-actin) in fungi and animals. Tropomyosins play essential roles in the stability of actin filaments and in regulating myosin II contractility. Despite the crucial role of tropomyosin in actin cytoskeletal regulation, in vivo investigations of tropomyosin are limited, mainly due to the suboptimal live-cell imaging tools currently available. Here, we report on an mNeonGreen (mNG)-tagged tropomyosin, with native promoter and linker length configuration, that clearly reports tropomyosin dynamics in Schizosaccharomyces pombe (Cdc8), Schizosaccharomyces japonicus (Cdc8) and Saccharomyces cerevisiae (Tpm1 and Tpm2). We also describe a fluorescent probe to visualize mammalian tropomyosin (TPM2 isoform). Finally, we generated a camelid nanobody against S. pombe Cdc8, which mimics the localization of mNG-Cdc8 in vivo. Using these tools, we report the presence of tropomyosin in previously unappreciated patch-like structures in fission and budding yeasts, show flow of tropomyosin (F-actin) cables to the cytokinetic actomyosin ring and identify rearrangements of the actin cytoskeleton during mating. These powerful tools and strategies will aid better analyses of tropomyosin and F-actin cables in vivo.
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Affiliation(s)
- Tomoyuki Hatano
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, Warwick CV4 7AL, UK
| | - Tzer Chyn Lim
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, Warwick CV4 7AL, UK
| | - Ingrid Billault-Chaumartin
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Anubhav Dhar
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Ying Gu
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London, SE1 1UL, UK
| | - Teresa Massam-Wu
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, Warwick CV4 7AL, UK
| | - William Scott
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, Warwick CV4 7AL, UK
| | - Sushmitha Adishesha
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Bernardo Chapa-y-Lazo
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, Warwick CV4 7AL, UK
| | - Luke Springall
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, Warwick CV4 7AL, UK
| | - Lavanya Sivashanmugam
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, Warwick CV4 7AL, UK
| | - Masanori Mishima
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, Warwick CV4 7AL, UK
| | - Sophie G. Martin
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Snezhana Oliferenko
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London, SE1 1UL, UK
| | - Saravanan Palani
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Mohan K. Balasubramanian
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, Warwick CV4 7AL, UK
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14
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Abstract
To fulfill the cytoskeleton’s diverse functions in cell mechanics and motility, actin networks with specialized architectures are built by cross-linking proteins. How these cross-linkers specify cytoskeletal network geometry is poorly understood at the level of protein structure. Here, we introduce a machine-learning–enabled pipeline for visualizing cross-linkers bridging cytoskeletal filaments with cryogenic electron microscopy (cryo-EM). We apply our method to T-plastin, a member of the evolutionarily conserved plastin/fimbrin family, revealing a sequence of conformational changes that enables T-plastin to bridge pairs of actin filaments in both parallel and antiparallel orientations. This provides a structural framework for understanding how plastins can generate actin networks featuring mixed filament polarity. To orchestrate cell mechanics, trafficking, and motility, cytoskeletal filaments must assemble into higher-order networks whose local subcellular architecture and composition specify their functions. Cross-linking proteins bridge filaments at the nanoscale to control a network’s μm-scale geometry, thereby conferring its mechanical properties and functional dynamics. While these interfilament linkages are key determinants of cytoskeletal function, their structural mechanisms remain poorly understood. Plastins/fimbrins are an evolutionarily ancient family of tandem calponin-homology domain (CHD) proteins required to construct multiple classes of actin networks, which feature diverse geometries specialized to power cytokinesis, microvilli and stereocilia biogenesis, and persistent cell migration. Here, we focus on the structural basis of actin network assembly by human T-plastin, a ubiquitously expressed isoform necessary for the maintenance of stable cellular protrusions generated by actin polymerization forces. By implementing a machine-learning–enabled cryo-electron microscopy pipeline for visualizing cross-linkers bridging multiple filaments, we uncover a sequential bundling mechanism enabling T-plastin to bridge pairs of actin filaments in both parallel and antiparallel orientations. T-plastin populates distinct structural landscapes in these two bridging orientations that are selectively compatible with actin networks featuring divergent architectures and functions. Our structural, biochemical, and cell biological data highlight inter-CHD linkers as key structural elements underlying flexible but stable cross-linking that are likely to be disrupted by T-plastin mutations that cause hereditary bone diseases.
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15
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Zheng Z, Liu H, Shi Y, Liu Z, Teng H, Deng S, Wei L, Wang Y, Zhang F. Comparative transcriptome analysis reveals the resistance regulation mechanism and fungicidal activity of the fungicide phenamacril in Fusarium oxysporum. Sci Rep 2022; 12:11081. [PMID: 35773469 PMCID: PMC9247061 DOI: 10.1038/s41598-022-15188-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 06/20/2022] [Indexed: 12/21/2022] Open
Abstract
Fusarium oxysporum (Fo) is an important species complex of soil-borne pathogenic fungi that cause vascular wilt diseases of agricultural crops and some opportunistic diseases of humans. The fungicide phenamacril has been extensively reported to have antifungal activity against Fusarium graminearum and Fusarium fujikuroi. In this study, we found that the amino acid substitutions (V151A and S418T) in Type I myosin FoMyo5 cause natural low resistance to phenamacril in the plant pathogenic Fo isolates. Therefore, we compared the transcriptomes of two phenamacril-resistant Fo isolates FoII5, Fo1st and one phenamacril-sensitive isolate Fo3_a after 1 μg/mL phenamacril treatment. Among the 2728 differentially expressed genes (DEGs), 14 DEGs involved in oxidation–reduction processes and MFS transporters, were significantly up-regulated in phenamacril-resistant isolates. On the other hand, 14 DEGs involved in ATP-dependent RNA helicase and ribosomal biogenesis related proteins, showed significantly down-regulated expression in both phenamacril-resistant and -sensitive isolates. These results indicated that phenamacril not only seriously affected the cytoskeletal protein binding and ATPase activity of sensitive isolate, but also suppressed ribosome biogenesis in all the isolates. Hence, this study helps us better understand resistance regulation mechanism and fungicidal activity of phenamacril and provide reference for the development of new fungicides to control Fo.
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Affiliation(s)
- Zhitian Zheng
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, People's Republic of China.
| | - Huaqi Liu
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, People's Republic of China
| | - Yunyong Shi
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, People's Republic of China
| | - Zao Liu
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, People's Republic of China
| | - Hui Teng
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, People's Republic of China
| | - Sheng Deng
- Institute of Plant Protection, Key Lab of Food Quality and Safety of Jiangsu Province-State, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, People's Republic of China.
| | - Lihui Wei
- Institute of Plant Protection, Key Lab of Food Quality and Safety of Jiangsu Province-State, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, People's Republic of China
| | - Yunpeng Wang
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, People's Republic of China.
| | - Feng Zhang
- Key Laboratory of Pesticide, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
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16
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Allosteric regulation controls actin-bundling properties of human plastins. Nat Struct Mol Biol 2022; 29:519-528. [PMID: 35589838 DOI: 10.1038/s41594-022-00771-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/05/2022] [Indexed: 11/08/2022]
Abstract
Plastins/fimbrins are conserved actin-bundling proteins contributing to motility, cytokinesis and other cellular processes by organizing strikingly different actin assemblies as in aligned bundles and branched networks. We propose that this ability of human plastins stems from an allosteric communication between their actin-binding domains (ABD1/2) engaged in a tight spatial association. Here we show that ABD2 can bind actin three orders of magnitude stronger than ABD1, unless the domains are involved in an equally strong inhibitory engagement. A mutation mimicking physiologically relevant phosphorylation at the ABD1-ABD2 interface greatly weakened their association, dramatically potentiating actin cross-linking. Cryo-EM reconstruction revealed the ABD1-actin interface and enabled modeling of the plastin bridge and domain separation in parallel bundles. We predict that a strong and tunable allosteric inhibition between the domains allows plastins to modulate the cross-linking strength, contributing to remodeling of actin assemblies of different morphologies defining the unique place of plastins in actin organization.
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17
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Abouelezz A, Almeida-Souza L. The mammalian endocytic cytoskeleton. Eur J Cell Biol 2022; 101:151222. [DOI: 10.1016/j.ejcb.2022.151222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 12/27/2022] Open
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18
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Reda B, Alphée M, Julien H, Olivia DR. Non-linear elastic properties of actin patches to partially rescue yeast endocytosis efficiency in the absence of the cross-linker Sac6. SOFT MATTER 2022; 18:1479-1488. [PMID: 35088793 DOI: 10.1039/d1sm01437d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Clathrin mediated endocytosis is an essential and complex cellular process involving more than 60 proteins. In yeast, successful endocytosis requires counteracting a large turgor pressure. To this end, yeasts assemble actin patches, which accumulate elastic energy during their assembly. We investigated the material properties of reconstituted actin patches from a wild-type (WT) strain and a mutant strain lacking the cross-linker Sac6 (sac6Δ), which has reduced endocytosis efficiency in live cells. We hypothesized that a change in the viscous properties of the actin patches, which would dissipate more mechanical energy, could explain this reduced efficiency. There was however no significant difference in the viscosity of both types of patches. However, we discovered a significantly different non-linear elastic response. While WT patches had a constant elastic modulus at different stress values, sac6Δ patches had a lower elastic modulus at low stress, before stiffening at higher ones, up to values similar to those of WT patches. To understand the consequences of this discovery, we performed, in vivo, a precise analysis of actin patch dynamics. Our analysis reveals that a small fraction of actin patches successfully complete endocytosis in sac6Δ cells, provided that those assemble an excess of actin at the membrane compared to WT. This observation indicates that the non-linear elastic properties of actin networks in sac6Δ cells contribute to rescue endocytosis, requiring nevertheless more actin material to build-up the necessary stored elastic energy.
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Affiliation(s)
- Belbahri Reda
- PMMH, CNRS, ESPCI Paris, Université PSL, Sorbonne Université, Université de Paris, Paris, France.
- Aix Marseille Univ, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
| | - Michelot Alphée
- Aix Marseille Univ, CNRS, IBDM, Turing Centre for Living Systems, Marseille, France
| | - Heuvingh Julien
- PMMH, CNRS, ESPCI Paris, Université PSL, Sorbonne Université, Université de Paris, Paris, France.
| | - du Roure Olivia
- PMMH, CNRS, ESPCI Paris, Université PSL, Sorbonne Université, Université de Paris, Paris, France.
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19
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Lemière J, Ren Y, Berro J. Rapid adaptation of endocytosis, exocytosis and eisosomes after an acute increase in membrane tension in yeast cells. eLife 2021; 10:62084. [PMID: 33983119 PMCID: PMC9045820 DOI: 10.7554/elife.62084] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 05/12/2021] [Indexed: 11/13/2022] Open
Abstract
During clathrin-mediated endocytosis (CME) in eukaryotes, actin assembly is required to overcome large membrane tension and turgor pressure. However, the molecular mechanisms by which the actin machinery adapts to varying membrane tension remain unknown. In addition, how cells reduce their membrane tension when they are challenged by hypotonic shocks remains unclear. We used quantitative microscopy to demonstrate that cells rapidly reduce their membrane tension using three parallel mechanisms. In addition to using their cell wall for mechanical protection, yeast cells disassemble eisosomes to buffer moderate changes in membrane tension on a minute time scale. Meanwhile, a temporary reduction in the rate of endocytosis for 2–6 min and an increase in the rate of exocytosis for at least 5 min allow cells to add large pools of membrane to the plasma membrane. We built on these results to submit the cells to abrupt increases in membrane tension and determine that the endocytic actin machinery of fission yeast cells rapidly adapts to perform CME. Our study sheds light on the tight connection between membrane tension regulation, endocytosis, and exocytosis.
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Affiliation(s)
- Joël Lemière
- Department of Molecular Biophysics and Biochemistry, Department of Cell Biology, Yale University, New Haven, United States
| | - Yuan Ren
- Department of Molecular Biophysics and Biochemistry, Department of Cell Biology, Yale University, New Haven, United States
| | - Julien Berro
- Department of Molecular Biophysics and Biochemistry, Department of Cell Biology, Yale University, New Haven, United States
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20
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Schwebach CL, Kudryashova E, Kudryashov DS. Plastin 3 in X-Linked Osteoporosis: Imbalance of Ca 2+-Dependent Regulation Is Equivalent to Protein Loss. Front Cell Dev Biol 2021; 8:635783. [PMID: 33553175 PMCID: PMC7859272 DOI: 10.3389/fcell.2020.635783] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 12/28/2020] [Indexed: 12/14/2022] Open
Abstract
Osteogenesis imperfecta is a genetic disorder disrupting bone development and remodeling. The primary causes of osteogenesis imperfecta are pathogenic variants of collagen and collagen processing genes. However, recently variants of the actin bundling protein plastin 3 have been identified as another source of osteogenesis imperfecta. Plastin 3 is a highly conserved protein involved in several important cellular structures and processes and is controlled by intracellular Ca2+ which potently inhibits its actin-bundling activity. The precise mechanisms by which plastin 3 causes osteogenesis imperfecta remain unclear, but recent advances have contributed to our understanding of bone development and the actin cytoskeleton. Here, we review the link between plastin 3 and osteogenesis imperfecta highlighting in vitro studies and emphasizing the importance of Ca2+ regulation in the localization and functionality of plastin 3.
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Affiliation(s)
- Christopher L Schwebach
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, United States
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, United States
| | - Dmitri S Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, United States
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21
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Higaki T, Akita K, Katoh K. Coefficient of variation as an image-intensity metric for cytoskeleton bundling. Sci Rep 2020; 10:22187. [PMID: 33349642 PMCID: PMC7752905 DOI: 10.1038/s41598-020-79136-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/27/2020] [Indexed: 12/17/2022] Open
Abstract
The evaluation of cytoskeletal bundling is a fundamental experimental method in the field of cell biology. Although the skewness of the pixel intensity distribution derived from fluorescently-labeled cytoskeletons has been widely used as a metric to evaluate the degree of bundling in digital microscopy images, its versatility has not been fully validated. Here, we applied the coefficient of variation (CV) of intensity values as an alternative metric, and compared its performance with skewness. In synthetic images representing extremely bundled conditions, the CV successfully detected degrees of bundling that could not be distinguished by skewness. On actual microscopy images, CV was better than skewness, especially on variable-angle epifluorescence microscopic images or stimulated emission depletion and confocal microscopy images of very small areas of around 1 μm2. When blur or noise was added to synthetic images, CV was found to be robust to blur but deleteriously affected by noise, whereas skewness was robust to noise but deleteriously affected by blur. For confocal images, CV and skewness showed similar sensitivity to noise, possibly because optical blurring is often present in microscopy images. Therefore, in practical use with actual microscopy images, CV may be more appropriate than skewness, unless the image is extremely noisy.
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Affiliation(s)
- Takumi Higaki
- International Research Organization for Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto, Japan.
| | - Kae Akita
- Department of Chemical Biological Science, Faculty of Science, Japan Women's University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo, Japan
| | - Kaoru Katoh
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
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22
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Leite J, Chan FY, Osório DS, Saramago J, Sobral AF, Silva AM, Gassmann R, Carvalho AX. Equatorial Non-muscle Myosin II and Plastin Cooperate to Align and Compact F-actin Bundles in the Cytokinetic Ring. Front Cell Dev Biol 2020; 8:573393. [PMID: 33102479 PMCID: PMC7546906 DOI: 10.3389/fcell.2020.573393] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 09/03/2020] [Indexed: 12/17/2022] Open
Abstract
Cytokinesis is the last step of cell division that physically partitions the mother cell into two daughter cells. Cytokinesis requires the assembly and constriction of a contractile ring, a circumferential array of filamentous actin (F-actin), non-muscle myosin II motors (myosin), and actin-binding proteins that forms at the cell equator. Cytokinesis is accompanied by long-range cortical flows from regions of relaxation toward regions of compression. In the C. elegans one-cell embryo, it has been suggested that anterior-directed cortical flows are the main driver of contractile ring assembly. Here, we use embryos co-expressing motor-dead and wild-type myosin to show that cortical flows can be severely reduced without major effects on contractile ring assembly and timely completion of cytokinesis. Fluorescence recovery after photobleaching in the ingressing furrow reveals that myosin recruitment kinetics are also unaffected by the absence of cortical flows. We find that myosin cooperates with the F-actin crosslinker plastin to align and compact F-actin bundles at the cell equator, and that this cross-talk is essential for cytokinesis. Our results thus argue against the idea that cortical flows are a major determinant of contractile ring assembly. Instead, we propose that contractile ring assembly requires localized concerted action of motor-competent myosin and plastin at the cell equator.
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Affiliation(s)
- Joana Leite
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Fung-Yi Chan
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Daniel S Osório
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Joana Saramago
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Ana F Sobral
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Ana M Silva
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Reto Gassmann
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Ana X Carvalho
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
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23
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Schuster M, Steinberg G. The fungicide dodine primarily inhibits mitochondrial respiration in Ustilago maydis, but also affects plasma membrane integrity and endocytosis, which is not found in Zymoseptoria tritici. Fungal Genet Biol 2020; 142:103414. [PMID: 32474016 PMCID: PMC7526662 DOI: 10.1016/j.fgb.2020.103414] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 05/22/2020] [Accepted: 05/23/2020] [Indexed: 11/03/2022]
Abstract
Early reports in the fungus Ustilago maydis suggest that the amphipathic fungicide dodine disrupts the fungal plasma membrane (PM), thereby killing this corn smut pathogen. However, a recent study in the wheat pathogen Zymoseptoria tritici does not support such mode of action (MoA). Instead, dodine inhibits mitochondrial ATP-synthesis, both in Z. tritici and U. maydis. This casts doubt on an fungicidal activity of dodine at the PM. Here, we use a cell biological approach and investigate further the effect of dodine on the plasma membrane in both fungi. We show that dodine indeed breaks the integrity of the PM in U. maydis, indicated by a concentration-dependent cell depolarization. In addition, the fungicide reduces PM fluidity and arrests endocytosis by inhibiting the internalization of endocytic vesicles at the PM. This is likely due to impaired recruitment of the actin-crosslinker fimbrin to endocytic actin patches. However, quantitative data reveal that the effect on mitochondria represents the primary MoA in U. maydis. None of these plasma membrane-associated effects were found in dodine-treated Z. tritici cells. Thus, the physiological effect of an anti-fungal chemistry can differ between pathogens. This merits consideration when characterizing a given fungicide.
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Affiliation(s)
- Martin Schuster
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Gero Steinberg
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK; University of Utrecht, Padualaan 8, Utrecht 3584 CH, The Netherlands.
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24
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Schwebach CL, Kudryashova E, Zheng W, Orchard M, Smith H, Runyan LA, Egelman EH, Kudryashov DS. Osteogenesis imperfecta mutations in plastin 3 lead to impaired calcium regulation of actin bundling. Bone Res 2020; 8:21. [PMID: 32509377 PMCID: PMC7244493 DOI: 10.1038/s41413-020-0095-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 02/06/2020] [Accepted: 03/23/2020] [Indexed: 12/11/2022] Open
Abstract
Mutations in actin-bundling protein plastin 3 (PLS3) emerged as a cause of congenital osteoporosis, but neither the role of PLS3 in bone development nor the mechanisms underlying PLS3-dependent osteoporosis are understood. Of the over 20 identified osteoporosis-linked PLS3 mutations, we investigated all five that are expected to produce full-length protein. One of the mutations distorted an actin-binding loop in the second actin-binding domain of PLS3 and abolished F-actin bundling as revealed by cryo-EM reconstruction and protein interaction assays. Surprisingly, the remaining four mutants fully retained F-actin bundling ability. However, they displayed defects in Ca2+ sensitivity: two of the mutants lost the ability to be inhibited by Ca2+, while the other two became hypersensitive to Ca2+. Each group of the mutants with similar biochemical properties showed highly characteristic cellular behavior. Wild-type PLS3 was distributed between lamellipodia and focal adhesions. In striking contrast, the Ca2+-hyposensitive mutants were not found at the leading edge but localized exclusively at focal adhesions/stress fibers, which displayed reinforced morphology. Consistently, the Ca2+-hypersensitive PLS3 mutants were restricted to lamellipodia, while chelation of Ca2+ caused their redistribution to focal adhesions. Finally, the bundling-deficient mutant failed to co-localize with any F-actin structures in cells despite a preserved F-actin binding through a non-mutation-bearing actin-binding domain. Our findings revealed that severe osteoporosis can be caused by a mutational disruption of the Ca2+-controlled PLS3's cycling between adhesion complexes and the leading edge. Integration of the structural, biochemical, and cell biology insights enabled us to propose a molecular mechanism of plastin activity regulation by Ca2+.
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Affiliation(s)
- Christopher L. Schwebach
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
- Molecular Cellular and Developmental Biology graduate program, The Ohio State University, Columbus, OH 43210 USA
| | - Elena Kudryashova
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
| | - Weili Zheng
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908 USA
| | - Matthew Orchard
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
| | - Harper Smith
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
- Biophysics graduate program, The Ohio State University, Columbus, OH 43210 USA
| | - Lucas A. Runyan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
| | - Edward H. Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908 USA
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210 USA
- Molecular Cellular and Developmental Biology graduate program, The Ohio State University, Columbus, OH 43210 USA
- Biophysics graduate program, The Ohio State University, Columbus, OH 43210 USA
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25
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Li YB, Xu R, Liu C, Shen N, Han LB, Tang D. Magnaporthe oryzae fimbrin organizes actin networks in the hyphal tip during polar growth and pathogenesis. PLoS Pathog 2020; 16:e1008437. [PMID: 32176741 PMCID: PMC7098657 DOI: 10.1371/journal.ppat.1008437] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 03/26/2020] [Accepted: 02/26/2020] [Indexed: 01/19/2023] Open
Abstract
Magnaporthe oryzae causes rice blast disease, but little is known about the dynamic restructuring of the actin cytoskeleton during its polarized tip growth and pathogenesis. Here, we used super-resolution live-cell imaging to investigate the dynamic organization of the actin cytoskeleton in M. oryzae during hyphal tip growth and pathogenesis. We observed a dense actin network at the apical region of the hyphae and actin filaments originating from the Spitzenkörper (Spk, the organizing center for hyphal growth and development) that formed branched actin bundles radiating to the cell membrane. The actin cross-linking protein Fimbrin (MoFim1) helps organize this actin distribution. MoFim1 localizes to the actin at the subapical collar, the actin bundles, and actin at the Spk. Knockout of MoFim1 resulted in impaired Spk maintenance and reduced actin bundle formation, preventing polar growth, vesicle transport, and the expansion of hyphae in plant cells. Finally, transgenic rice (Oryza sativa) expressing RNA hairpins targeting MoFim1 exhibited improved resistance to M. oryzae infection, indicating that MoFim1 represents an excellent candidate for M. oryzae control. These results reveal the dynamics of actin assembly in M. oryzae during hyphal tip development and pathogenesis, and they suggest a mechanism in which MoFim1 organizes such actin networks.
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Affiliation(s)
- Yuan-Bao Li
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Rui Xu
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Chengyu Liu
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Ningning Shen
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Li-Bo Han
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Dingzhong Tang
- State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
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26
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How Actin Tracks Affect Myosin Motors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1239:183-197. [DOI: 10.1007/978-3-030-38062-5_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
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27
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Matsuda K, Sugawa M, Yamagishi M, Kodera N, Yajima J. Visualizing dynamic actin cross‐linking processes driven by the actin‐binding protein anillin. FEBS Lett 2019; 594:1237-1247. [DOI: 10.1002/1873-3468.13720] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 11/26/2019] [Accepted: 12/09/2019] [Indexed: 01/16/2023]
Affiliation(s)
- Kyohei Matsuda
- Department of Life Sciences Graduate School of Arts and Sciences The University of Tokyo Japan
| | - Mitsuhiro Sugawa
- Department of Life Sciences Graduate School of Arts and Sciences The University of Tokyo Japan
- Komaba Institute for Science The University of Tokyo Japan
| | - Masahiko Yamagishi
- Department of Life Sciences Graduate School of Arts and Sciences The University of Tokyo Japan
- Komaba Institute for Science The University of Tokyo Japan
| | - Noriyuki Kodera
- Nano Life Science Institute (WPI‐NanoLSI) Kanazawa University Japan
| | - Junichiro Yajima
- Department of Life Sciences Graduate School of Arts and Sciences The University of Tokyo Japan
- Komaba Institute for Science The University of Tokyo Japan
- Research Center for Complex Systems Biology The University of Tokyo Japan
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28
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External signal-mediated polarized growth in fungi. Curr Opin Cell Biol 2019; 62:150-158. [PMID: 31875532 DOI: 10.1016/j.ceb.2019.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/28/2019] [Accepted: 11/04/2019] [Indexed: 12/13/2022]
Abstract
As the majority of fungi are nonmotile, polarized growth in response to an external signal enables them to search for nutrients and mating partners, and hence is crucial for survival and proliferation. Although the mechanisms underlying polarization in response to external signals has commonalities with polarization during mitotic division, during budding, and fission growth, the importance of diverse feedback loops regulating external signal-mediated polarized growth is likely to be distinct and uniquely adapted to a dynamic environment. Here, we highlight recent advances in our understanding of the mechanisms that are crucial for polarity in response to external signals in fungi, with particular focus on the roles of membrane traffic, small GTPases, and lipids, as well as the interplay between cell shape and cell growth.
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29
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Lacy MM, Baddeley D, Berro J. Single-molecule turnover dynamics of actin and membrane coat proteins in clathrin-mediated endocytosis. eLife 2019; 8:52355. [PMID: 31855180 PMCID: PMC6977972 DOI: 10.7554/elife.52355] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/18/2019] [Indexed: 12/22/2022] Open
Abstract
Actin dynamics generate forces to deform the membrane and overcome the cell’s high turgor pressure during clathrin-mediated endocytosis (CME) in yeast, but precise molecular details are still unresolved. Our previous models predicted that actin filaments of the endocytic meshwork continually polymerize and disassemble, turning over multiple times during an endocytic event, similar to other actin systems. We applied single-molecule speckle tracking in live fission yeast to directly measure molecular turnover within CME sites for the first time. In contrast with the overall ~20 s lifetimes of actin and actin-associated proteins in endocytic patches, we detected single-molecule residence times around 1 to 2 s, and similarly high turnover rates of membrane-associated proteins in CME. Furthermore, we find heterogeneous behaviors in many proteins’ motions. These results indicate that endocytic proteins turn over up to five times during the formation of an endocytic vesicle, and suggest revising quantitative models of force production.
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Affiliation(s)
- Michael M Lacy
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.,Nanobiology Institute, Yale University, West Haven, United States.,Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, United States
| | - David Baddeley
- Nanobiology Institute, Yale University, West Haven, United States.,Department of Cell Biology, Yale University School of Medicine, New Haven, United States
| | - Julien Berro
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.,Nanobiology Institute, Yale University, West Haven, United States.,Department of Cell Biology, Yale University School of Medicine, New Haven, United States
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30
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Lacy MM, Baddeley D, Berro J. Single-molecule turnover dynamics of actin and membrane coat proteins in clathrin-mediated endocytosis. eLife 2019; 8. [PMID: 31855180 DOI: 10.1101/617746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/18/2019] [Indexed: 05/20/2023] Open
Abstract
Actin dynamics generate forces to deform the membrane and overcome the cell's high turgor pressure during clathrin-mediated endocytosis (CME) in yeast, but precise molecular details are still unresolved. Our previous models predicted that actin filaments of the endocytic meshwork continually polymerize and disassemble, turning over multiple times during an endocytic event, similar to other actin systems. We applied single-molecule speckle tracking in live fission yeast to directly measure molecular turnover within CME sites for the first time. In contrast with the overall ~20 s lifetimes of actin and actin-associated proteins in endocytic patches, we detected single-molecule residence times around 1 to 2 s, and similarly high turnover rates of membrane-associated proteins in CME. Furthermore, we find heterogeneous behaviors in many proteins' motions. These results indicate that endocytic proteins turn over up to five times during the formation of an endocytic vesicle, and suggest revising quantitative models of force production.
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Affiliation(s)
- Michael M Lacy
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
- Nanobiology Institute, Yale University, West Haven, United States
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, United States
| | - David Baddeley
- Nanobiology Institute, Yale University, West Haven, United States
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States
| | - Julien Berro
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
- Nanobiology Institute, Yale University, West Haven, United States
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States
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31
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Mechanical stiffness of reconstituted actin patches correlates tightly with endocytosis efficiency. PLoS Biol 2019; 17:e3000500. [PMID: 31652255 PMCID: PMC6834286 DOI: 10.1371/journal.pbio.3000500] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/06/2019] [Accepted: 10/18/2019] [Indexed: 01/16/2023] Open
Abstract
Clathrin-mediated endocytosis involves the sequential assembly of more than 60 proteins at the plasma membrane. An important fraction of these proteins regulates the assembly of an actin-related protein 2/3 (Arp2/3)-branched actin network, which is essential to generate the force during membrane invagination. We performed, on wild-type (WT) yeast and mutant strains lacking putative actin crosslinkers, a side-by-side comparison of in vivo endocytic phenotypes and in vitro rigidity measurements of reconstituted actin patches. We found a clear correlation between softer actin networks and a decreased efficiency of endocytosis. Our observations support a chain-of-consequences model in which loss of actin crosslinking softens Arp2/3-branched actin networks, directly limiting the transmission of the force. Additionally, the lifetime of failed endocytic patches increases, leading to a larger number of patches and a reduced pool of polymerizable actin, which slows down actin assembly and further impairs endocytosis. This study uses in vitro reconstitution of endocytic actin patches and mechanical measurements with chains of superparamagnetic microbeads to reveal a tight correlation between the stiffness of actin networks and the efficiency of endocytosis in yeast.
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32
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Billault-Chaumartin I, Martin SG. Capping Protein Insulates Arp2/3-Assembled Actin Patches from Formins. Curr Biol 2019; 29:3165-3176.e6. [PMID: 31495586 PMCID: PMC6864609 DOI: 10.1016/j.cub.2019.07.088] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/04/2019] [Accepted: 07/30/2019] [Indexed: 12/13/2022]
Abstract
How actin structures of distinct identities and functions coexist within the same environment is a critical self-organization question. Fission yeast cells have a simple actin cytoskeleton made of four structures: Arp2/3 assembles actin patches around endocytic pits, and the formins For3, Cdc12, and Fus1 assemble actin cables, the cytokinetic ring during division, and the fusion focus during sexual reproduction, respectively. The focus concentrates the delivery of hydrolases by myosin V to digest the cell wall for cell fusion. We discovered that cells lacking capping protein (CP), a heterodimer that blocks barbed-end dynamics and associates with actin patches, exhibit a delay in fusion. Consistent with CP-formin competition for barbed-end binding, Fus1, F-actin, and the linear filament marker tropomyosin hyper-accumulate at the fusion focus in cells lacking CP. CP deletion also rescues the fusion defect of a mutation in the Fus1 knob region. However, myosin V and exocytic cargoes are reduced at the fusion focus and diverted to ectopic foci, which underlies the fusion defect. Remarkably, the ectopic foci coincide with Arp2/3-assembled actin patches, which now contain low levels of Fus1. We further show that CP localization to actin patches is required to prevent the formation of ectopic foci and promote efficient cell fusion. During mitotic growth, actin patches lacking CP similarly display a dual identity, as they accumulate the formins For3 and Cdc12, normally absent from patches, and are co-decorated by the linear filament-binding protein tropomyosin and the patch marker fimbrin. Thus, CP serves to protect Arp2/3-nucleated structures from formin activity.
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Affiliation(s)
- Ingrid Billault-Chaumartin
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Sophie G Martin
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland.
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33
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Microridges are apical epithelial projections formed of F-actin networks that organize the glycan layer. Sci Rep 2019; 9:12191. [PMID: 31434932 PMCID: PMC6704121 DOI: 10.1038/s41598-019-48400-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 07/29/2019] [Indexed: 11/16/2022] Open
Abstract
Apical projections are integral functional units of epithelial cells. Microvilli and stereocilia are cylindrical apical projections that are formed of bundled actin. Microridges on the other hand, extend laterally, forming labyrinthine patterns on surfaces of various kinds of squamous epithelial cells. So far, the structural organization and functions of microridges have remained elusive. We have analyzed microridges on zebrafish epidermal cells using confocal and electron microscopy methods including electron tomography, to show that microridges are formed of F-actin networks and require the function of the Arp2/3 complex for their maintenance. During development, microridges begin as F-actin punctae showing signatures of branching and requiring an active Arp2/3 complex. Using inhibitors of actin polymerization and the Arp2/3 complex, we show that microridges organize the surface glycan layer. Our analyses have unraveled the F-actin organization supporting the most abundant and evolutionarily conserved apical projection, which functions in glycan organization.
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34
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Christensen JR, Homa KE, Morganthaler AN, Brown RR, Suarez C, Harker AJ, O'Connell ME, Kovar DR. Cooperation between tropomyosin and α-actinin inhibits fimbrin association with actin filament networks in fission yeast. eLife 2019; 8:47279. [PMID: 31180322 PMCID: PMC6557641 DOI: 10.7554/elife.47279] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 05/29/2019] [Indexed: 11/13/2022] Open
Abstract
We previously discovered that competition between fission yeast actin binding proteins (ABPs) for binding F-actin facilitates their sorting to different cellular networks. Specifically, competition between endocytic actin patch ABPs fimbrin Fim1 and cofilin Adf1 enhances their activities, and prevents tropomyosin Cdc8's association with actin patches. However, these interactions do not explain how Fim1 is prevented from associating strongly with other F-actin networks such as the contractile ring. Here, we identified α-actinin Ain1, a contractile ring ABP, as another Fim1 competitor. Fim1 competes with Ain1 for association with F-actin, which is dependent upon their F-actin residence time. While Fim1 outcompetes both Ain1 and Cdc8 individually, Cdc8 enhances the F-actin bundling activity of Ain1, allowing Ain1 to generate F-actin bundles that Cdc8 can bind in the presence of Fim1. Therefore, the combination of contractile ring ABPs Ain1 and Cdc8 is capable of inhibiting Fim1's association with F-actin networks.
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Affiliation(s)
- Jenna R Christensen
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
| | - Kaitlin E Homa
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
| | - Alisha N Morganthaler
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
| | - Rachel R Brown
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
| | - Cristian Suarez
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
| | - Alyssa J Harker
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, United States
| | - Meghan E O'Connell
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States.,Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, United States
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35
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Fan YL, Zhao HC, Li B, Zhao ZL, Feng XQ. Mechanical Roles of F-Actin in the Differentiation of Stem Cells: A Review. ACS Biomater Sci Eng 2019; 5:3788-3801. [PMID: 33438419 DOI: 10.1021/acsbiomaterials.9b00126] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In the development and differentiation of stem cells, mechanical forces associated with filamentous actin (F-actin) play a crucial role. The present review aims to reveal the relationship among the chemical components, microscopic structures, mechanical properties, and biological functions of F-actin. Particular attention is given to the functions of the cytoplasmic and nuclear microfilament cytoskeleton and their regulation mechanisms in the differentiation of stem cells. The distributions of different types of actin monomers in mammal cells and the functions of actin-binding proteins are summarized. We discuss how the fate of stem cells is regulated by intra/extracellular mechanical and chemical cues associated with microfilament-related proteins, intercellular adhesion molecules, etc. In addition, we also address the differentiation-induced variation in the stiffness of stem cells and the correlation between the fate and geometric shape change of stem cells. This review not only deepens our understanding of the biophysical mechanisms underlying the fates of stem cells under different culture conditions but also provides inspirations for the tissue engineering of stem cells.
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Affiliation(s)
- Yan-Lei Fan
- Institute of Biomechanics and Medical Engineering, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Hu-Cheng Zhao
- Institute of Biomechanics and Medical Engineering, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Bo Li
- Institute of Biomechanics and Medical Engineering, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Zi-Long Zhao
- Institute of Biomechanics and Medical Engineering, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Xi-Qiao Feng
- Institute of Biomechanics and Medical Engineering, Applied Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
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36
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A Novel Actin Binding Drug with In Vivo Efficacy. Antimicrob Agents Chemother 2018; 63:AAC.01585-18. [PMID: 30323040 PMCID: PMC6325233 DOI: 10.1128/aac.01585-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 09/26/2018] [Indexed: 11/23/2022] Open
Abstract
Occidiofungin is produced by the soil bacterium Burkolderia contaminans MS14 and is structurally similar or identical to the burkholdines, xylocandins, and cepacidines. This study identified the primary cellular target of occidiofungin, which was determined to be actin. Occidiofungin is produced by the soil bacterium Burkolderia contaminans MS14 and is structurally similar or identical to the burkholdines, xylocandins, and cepacidines. This study identified the primary cellular target of occidiofungin, which was determined to be actin. The modification of occidiofungin with a functional alkyne group enabled affinity purification assays and localization studies in yeast. Occidiofungin has a subtle effect on actin dynamics that triggers apoptotic cell death. We demonstrate the highly specific localization of occidiofungin to cellular regions rich in actin in yeast and the binding of occidiofungin to purified actin in vitro. Furthermore, a disruption of actin-mediated cellular processes, such as endocytosis, nuclear segregation, and hyphal formation, was observed. All of these processes require the formation of stable actin cables, which are disrupted following the addition of a subinhibitory concentration of occidiofungin. We were also able to demonstrate the effectiveness of occidiofungin in treating a vulvovaginal yeast infection in a murine model. The results of this study are important for the development of an efficacious novel class of actin binding drugs that may fill the existing gap in treatment options for fungal infections or different types of cancer.
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O’Shaughnessy B, Thiyagarajan S. Mechanisms of contractile ring tension production and constriction. Biophys Rev 2018; 10:1667-1681. [PMID: 30456601 PMCID: PMC6297097 DOI: 10.1007/s12551-018-0476-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 10/23/2018] [Indexed: 12/24/2022] Open
Abstract
The contractile ring is a remarkable tension-generating cellular machine that constricts and divides cells into two during cytokinesis, the final stage of the cell cycle. Since the ring's discovery, the parallels with muscle have been emphasized. Both are contractile actomyosin machineries, and long ago, a muscle-like sliding filament mechanism was proposed for the ring. This review focuses on the mechanisms that generate ring tension and constrict contractile rings. The emphasis is on fission yeast, whose contractile ring is sufficiently well characterized that realistic mathematical models are feasible, and possible lessons from fission yeast that may apply to animal cells are discussed. Recent discoveries relevant to the organization in fission yeast rings suggest a stochastic steady-state version of the classic sliding filament mechanism for tension. The importance of different modes of anchoring for tension production and for organizational stability of constricting rings is discussed. Possible mechanisms are discussed that set the constriction rate and enable the contractile ring to meet the technical challenge of maintaining structural integrity and tension-generating capacity while continuously disassembling throughout constriction.
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Affiliation(s)
- Ben O’Shaughnessy
- Department of Chemical Engineering, Columbia University, New York, NY 10027 USA
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38
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Zhang S, Wang C, Xie M, Liu J, Kong Z, Su H. Actin Bundles in The Pollen Tube. Int J Mol Sci 2018; 19:ijms19123710. [PMID: 30469514 PMCID: PMC6321563 DOI: 10.3390/ijms19123710] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/18/2018] [Accepted: 11/19/2018] [Indexed: 12/31/2022] Open
Abstract
The angiosperm pollen tube delivers two sperm cells into the embryo sac through a unique growth strategy, named tip growth, to accomplish fertilization. A great deal of experiments have demonstrated that actin bundles play a pivotal role in pollen tube tip growth. There are two distinct actin bundle populations in pollen tubes: the long, rather thick actin bundles in the shank and the short, highly dynamic bundles near the apex. With the development of imaging techniques over the last decade, great breakthroughs have been made in understanding the function of actin bundles in pollen tubes, especially short subapical actin bundles. Here, we tried to draw an overall picture of the architecture, functions and underlying regulation mechanism of actin bundles in plant pollen tubes.
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Affiliation(s)
- Shujuan Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Chunbo Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Min Xie
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Jinyu Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Zhe Kong
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Hui Su
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
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39
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Tseng HY, Samarelli AV, Kammerer P, Scholze S, Ziegler T, Immler R, Zent R, Sperandio M, Sanders CR, Fässler R, Böttcher RT. LCP1 preferentially binds clasped αMβ2 integrin and attenuates leukocyte adhesion under flow. J Cell Sci 2018; 131:jcs.218214. [PMID: 30333137 DOI: 10.1242/jcs.218214] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 09/07/2018] [Indexed: 12/13/2022] Open
Abstract
Integrins are α/β heterodimers that interconvert between inactive and active states. In the active state the α/β cytoplasmic domains recruit integrin-activating proteins and separate the transmembrane and cytoplasmic (TMcyto) domains (unclasped TMcyto). Conversely, in the inactive state the α/β TMcyto domains bind integrin-inactivating proteins, resulting in the association of the TMcyto domains (clasped TMcyto). Here, we report the isolation of integrin cytoplasmic tail interactors using either lipid bicelle-incorporated integrin TMcyto domains (α5, αM, αIIb, β1, β2 and β3 integrin TMcyto) or a clasped, lipid bicelle-incorporated αMβ2 TMcyto. Among the proteins found to preferentially bind clasped rather than the isolated αM and β2 subunits was L-plastin (LCP1, also known as plastin-2), which binds to and maintains the inactive state of αMβ2 integrin in vivo and thereby regulates leukocyte adhesion to integrin ligands under flow. Our findings offer a global view on cytoplasmic proteins interacting with different integrins and provide evidence for the existence of conformation-specific integrin interactors.
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Affiliation(s)
- Hui-Yuan Tseng
- Department of Molecular Medicine, Max Planck Institute for Biochemistry, 82152 Martinsried, Germany
| | - Anna V Samarelli
- Department of Molecular Medicine, Max Planck Institute for Biochemistry, 82152 Martinsried, Germany
| | - Patricia Kammerer
- Department of Molecular Medicine, Max Planck Institute for Biochemistry, 82152 Martinsried, Germany
| | - Sarah Scholze
- Department of Molecular Medicine, Max Planck Institute for Biochemistry, 82152 Martinsried, Germany
| | - Tilman Ziegler
- Department of Molecular Medicine, Max Planck Institute for Biochemistry, 82152 Martinsried, Germany
| | - Roland Immler
- Walter Brendel Center for Experimental Medicine, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Roy Zent
- Division of Nephrology, Department of Medicine, Vanderbilt University, Nashville, 37232 Tennessee, USA.,Department of Medicine, Veterans Affairs Medical Center, Nashville, 37232 Tennessee, USA
| | - Markus Sperandio
- Walter Brendel Center for Experimental Medicine, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Charles R Sanders
- Department of Biochemistry, Center for Structural Biology, and Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, 37232 Tennessee, USA
| | - Reinhard Fässler
- Department of Molecular Medicine, Max Planck Institute for Biochemistry, 82152 Martinsried, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, 80802 Munich, Germany
| | - Ralph T Böttcher
- Department of Molecular Medicine, Max Planck Institute for Biochemistry, 82152 Martinsried, Germany .,DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, 80802 Munich, Germany
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40
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Lacy MM, Ma R, Ravindra NG, Berro J. Molecular mechanisms of force production in clathrin-mediated endocytosis. FEBS Lett 2018; 592:3586-3605. [PMID: 30006986 PMCID: PMC6231980 DOI: 10.1002/1873-3468.13192] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 06/21/2018] [Accepted: 07/12/2018] [Indexed: 01/21/2023]
Abstract
During clathrin-mediated endocytosis (CME), a flat patch of membrane is invaginated and pinched off to release a vesicle into the cytoplasm. In yeast CME, over 60 proteins-including a dynamic actin meshwork-self-assemble to deform the plasma membrane. Several models have been proposed for how actin and other molecules produce the forces necessary to overcome the mechanical barriers of membrane tension and turgor pressure, but the precise mechanisms and a full picture of their interplay are still not clear. In this review, we discuss the evidence for these force production models from a quantitative perspective and propose future directions for experimental and theoretical work that could clarify their various contributions.
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Affiliation(s)
- Michael M Lacy
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Nanobiology Institute, Yale University, West Haven, CT, USA
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT, USA
| | - Rui Ma
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Nanobiology Institute, Yale University, West Haven, CT, USA
| | - Neal G Ravindra
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Nanobiology Institute, Yale University, West Haven, CT, USA
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT, USA
| | - Julien Berro
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Nanobiology Institute, Yale University, West Haven, CT, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
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41
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Schön M, Mey I, Steinem C. Influence of cross-linkers on ezrin-bound minimal actin cortices. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 144:91-101. [PMID: 30093083 DOI: 10.1016/j.pbiomolbio.2018.07.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/13/2018] [Accepted: 07/31/2018] [Indexed: 12/21/2022]
Abstract
The actin cortex is a thin network coupled to the plasma membrane of cells, responsible for e.g., cell shape, motility, growth and division. Several model systems for minimal actin cortices (MACs) have been discussed in literature trying to mimic the complex interplay of membrane and actin. We recapitulate on different types of MACs using either three dimensional droplet interfaces or lipid bilayers to which F-actin networks are attached to or planar lipid bilayers with bound actin networks. Binding of the network to the membrane interface significantly influences its properties as well as its dynamics. This in turn also influences, how cross-linkers as well as myosin motors act on the network. Here, we describe the coupling of a filamentous actin network to a model membrane via the protein ezrin, a member of the ezrin-radixin-moesin family, which forms a direct linkage between the plasma membrane and the cortical web. Ezrin binding to the membrane is achieved by the lipid PtdIns(4,5)P2, while attachment to F-actin is mediated via the C-terminal domain of the protein leading to a two dimensional arrangement of actin filaments on the membrane. Addition of cross-linkers such as fascin and α-actinin influences the architecture of the actin network, which we have investigated by means of fluorescence microscopy. The results are discussed in terms of the dynamics of the filaments on the membrane surface.
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Affiliation(s)
- Markus Schön
- Georg-August Universität Göttingen, Institut für Organische und Biomolekulare Chemie, Tammannstr. 2, 37077, Göttingen, Germany
| | - Ingo Mey
- Georg-August Universität Göttingen, Institut für Organische und Biomolekulare Chemie, Tammannstr. 2, 37077, Göttingen, Germany.
| | - Claudia Steinem
- Georg-August Universität Göttingen, Institut für Organische und Biomolekulare Chemie, Tammannstr. 2, 37077, Göttingen, Germany.
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42
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Mund M, van der Beek JA, Deschamps J, Dmitrieff S, Hoess P, Monster JL, Picco A, Nédélec F, Kaksonen M, Ries J. Systematic Nanoscale Analysis of Endocytosis Links Efficient Vesicle Formation to Patterned Actin Nucleation. Cell 2018; 174:884-896.e17. [PMID: 30057119 PMCID: PMC6086932 DOI: 10.1016/j.cell.2018.06.032] [Citation(s) in RCA: 122] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 02/27/2018] [Accepted: 06/13/2018] [Indexed: 11/18/2022]
Abstract
Clathrin-mediated endocytosis is an essential cellular function in all eukaryotes that is driven by a self-assembled macromolecular machine of over 50 different proteins in tens to hundreds of copies. How these proteins are organized to produce endocytic vesicles with high precision and efficiency is not understood. Here, we developed high-throughput superresolution microscopy to reconstruct the nanoscale structural organization of 23 endocytic proteins from over 100,000 endocytic sites in yeast. We found that proteins assemble by radially ordered recruitment according to function. WASP family proteins form a circular nanoscale template on the membrane to spatially control actin nucleation during vesicle formation. Mathematical modeling of actin polymerization showed that this WASP nano-template optimizes force generation for membrane invagination and substantially increases the efficiency of endocytosis. Such nanoscale pre-patterning of actin nucleation may represent a general design principle for directional force generation in membrane remodeling processes such as during cell migration and division.
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Affiliation(s)
- Markus Mund
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Johannes Albertus van der Beek
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Joran Deschamps
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Serge Dmitrieff
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Philipp Hoess
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany; Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences
| | - Jooske Louise Monster
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Andrea Picco
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
| | - François Nédélec
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Marko Kaksonen
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva, Switzerland
| | - Jonas Ries
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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43
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Ma R, Berro J. Structural organization and energy storage in crosslinked actin assemblies. PLoS Comput Biol 2018; 14:e1006150. [PMID: 29813051 PMCID: PMC5993335 DOI: 10.1371/journal.pcbi.1006150] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 06/08/2018] [Accepted: 04/18/2018] [Indexed: 11/19/2022] Open
Abstract
During clathrin-mediated endocytosis in yeast cells, short actin filaments (< 200nm) and crosslinking protein fimbrin assemble to drive the internalization of the plasma membrane. However, the organization of the actin meshwork during endocytosis remains largely unknown. In addition, only a small fraction of the force necessary to elongate and pinch off vesicles can be accounted for by actin polymerization alone. In this paper, we used mathematical modeling to study the self-organization of rigid actin filaments in the presence of elastic crosslinkers in conditions relevant to endocytosis. We found that actin filaments condense into either a disordered meshwork or an ordered bundle depending on filament length and the mechanical and kinetic properties of the crosslinkers. Our simulations also demonstrated that these nanometer-scale actin structures can store a large amount of elastic energy within the crosslinkers (up to 10kBT per crosslinker). This conversion of binding energy into elastic energy is the consequence of geometric constraints created by the helical pitch of the actin filaments, which results in frustrated configurations of crosslinkers attached to filaments. We propose that this stored elastic energy can be used at a later time in the endocytic process. As a proof of principle, we presented a simple mechanism for sustained torque production by ordered detachment of crosslinkers from a pair of parallel filaments.
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Affiliation(s)
- Rui Ma
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
- Nanobiology Institute, Yale University, West Haven, Connecticut, United States of America
| | - Julien Berro
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
- Nanobiology Institute, Yale University, West Haven, Connecticut, United States of America
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, United States of America
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44
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Preisner H, Habicht J, Garg SG, Gould SB. Intermediate filament protein evolution and protists. Cytoskeleton (Hoboken) 2018; 75:231-243. [PMID: 29573204 DOI: 10.1002/cm.21443] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/02/2018] [Accepted: 03/12/2018] [Indexed: 01/20/2023]
Abstract
Metazoans evolved from a single protist lineage. While all eukaryotes share a conserved actin and tubulin-based cytoskeleton, it is commonly perceived that intermediate filaments (IFs), including lamin, vimentin or keratin among many others, are restricted to metazoans. Actin and tubulin proteins are conserved enough to be detectable across all eukaryotic genomes using standard phylogenetic methods, but IF proteins, in contrast, are notoriously difficult to identify by such means. Since the 1950s, dozens of cytoskeletal proteins in protists have been identified that seemingly do not belong to any of the IF families described for metazoans, yet, from a structural and functional perspective fit criteria that define metazoan IF proteins. Here, we briefly review IF protein discovery in metazoans and the implications this had for the definition of this protein family. We argue that the many cytoskeletal and filament-forming proteins of protists should be incorporated into a more comprehensive picture of IF evolution by aligning it with the recent identification of lamins across the phylogenetic diversity of eukaryotic supergroups. This then brings forth the question of how the diversity of IF proteins has unfolded. The evolution of IF proteins likely represents an example of convergent evolution, which, in combination with the speed with which these cytoskeletal proteins are evolving, generated their current diversity. IF proteins did not first emerge in metazoa, but in protists. Only the emergence of cytosolic IF proteins that appear to stem from a nuclear lamin is unique to animals and coincided with the emergence of true animal multicellularity.
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Affiliation(s)
- Harald Preisner
- Institute for Molecular Evolution, Heinrich-Heine-University, Düsseldorf, Germany
| | - Jörn Habicht
- Institute for Molecular Evolution, Heinrich-Heine-University, Düsseldorf, Germany
| | - Sriram G Garg
- Institute for Molecular Evolution, Heinrich-Heine-University, Düsseldorf, Germany
| | - Sven B Gould
- Institute for Molecular Evolution, Heinrich-Heine-University, Düsseldorf, Germany
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45
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Picco A, Kukulski W, Manenschijn HE, Specht T, Briggs JAG, Kaksonen M. The contributions of the actin machinery to endocytic membrane bending and vesicle formation. Mol Biol Cell 2018; 29:1346-1358. [PMID: 29851558 PMCID: PMC5994895 DOI: 10.1091/mbc.e17-11-0688] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Branched and cross-linked actin networks mediate cellular processes that move and shape membranes. To understand how actin contributes during the different stages of endocytic membrane reshaping, we analyzed deletion mutants of yeast actin network components using a hybrid imaging approach that combines live imaging with correlative microscopy. We could thus temporally dissect the effects of different actin network perturbations, revealing distinct stages of actin-based membrane reshaping. Our data show that initiation of membrane bending requires the actin network to be physically linked to the plasma membrane and to be optimally cross-linked. Once initiated, the membrane invagination process is driven by nucleation and polymerization of new actin filaments, independent of the degree of cross-linking and unaffected by a surplus of actin network components. A key transition occurs 2 s before scission, when the filament nucleation rate drops. From that time point on, invagination growth and vesicle scission are driven by an expansion of the actin network without a proportional increase of net actin amounts. The expansion is sensitive to the amount of filamentous actin and its cross-linking. Our results suggest that the mechanism by which actin reshapes the membrane changes during the progress of endocytosis, possibly adapting to varying force requirements.
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Affiliation(s)
- Andrea Picco
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Wanda Kukulski
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Hetty E Manenschijn
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, 1211 Geneva, Switzerland.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Tanja Specht
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - John A G Briggs
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Marko Kaksonen
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, 1211 Geneva, Switzerland
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46
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Nguyen LT, Swulius MT, Aich S, Mishra M, Jensen GJ. Coarse-grained simulations of actomyosin rings point to a nodeless model involving both unipolar and bipolar myosins. Mol Biol Cell 2018; 29:1318-1331. [PMID: 29851561 PMCID: PMC5994903 DOI: 10.1091/mbc.e17-12-0736] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cytokinesis in many eukaryotic cells is orchestrated by a contractile actomyosin ring. While many of the proteins involved are known, the mechanism of constriction remains unclear. Informed by the existing literature and new three-dimensional (3D) molecular details from electron cryotomography, here we develop 3D coarse-grained models of actin filaments, unipolar and bipolar myosins, actin cross-linkers, and membranes and simulate their interactions. Assuming that local force on the membrane results in inward growth of the cell wall, we explored a matrix of possible actomyosin configurations and found that node-based architectures like those presently described for ring assembly result in membrane puckers not seen in electron microscope images of real cells. Instead, the model that best matches data from fluorescence microscopy, electron cryotomography, and biochemical experiments is one in which actin filaments transmit force to the membrane through evenly distributed, membrane-attached, unipolar myosins, with bipolar myosins in the ring driving contraction. While at this point this model is only favored (not proven), the work highlights the power of coarse-grained biophysical simulations to compare complex mechanistic hypotheses.
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Affiliation(s)
- Lam T Nguyen
- California Institute of Technology, Pasadena, CA 91125.,Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - Matthew T Swulius
- California Institute of Technology, Pasadena, CA 91125.,Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - Samya Aich
- Tata Institute of Fundamental Research, Mumbai 400005, India
| | | | - Grant J Jensen
- California Institute of Technology, Pasadena, CA 91125.,Howard Hughes Medical Institute, Chevy Chase, MD 20815
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47
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Rajagopal V, Holmes WR, Lee PVS. Computational modeling of single-cell mechanics and cytoskeletal mechanobiology. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2018; 10:e1407. [PMID: 29195023 PMCID: PMC5836888 DOI: 10.1002/wsbm.1407] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 08/19/2017] [Accepted: 09/07/2017] [Indexed: 01/10/2023]
Abstract
Cellular cytoskeletal mechanics plays a major role in many aspects of human health from organ development to wound healing, tissue homeostasis and cancer metastasis. We summarize the state-of-the-art techniques for mathematically modeling cellular stiffness and mechanics and the cytoskeletal components and factors that regulate them. We highlight key experiments that have assisted model parameterization and compare the advantages of different models that have been used to recapitulate these experiments. An overview of feed-forward mechanisms from signaling to cytoskeleton remodeling is provided, followed by a discussion of the rapidly growing niche of encapsulating feedback mechanisms from cytoskeletal and cell mechanics to signaling. We discuss broad areas of advancement that could accelerate research and understanding of cellular mechanobiology. A precise understanding of the molecular mechanisms that affect cell and tissue mechanics and function will underpin innovations in medical device technologies of the future. WIREs Syst Biol Med 2018, 10:e1407. doi: 10.1002/wsbm.1407 This article is categorized under: Models of Systems Properties and Processes > Mechanistic Models Physiology > Mammalian Physiology in Health and Disease Models of Systems Properties and Processes > Cellular Models.
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Affiliation(s)
- Vijay Rajagopal
- Cell Structure and Mechanobiology Group, Department of Biomedical EngineeringUniversity of MelbourneMelbourneAustralia
| | - William R. Holmes
- Department of Physics and AstronomyVanderbilt UniversityNashvilleTNUSA
| | - Peter Vee Sin Lee
- Cell and Tissue Biomechanics Laboratory, Department of Biomedical EngineeringUniversity of MelbourneMelbourneAustralia
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48
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Morita R, Takaine M, Numata O, Nakano K. Molecular dissection of the actin-binding ability of the fission yeast α-actinin, Ain1, in vitro and in vivo. J Biochem 2017; 162:93-102. [PMID: 28338873 DOI: 10.1093/jb/mvx008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 12/27/2016] [Indexed: 02/02/2023] Open
Abstract
A contractile ring (CR) is involved in cytokinesis in animal and yeast cells. Although several types of actin-bundling proteins associate with F-actin in the CR, their individual roles in the CR have not yet been elucidated in detail. Ain1 is the sole α-actinin homologue in the fission yeast Schizosaccharomyces pombe and specifically localizes to the CR with a high turnover rate. S. pombe cells lacking the ain1+ gene show defects in cytokinesis under stress conditions. We herein investigated the biochemical activity and cellular localization mechanisms of Ain1. Ain1 showed weaker affinity to F-actin in vitro than other actin-bundling proteins in S. pombe. We identified a mutation that presumably loosened the interaction between two calponin-homology domains constituting the single actin-binding domain (ABD) of Ain1, which strengthened the actin-binding activity of Ain1. This mutant protein induced a deformation in the ring shape of the CR. Neither a truncated protein consisting only of an N-terminal ABD nor a truncated protein lacking a C-terminal region containing an EF-hand motif localized to the CR, whereas the latter was involved in the bundling of F-actin in vitro. We herein propose detailed mechanisms for how each part of the molecule is involved in the proper cellular localization and function of Ain1.
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Affiliation(s)
- Rikuri Morita
- Department of Biological Sciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennohdai, Tsukuba, Ibaraki 305-8572, Japan
| | - Masak Takaine
- Department of Biological Sciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennohdai, Tsukuba, Ibaraki 305-8572, Japan
| | - Osamu Numata
- Department of Biological Sciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennohdai, Tsukuba, Ibaraki 305-8572, Japan
| | - Kentaro Nakano
- Department of Biological Sciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennohdai, Tsukuba, Ibaraki 305-8572, Japan
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49
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Wottawa M, Naas S, Böttger J, van Belle GJ, Möbius W, Revelo NH, Heidenreich D, von Ahlen M, Zieseniss A, Kröhnert K, Lutz S, Lenz C, Urlaub H, Rizzoli SO, Katschinski DM. Hypoxia-stimulated membrane trafficking requires T-plastin. Acta Physiol (Oxf) 2017; 221:59-73. [PMID: 28218996 DOI: 10.1111/apha.12859] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 01/25/2017] [Accepted: 02/15/2017] [Indexed: 12/30/2022]
Abstract
AIM Traffic between the plasma membrane and the endomembrane compartments is an essential feature of eukaryotic cells. The secretory pathway sends cargoes from biosynthetic compartments to the plasma membrane. This is counterbalanced by a retrograde endocytic route and is essential for cell homoeostasis. Cells need to adapt rapidly to environmental challenges such as the reduction of pO2 which, however, has not been analysed in relation to membrane trafficking in detail. Therefore, we determined changes in the plasma membrane trafficking in normoxia, hypoxia, and after reoxygenation. METHODS Membrane trafficking was analysed by using the bulk membrane endocytosis marker FM 1-43, the newly developed membrane probe mCLING, wheat germ agglutinin as well as fluorescently labelled cholera toxin subunit B. Additionally, the uptake of specific membrane proteins was determined. In parallel, a non-biased SILAC screen was performed to analyse the abundance of membrane proteins in normoxia and hypoxia. RESULTS Membrane trafficking was increased in hypoxia and quickly reversed upon reoxygenation. This effect was independent of the hypoxia-inducible factor (HIF) system. Using SILAC technology, we identified that the actin-bundling protein T-plastin is recruited to the plasma membrane in hypoxia. By the use of T-plastin knockdown cells, we could show that T-plastin mediates the hypoxia-induced membrane trafficking, which was associated with an increased actin density in the cells as determined by electron microscopy. CONCLUSION Membrane trafficking is highly dynamic upon hypoxia. This phenotype is quickly reversible upon reoxygenation, which suggests that this mechanism participates in the cellular adaptation to hypoxia.
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Affiliation(s)
- M. Wottawa
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - S. Naas
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - J. Böttger
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - G. J. van Belle
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - W. Möbius
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB); Göttingen Germany
| | - N. H. Revelo
- Institute of Neuro- and Sensory Physiology; UMG, CNMPB; Göttingen Germany
| | - D. Heidenreich
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - M. von Ahlen
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - A. Zieseniss
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
| | - K. Kröhnert
- Institute of Neuro- and Sensory Physiology; UMG, CNMPB; Göttingen Germany
| | - S. Lutz
- Institute of Pharmacology; UMG; Göttingen Germany
| | - C. Lenz
- Bioanalytical Mass Spectrometry; Max Planck Institute for Biophysical Chemistry; Göttingen Germany
- Bioanalytics Research Group; Institute of Clinical Chemistry; UMG; Göttingen Germany
| | - H. Urlaub
- Bioanalytical Mass Spectrometry; Max Planck Institute for Biophysical Chemistry; Göttingen Germany
- Bioanalytics Research Group; Institute of Clinical Chemistry; UMG; Göttingen Germany
| | - S. O. Rizzoli
- Institute of Neuro- and Sensory Physiology; UMG, CNMPB; Göttingen Germany
| | - D. M. Katschinski
- Institute of Cardiovascular Physiology; University Medical Center Göttingen (UMG); Göttingen Germany
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50
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Alvarado J, Sheinman M, Sharma A, MacKintosh FC, Koenderink GH. Force percolation of contractile active gels. SOFT MATTER 2017; 13:5624-5644. [PMID: 28812094 DOI: 10.1039/c7sm00834a] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Living systems provide a paradigmatic example of active soft matter. Cells and tissues comprise viscoelastic materials that exert forces and can actively change shape. This strikingly autonomous behavior is powered by the cytoskeleton, an active gel of semiflexible filaments, crosslinks, and molecular motors inside cells. Although individual motors are only a few nm in size and exert minute forces of a few pN, cells spatially integrate the activity of an ensemble of motors to produce larger contractile forces (∼nN and greater) on cellular, tissue, and organismal length scales. Here we review experimental and theoretical studies on contractile active gels composed of actin filaments and myosin motors. Unlike other active soft matter systems, which tend to form ordered patterns, actin-myosin systems exhibit a generic tendency to contract. Experimental studies of reconstituted actin-myosin model systems have long suggested that a mechanical interplay between motor activity and the network's connectivity governs this contractile behavior. Recent theoretical models indicate that this interplay can be understood in terms of percolation models, extended to include effects of motor activity on the network connectivity. Based on concepts from percolation theory, we propose a state diagram that unites a large body of experimental observations. This framework provides valuable insights into the mechanisms that drive cellular shape changes and also provides design principles for synthetic active materials.
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Affiliation(s)
- José Alvarado
- Systems Biophysics Department, AMOLF, 1098 XG Amsterdam, The Netherlands.
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