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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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2
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Wang X, Luo Y, He S, Lu Y, Gong Y, Gao L, Mao S, Liu X, Jiang N, Pu Q, Du D, Shu Y, Hai S, Li S, Chen HN, Zhao Y, Xie D, Qi S, Lei P, Hu H, Xu H, Zhou ZG, Dong B, Zhang H, Zhang Y, Dai L. Age-, sex- and proximal-distal-resolved multi-omics identifies regulators of intestinal aging in non-human primates. NATURE AGING 2024; 4:414-433. [PMID: 38321225 PMCID: PMC10950786 DOI: 10.1038/s43587-024-00572-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 01/08/2024] [Indexed: 02/08/2024]
Abstract
The incidence of intestinal diseases increases with age, yet the mechanisms governing gut aging and its link to diseases, such as colorectal cancer (CRC), remain elusive. In this study, while considering age, sex and proximal-distal variations, we used a multi-omics approach in non-human primates (Macaca fascicularis) to shed light on the heterogeneity of intestinal aging and identify potential regulators of gut aging. We explored the roles of several regulators, including those from tryptophan metabolism, in intestinal function and lifespan in Caenorhabditis elegans. Suggesting conservation of region specificity, tryptophan metabolism via the kynurenine and serotonin (5-HT) pathways varied between the proximal and distal colon, and, using a mouse colitis model, we observed that distal colitis was more sensitive to 5-HT treatment. Additionally, using proteomics analysis of human CRC samples, we identified links between gut aging and CRC, with high HPX levels predicting poor prognosis in older patients with CRC. Together, this work provides potential targets for preventing gut aging and associated diseases.
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Grants
- P40 OD010440 NIH HHS
- National Natural Science Foundation of China (National Science Foundation of China)
- National Key R&D Program of China,2022YFA1303200, 2018YFC2000305; The 135 Project of West China Hospital, ZYJC21005, ZYGD20010 and ZYYC23013.
- Natural Science Foundation of Sichuan Province,2023NSFSC1196
- Natural Science Foundation of Sichuan Province,2021YFS0134
- National Clinical Research Center for Geriatrics of West China Hospital, Z2021JC005
- The 135 Project of West China Hospital, ZYYC23025.
- National Key R&D Program of China, 2019YFA0110203;
- National Clinical Research Center for Geriatrics of West China Hospital, Z2021JC006;
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Affiliation(s)
- Xinyuan Wang
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
- Advanced Mass Spectrometry Center, Research Core Facility, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Yaru Luo
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Siyu He
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Ying Lu
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Yanqiu Gong
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Li Gao
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Shengqiang Mao
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaohui Liu
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Na Jiang
- Advanced Mass Spectrometry Center, Research Core Facility, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Qianlun Pu
- Advanced Mass Spectrometry Center, Research Core Facility, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Dan Du
- Advanced Mass Spectrometry Center, Research Core Facility, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Yang Shu
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Shan Hai
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Shuangqing Li
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Hai-Ning Chen
- Colorectal Cancer Center, Department of General Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Yi Zhao
- Department of Rheumatology and Immunology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Dan Xie
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Shiqian Qi
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Peng Lei
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Hongbo Hu
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Heng Xu
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Zong-Guang Zhou
- Colorectal Cancer Center, Department of General Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Biao Dong
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.
| | - Huiyuan Zhang
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.
| | - Yan Zhang
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.
| | - Lunzhi Dai
- National Clinical Research Center for Geriatrics, Center for Immunology and Hematology and General Practice Ward/International Medical Center Ward, General Practice Medical Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.
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3
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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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4
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Yuan G, Gao H, Yang T. Exploring the Role of the Plant Actin Cytoskeleton: From Signaling to Cellular Functions. Int J Mol Sci 2023; 24:15480. [PMID: 37895158 PMCID: PMC10607326 DOI: 10.3390/ijms242015480] [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: 08/29/2023] [Revised: 10/06/2023] [Accepted: 10/21/2023] [Indexed: 10/29/2023] Open
Abstract
The plant actin cytoskeleton is characterized by the basic properties of dynamic array, which plays a central role in numerous conserved processes that are required for diverse cellular functions. Here, we focus on how actins and actin-related proteins (ARPs), which represent two classical branches of a greatly diverse superfamily of ATPases, are involved in fundamental functions underlying signal regulation of plant growth and development. Moreover, we review the structure, assembly dynamics, and biological functions of filamentous actin (F-actin) from a molecular perspective. The various accessory proteins known as actin-binding proteins (ABPs) partner with F-actin to finely tune actin dynamics, often in response to various cell signaling pathways. Our understanding of the significance of the actin cytoskeleton in vital cellular activities has been furthered by comparison of conserved functions of actin filaments across different species combined with advanced microscopic techniques and experimental methods. We discuss the current model of the plant actin cytoskeleton, followed by examples of the signaling mechanisms under the supervision of F-actin related to cell morphogenesis, polar growth, and cytoplasmic streaming. Determination of the theoretical basis of how the cytoskeleton works is important in itself and is beneficial to future applications aimed at improving crop biomass and production efficiency.
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Affiliation(s)
| | | | - Tao Yang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China; (G.Y.); (H.G.)
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5
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Guo S, Hoeprich GJ, Magliozzi JO, Gelles J, Goode BL. Dynamic remodeling of actin networks by cyclase-associated protein and CAP-Abp1 complexes. Curr Biol 2023; 33:4484-4495.e5. [PMID: 37797614 DOI: 10.1016/j.cub.2023.09.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 07/20/2023] [Accepted: 09/13/2023] [Indexed: 10/07/2023]
Abstract
How actin filaments are spatially organized and remodeled into diverse higher-order networks in vivo is still not well understood. Here, we report an unexpected F-actin "coalescence" activity driven by cyclase-associated protein (CAP) and enhanced by its interactions with actin-binding protein 1 (Abp1). We directly observe S. cerevisiae CAP and Abp1 rapidly transforming branched or linear actin networks by bundling and sliding filaments past each other, maximizing filament overlap, and promoting compaction into bundles. This activity does not require ATP and is conserved, as similar behaviors are observed for the mammalian homologs of CAP and Abp1. Coalescence depends on the CAP oligomerization domain but not the helical folded domain (HFD) that mediates its functions in F-actin severing and depolymerization. Coalescence by CAP-Abp1 further depends on interactions between CAP and Abp1 and interactions between Abp1 and F-actin. Our results are consistent with a mechanism in which the formation of energetically favorable sliding CAP and CAP-Abp1 crosslinks drives F-actin bundle compaction. Roles for CAP and CAP-Abp1 in actin remodeling in vivo are supported by strong phenotypes arising from deletion of the CAP oligomerization domain and by genetic interactions between sac6Δ and an srv2-301 mutant that does not bind Abp1. Together, these observations identify a new actin filament remodeling function for CAP, which is further enhanced by its direct interactions with Abp1.
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Affiliation(s)
- Siyang Guo
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - Gregory J Hoeprich
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - Joseph O Magliozzi
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - Jeff Gelles
- Department of Biochemistry, Brandeis University, 415 South Street, Waltham, MA 02454, USA.
| | - Bruce L Goode
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA.
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6
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Stephan OOH. Effects of environmental stress factors on the actin cytoskeleton of fungi and plants: Ionizing radiation and ROS. Cytoskeleton (Hoboken) 2023; 80:330-355. [PMID: 37066976 DOI: 10.1002/cm.21758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/20/2023] [Accepted: 03/29/2023] [Indexed: 04/18/2023]
Abstract
Actin is an abundant and multifaceted protein in eukaryotic cells that has been detected in the cytoplasm as well as in the nucleus. In cooperation with numerous interacting accessory-proteins, monomeric actin (G-actin) polymerizes into microfilaments (F-actin) which constitute ubiquitous subcellular higher order structures. Considering the extensive spatial dimensions and multifunctionality of actin superarrays, the present study analyses the issue if and to what extent environmental stress factors, specifically ionizing radiation (IR) and reactive oxygen species (ROS), affect the cellular actin-entity. In that context, this review particularly surveys IR-response of fungi and plants. It examines in detail which actin-related cellular constituents and molecular pathways are influenced by IR and related ROS. This comprehensive survey concludes that the general integrity of the total cellular actin cytoskeleton is a requirement for IR-tolerance. Actin's functions in genome organization and nuclear events like chromatin remodeling, DNA-repair, and transcription play a key role. Beyond that, it is highly significant that the macromolecular cytoplasmic and cortical actin-frameworks are affected by IR as well. In response to IR, actin-filament bundling proteins (fimbrins) are required to stabilize cables or patches. In addition, the actin-associated factors mediating cellular polarity are essential for IR-survivability. Moreover, it is concluded that a cellular homeostasis system comprising ROS, ROS-scavengers, NADPH-oxidases, and the actin cytoskeleton plays an essential role here. Consequently, besides the actin-fraction which controls crucial genome-integrity, also the portion which facilitates orderly cellular transport and polarized growth has to be maintained in order to survive IR.
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Affiliation(s)
- Octavian O H Stephan
- Department of Biology, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Bavaria, 91058, Germany
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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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Chen J, Li M, Liu Y, Guan T, Yang X, Wen Y, Zhu Y, Xiao Z, Shen X, Zhang H, Tang H, Liu T. PIN1 and CDK1 cooperatively govern pVHL stability and suppressive functions. Cell Death Differ 2023; 30:1082-1095. [PMID: 36813923 PMCID: PMC10070344 DOI: 10.1038/s41418-023-01128-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/20/2023] [Accepted: 02/01/2023] [Indexed: 02/24/2023] Open
Abstract
The VHL protein (pVHL) functions as a tumor suppressor by regulating the degradation or activation of protein substrates such as HIF1α and Akt. In human cancers harboring wild-type VHL, the aberrant downregulation of pVHL is frequently detected and critically contributes to tumor progression. However, the underlying mechanism by which the stability of pVHL is deregulated in these cancers remains elusive. Here, we identify cyclin-dependent kinase 1 (CDK1) and peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (PIN1) as two previously uncharacterized regulators of pVHL in multiple types of human cancers harboring wild-type VHL including triple-negative breast cancer (TNBC). PIN1 and CDK1 cooperatively modulate the protein turnover of pVHL, thereby conferring tumor growth, chemotherapeutic resistance and metastasis both in vitro and in vivo. Mechanistically, CDK1 directly phosphorylates pVHL at Ser80, which primes the recognition of pVHL by PIN1. PIN1 then binds to phosphorylated pVHL and facilitates the recruitment of the E3 ligase WSB1, therefore targeting pVHL for ubiquitination and degradation. Furthermore, the genetic ablation or pharmacological inhibition of CDK1 by RO-3306 and PIN1 by all-trans retinoic acid (ATRA), the standard care for Acute Promyelocytic Leukemia could markedly suppress tumor growth, metastasis and sensitize cancer cells to chemotherapeutic drugs in a pVHL dependent manner. The histological analyses show that PIN1 and CDK1 are highly expressed in TNBC samples, which negatively correlate with the expression of pVHL. Taken together, our findings reveal the previous unrecognized tumor-promoting function of CDK1/PIN1 axis through destabilizing pVHL and provide the preclinical evidence that targeting CDK1/PIN1 is an appealing strategy in the treatment of multiple cancers with wild-type VHL.
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Affiliation(s)
- Jiayi Chen
- College of Pharmacy/International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Ministry of Education (MOE) of China, Jinan University, Guangzhou, 510632, P. R. China
| | - Mei Li
- College of Pharmacy/International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Ministry of Education (MOE) of China, Jinan University, Guangzhou, 510632, P. R. China
| | - Yeqing Liu
- Department of Pathology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, 510120, P. R. China
| | - Tangming Guan
- College of Pharmacy/International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Ministry of Education (MOE) of China, Jinan University, Guangzhou, 510632, P. R. China
| | - Xiao Yang
- College of Pharmacy/International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Ministry of Education (MOE) of China, Jinan University, Guangzhou, 510632, P. R. China
| | - Yalei Wen
- College of Pharmacy/International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Ministry of Education (MOE) of China, Jinan University, Guangzhou, 510632, P. R. China
| | - Yingjie Zhu
- College of Pharmacy/International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Ministry of Education (MOE) of China, Jinan University, Guangzhou, 510632, P. R. China
| | - Zeyu Xiao
- The Guangzhou Key Laboratory of Molecular and Functional Imaging for Clinical Translation, The First Affiliated Hospital of Jinan University, Guangzhou, 510632, P. R. China
| | - Xiangchun Shen
- The State Key Laboratory of Functions and Applications of Medicinal Plants, School of Pharmaceutic Sciences, Guizhou Medical University, University Town, Guiyang City and Guian New District, Guiyang, 550025, P. R. China
| | - Haoxing Zhang
- Guangdong Provincial Key Laboratory of Genome Stability and Disease Prevention, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518055, P. R. China.
| | - Hui Tang
- Department of Central Laboratory, The First Affiliated Hospital of Jinan University, 510632, Guangzhou, P. R. China. .,Department of Clinical Laboratory, The Fifth Affiliated Hospital of Jinan University Heyuan Shenhe People's Hospital, Heyuan, 517000, P. R. China.
| | - Tongzheng Liu
- College of Pharmacy/International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Ministry of Education (MOE) of China, Jinan University, Guangzhou, 510632, P. R. China. .,The State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, P. R. China.
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9
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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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10
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Sherer LA, Courtemanche N. Cooperative bundling by fascin generates actin structures with architectures that depend on filament length. Front Cell Dev Biol 2022; 10:974047. [PMID: 36120572 PMCID: PMC9479110 DOI: 10.3389/fcell.2022.974047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/12/2022] [Indexed: 11/30/2022] Open
Abstract
The assembly of actin-based structures with precisely defined architectures supports essential cellular functions, including motility, intracellular transport, and division. The geometric arrangements of the filaments within actin structures are stabilized via the association of crosslinking proteins, which bind two filaments simultaneously. Because actin polymerization and crosslinking occur concurrently within the dynamic environment of the cell, these processes likely play interdependent roles in shaping the architectures of actin-based structures. To dissect the contribution of polymerization to the construction of higher-order actin structures, we investigated how filament elongation affects the formation of simple, polarized actin bundles by the crosslinking protein fascin. Using populations of actin filaments to represent distinct stages of elongation, we found that the rate of bundle assembly increases with filament length. Fascin assembles short filaments into discrete bundles, whereas bundles of long filaments merge with one another to form interconnected networks. Although filament elongation promotes bundle coalescence, many connections formed between elongating bundles are short-lived and are followed by filament breakage. Our data suggest that initiation of crosslinking early in elongation aligns growing filaments, creating a template for continued bundle assembly as elongation proceeds. This initial alignment promotes the assembly of bundles that are resistant to large changes in curvature that are required for coalescence into interconnected networks. As a result, bundles of short filaments remain straighter and more topologically discrete as elongation proceeds than bundles assembled from long filaments. Thus, uncoordinated filament elongation and crosslinking can alter the architecture of bundled actin networks, highlighting the importance of maintaining precise control over filament length during the assembly of specialized actin structures.
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11
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Xie Y, Zhou F, Ma Q, Lu L, Miao Y. A teamwork promotion of formin-mediated actin nucleation by Bud6 and Aip5 in Saccharomyces cerevisiae. Mol Biol Cell 2021; 33:ar19. [PMID: 34818061 PMCID: PMC9236144 DOI: 10.1091/mbc.e21-06-0285] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Actin nucleation is achieved by collaborative teamwork of actin nucleator factors (NFs) and nucleation-promoting factors (NPFs) into functional protein complexes. Selective inter- and intramolecular interactions between the nucleation complex constituents enable diverse modes of complex assembly in initiating actin polymerization on demand. Budding yeast has two formins, Bni1 and Bnr1, which are teamed up with different NPFs. However, the selective pairing between formin NFs and NPFs into the nucleation core for actin polymerization is not completely understood. By examining the functions and interactions of NPFs and NFs via biochemistry, genetics, and mathematical modeling approaches, we found that two NPFs, Aip5 and Bud6, showed joint teamwork effort with Bni1 and Bnr1, respectively, by interacting with the C-terminal intrinsically disordered region (IDR) of formin, in which two NPFs work together to promote formin-mediated actin nucleation. Although the C-terminal IDRs of Bni1 and Bnr1 are distinct in length, each formin IDR orchestrates the recruitment of Bud6 and Aip5 cooperatively by different positioning strategies to form a functional complex. Our study demonstrated the dynamic assembly of the actin nucleation complex by recruiting multiple partners in budding yeast, which may be a general feature for effective actin nucleation by formins.
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Affiliation(s)
- Ying Xie
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Feng Zhou
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Qianqian Ma
- 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
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12
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Kadzik RS, Homa KE, Kovar DR. F-Actin Cytoskeleton Network Self-Organization Through Competition and Cooperation. Annu Rev Cell Dev Biol 2021; 36:35-60. [PMID: 33021819 DOI: 10.1146/annurev-cellbio-032320-094706] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many fundamental cellular processes such as division, polarization, endocytosis, and motility require the assembly, maintenance, and disassembly of filamentous actin (F-actin) networks at specific locations and times within the cell. The particular function of each network is governed by F-actin organization, size, and density as well as by its dynamics. The distinct characteristics of different F-actin networks are determined through the coordinated actions of specific sets of actin-binding proteins (ABPs). Furthermore, a cell typically assembles and uses multiple F-actin networks simultaneously within a common cytoplasm, so these networks must self-organize from a common pool of shared globular actin (G-actin) monomers and overlapping sets of ABPs. Recent advances in multicolor imaging and analysis of ABPs and their associated F-actin networks in cells, as well as the development of sophisticated in vitro reconstitutions of networks with ensembles of ABPs, have allowed the field to start uncovering the underlying principles by which cells self-organize diverse F-actin networks to execute basic cellular functions.
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Affiliation(s)
- Rachel S Kadzik
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA; , .,Department of Molecular BioSciences, Northwestern University, Evanston, Illinois 60208, USA;
| | - Kaitlin E Homa
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA; ,
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA; , .,Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, USA
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13
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Xie Y, Miao Y. Polarisome assembly mediates actin remodeling during polarized yeast and fungal growth. J Cell Sci 2021; 134:134/1/jcs247916. [PMID: 33419950 DOI: 10.1242/jcs.247916] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Dynamic assembly and remodeling of actin is critical for many cellular processes during development and stress adaptation. In filamentous fungi and budding yeast, actin cables align in a polarized manner along the mother-to-daughter cell axis, and are essential for the establishment and maintenance of polarity; moreover, they rapidly remodel in response to environmental cues to achieve an optimal system response. A formin at the tip region within a macromolecular complex, called the polarisome, is responsible for driving actin cable polymerization during polarity establishment. This polarisome undergoes dynamic assembly through spatial and temporally regulated interactions between its components. Understanding this process is important to comprehend the tuneable activities of the formin-centered nucleation core, which are regulated through divergent molecular interactions and assembly modes within the polarisome. In this Review, we focus on how intrinsically disordered regions (IDRs) orchestrate the condensation of the polarisome components and the dynamic assembly of the complex. In addition, we address how these components are dynamically distributed in and out of the assembly zone, thereby regulating polarized growth. We also discuss the potential mechanical feedback mechanisms by which the force-induced actin polymerization at the tip of the budding yeast regulates the assembly and function of the polarisome.
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Affiliation(s)
- Ying Xie
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
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14
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Ma Z, Miao Y. Review: F-Actin remodelling during plant signal transduction via biomolecular assembly. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 301:110663. [PMID: 33218630 DOI: 10.1016/j.plantsci.2020.110663] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 06/11/2023]
Abstract
During signal transduction, multivalent interactions establish dynamic molecular connectivities that propagate molecular cascades throughout the entire signaling pathway. Such multivalent interactions include the initial activation, cascade signal transduction, and the amplification and assembly of structural machinery. For example, plants rapidly remodel the actin cytoskeleton during signal transduction by perceiving a wide range of mechanical and chemical cues from developmental and defense pathways. Actin treadmilling is stepwise-regulated by interactions between actin and actin-binding proteins (ABPs). Emerging evidence shows that intrinsically disordered regions (IDRs) enable flexible and promiscuous interactions that serve as the functional hub for generating cellular interactomes underlying various signaling events. Though IDRs are present in a majority of ABPs, few of the functional roles of IDR in the interaction and functions of ABPs have been defined. The distinct features of IDRs create diverse and dynamic molecular interactions that introduce a new paradigm to our understanding of the structure-function relationships for actin assembly. In this review, we will create a snapshot of recent advances in IDR-mediated plant actin remodeling and discuss future research directions in studying the complexity of actin assembly via multifaceted biomolecular assembly during signal transduction.
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Affiliation(s)
- Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore.
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15
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Xie Y, Loh ZY, Xue J, Zhou F, Sun J, Qiao Z, Jin S, Deng Y, Li H, Wang Y, Lu L, Gao Y, Miao Y. Orchestrated actin nucleation by the Candida albicans polarisome complex enables filamentous growth. J Biol Chem 2020; 295:14840-14854. [PMID: 32848016 DOI: 10.1074/jbc.ra120.013890] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/09/2020] [Indexed: 12/29/2022] Open
Abstract
Candida albicans is a dimorphic fungus that converts from a yeast form to a hyphae form during infection. This switch requires the formation of actin cable to coordinate polarized cell growth. It's known that nucleation of this cable requires a multiprotein complex localized at the tip called the polarisome, but the mechanisms underpinning this process were unclear. Here, we found that C. albicans Aip5, a homolog of polarisome component ScAip5 in Saccharomyces cerevisiae that nucleates actin polymerization and synergizes with the formin ScBni1, regulates actin assembly and hyphae growth synergistically with other polarisome proteins Bni1, Bud6, and Spa2. The C terminus of Aip5 binds directly to G-actin, Bni1, and the C-terminal of Bud6, which form the core of the nucleation complex to polymerize F-actin. Based on insights from structural biology and molecular dynamic simulations, we propose a possible complex conformation of the actin nucleation core, which provides cooperative positioning and supports the synergistic actin nucleation activity of a tri-protein complex Bni1-Bud6-Aip5. Together with known interactions of Bni1 with Bud6 and Aip5 in S. cerevisiae, our findings unravel molecular mechanisms of C. albicans by which the tri-protein complex coordinates the actin nucleation in actin cable assembly and hyphal growth, which is likely a conserved mechanism in different filamentous fungi and yeast.
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Affiliation(s)
- Ying Xie
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Zhi Yang Loh
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Jiao Xue
- School of Biological Sciences, Nanyang Technological University, Singapore; College of Life Science and Technology, Jinan University, Guangzhou, China; The College of Life Sciences, Northwest University, Xi'an, China
| | - Feng Zhou
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Jialin Sun
- School of Biological Sciences, Nanyang Technological University, Singapore; Institute of Molecular and Cell Biology, A*STAR, Singapore
| | - Zhu Qiao
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Shengyang Jin
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Yinyue Deng
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Guangzhou, China
| | - Hongye Li
- College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Yue Wang
- Institute of Molecular and Cell Biology, A*STAR, Singapore
| | - Lanyuan Lu
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Yonggui Gao
- School of Biological Sciences, Nanyang Technological University, Singapore; Institute of Molecular and Cell Biology, A*STAR, Singapore; NTU Institute of Structural Biology, Nanyang Technological University, Nanyang Drive, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore.
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16
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Dorweiler JE, Oddo MJ, Lyke DR, Reilly JA, Wisniewski BT, Davis EE, Kuborn AM, Merrill SJ, Manogaran AL. The actin cytoskeletal network plays a role in yeast prion transmission and contributes to prion stability. Mol Microbiol 2020; 114:480-494. [PMID: 32426863 DOI: 10.1111/mmi.14528] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 04/21/2020] [Accepted: 05/09/2020] [Indexed: 01/22/2023]
Abstract
Chaperone networks are required for the shearing and generation of transmissible propagons from pre-existing prion aggregates. However, other cellular networks needed for maintaining yeast prions are largely uncharacterized. Here, we establish a novel role for actin networks in prion maintenance. The [PIN+ ] prion, also known as [RNQ+ ], exists as stable variants dependent upon the chaperone machinery for the transmission of propagons to daughter cells during cell division and cytoplasmic transfer. Loss of the Hsp104 molecular chaperone leads to the growth of prion particles until they are too large to be transmitted. Here, we isolated a unique [PIN+ ] variant, which is unstable in actin mutants. This prion loss is observed over many generations, and coincides with the detection of both high molecular weight species of Rnq1 and large visible aggregates that are asymmetrically retained during cell division. Our data suggest that the irregular actin networks found in these mutants may influence propagon number by slowly permitting aggregate growth over time, resulting in the generation of nontransmissible large aggregates. Thus, we show the potential contribution of cytoskeletal networks in the transmission of prion propagons, which parallels models that have been proposed for cell-to-cell transmission of small amyloids in neurodegenerative protein aggregation diseases.
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Affiliation(s)
- Jane E Dorweiler
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Mitchell J Oddo
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Douglas R Lyke
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Jacob A Reilly
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Brett T Wisniewski
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Emily E Davis
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Abigail M Kuborn
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Stephen J Merrill
- Department of Mathematical and Statistical Sciences, Marquette University, Milwaukee, WI, USA
| | - Anita L Manogaran
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
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17
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Pollard LW, Garabedian MV, Alioto SL, Shekhar S, Goode BL. Genetically inspired in vitro reconstitution of Saccharomyces cerevisiae actin cables from seven purified proteins. Mol Biol Cell 2020; 31:335-347. [PMID: 31913750 PMCID: PMC7183793 DOI: 10.1091/mbc.e19-10-0576] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A major goal of synthetic biology is to define the minimal cellular machinery required to assemble a biological structure in its simplest form. Here, we focused on Saccharomyces cerevisiae actin cables, which provide polarized tracks for intracellular transport and maintain defined lengths while continuously undergoing rapid assembly and turnover. Guided by the genetic requirements for proper cable assembly and dynamics, we show that seven evolutionarily conserved S. cerevisiae proteins (actin, formin, profilin, tropomyosin, capping protein, cofilin, and AIP1) are sufficient to reconstitute the formation of cables that undergo polarized turnover and maintain steady-state lengths similar to actin cables in vivo. Further, the removal of individual proteins from this simple in vitro reconstitution system leads to cable defects that closely approximate in vivo cable phenotypes caused by disrupting the corresponding genes. Thus, a limited set of molecular components is capable of self-organizing into dynamic, micron-scale actin structures with features similar to cables in living cells.
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Affiliation(s)
| | | | | | | | - Bruce L Goode
- Department of Biology, Brandeis University, Waltham, MA 02454
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18
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Qiao Z, Sun H, Ng JTY, Ma Q, Koh SH, Mu Y, Miao Y, Gao YG. Structural and computational examination of the Arabidopsis profilin-Poly-P complex reveals mechanistic details in profilin-regulated actin assembly. J Biol Chem 2019; 294:18650-18661. [PMID: 31653702 PMCID: PMC6901310 DOI: 10.1074/jbc.ra119.011307] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 10/18/2019] [Indexed: 11/06/2022] Open
Abstract
Profilins are abundant cytosolic proteins that are universally expressed in eukaryotes and that regulate actin filament elongation by binding to both monomeric actin (G-actin) and formin proteins. The atypical profilin Arabidopsis AtPRF3 has been reported to cooperate with canonical profilin isoforms in suppressing formin-mediated actin polymerization during plant innate immunity responses. AtPRF3 has a 37-amino acid-long N-terminal extension (NTE), and its suppressive effect on actin assembly is derived from enhanced interaction with the polyproline (Poly-P) of the formin AtFH1. However, the molecular mechanism remains unclear. Here, we solved the crystal structures of AtPRF3Δ22 and AtPRF3Δ37, as well as AtPRF2 apo form and in complex with AtFH1 Poly-P at 1.5-3.6 Å resolutions. By combining these structures with molecular modeling, we found that AtPRF3Δ22 NTE has high plasticity, with a primary "closed" conformation that can adopt an open conformation that enables Poly-P binding. Furthermore, using molecular dynamics simulation and free-energy calculations of protein-protein binding, along with experimental validation, we show that the AtPRF3Δ22 binds to Poly-P in an adaptive manner, thereby enabling different binding modes that maintain the interaction through disordered sequences. Together, our structural and simulation results suggest that the dynamic conformational changes of the AtPRF3 NTE upon Poly-P binding modulate their interactions to fine-tune formin-mediated actin assembly.
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Affiliation(s)
- Zhu Qiao
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - He Sun
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - Justin Tze Yang Ng
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - Qianqian Ma
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - Si Hui Koh
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - Yuguang Mu
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore; School of Chemical and Biomedical Engineering, Nanyang Technological University, 637371 Singapore.
| | - Yong-Gui Gao
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore; Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), 138673 Singapore; Nanyang Technological University Institute of Structural Biology, Nanyang Technological University, 639798 Singapore.
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19
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Polarisome scaffolder Spa2-mediated macromolecular condensation of Aip5 for actin polymerization. Nat Commun 2019; 10:5078. [PMID: 31699995 PMCID: PMC6838200 DOI: 10.1038/s41467-019-13125-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 10/11/2019] [Indexed: 11/25/2022] Open
Abstract
A multiprotein complex polarisome nucleates actin cables for polarized cell growth in budding yeast and filamentous fungi. However, the dynamic regulations of polarisome proteins in polymerizing actin under physiological and stress conditions remains unknown. We identify a previously functionally unknown polarisome member, actin-interacting-protein 5 (Aip5), which promotes actin assembly synergistically with formin Bni1. Aip5-C terminus is responsible for its activities by interacting with G-actin and Bni1. Through N-terminal intrinsically disordered region, Aip5 forms high-order oligomers and generate cytoplasmic condensates under the stresses conditions. The molecular dynamics and reversibility of Aip5 condensates are regulated by scaffolding protein Spa2 via liquid-liquid phase separation both in vitro and in vivo. In the absence of Spa2, Aip5 condensates hamper cell growth and actin cable structures under stress treatment. The present study reveals the mechanisms of actin assembly for polarity establishment and the adaptation in stress conditions to protect actin assembly by protein phase separation. The polarisome is a dynamic protein complex that nucleates F-actin for polarized yeast growth, but its regulation is unclear. Here, the authors report that the polarisome protein Aip5 undergoes Spa2-mediated phase separation in physiological and stress conditions, potentially for regulating actin assembly.
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20
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Jones MC, Zha J, Humphries MJ. Connections between the cell cycle, cell adhesion and the cytoskeleton. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180227. [PMID: 31431178 PMCID: PMC6627016 DOI: 10.1098/rstb.2018.0227] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/26/2018] [Indexed: 12/18/2022] Open
Abstract
Cell division, the purpose of which is to enable cell replication, and in particular to distribute complete, accurate copies of genetic material to daughter cells, is essential for the propagation of life. At a morphological level, division not only necessitates duplication of cellular structures, but it also relies on polar segregation of this material followed by physical scission of the parent cell. For these fundamental changes in cell shape and positioning to be achieved, mechanisms are required to link the cell cycle to the modulation of cytoarchitecture. Outside of mitosis, the three main cytoskeletal networks not only endow cells with a physical cytoplasmic skeleton, but they also provide a mechanism for spatio-temporal sensing via integrin-associated adhesion complexes and site-directed delivery of cargoes. During mitosis, some interphase functions are retained, but the architecture of the cytoskeleton changes dramatically, and there is a need to generate a mitotic spindle for chromosome segregation. An economical solution is to re-use existing cytoskeletal molecules: transcellular actin stress fibres remodel to create a rigid cortex and a cytokinetic furrow, while unipolar radial microtubules become the primary components of the bipolar spindle. This remodelling implies the existence of specific mechanisms that link the cell-cycle machinery to the control of adhesion and the cytoskeleton. In this article, we review the intimate three-way connection between microenvironmental sensing, adhesion signalling and cell proliferation, particularly in the contexts of normal growth control and aberrant tumour progression. As the morphological changes that occur during mitosis are ancient, the mechanisms linking the cell cycle to the cytoskeleton/adhesion signalling network are likely to be primordial in nature and we discuss recent advances that have elucidated elements of this link. A particular focus is the connection between CDK1 and cell adhesion. This article is part of a discussion meeting issue 'Forces in cancer: interdisciplinary approaches in tumour mechanobiology'.
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Affiliation(s)
| | | | - Martin J. Humphries
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester M13 9PT, UK
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21
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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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22
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Vannini C, Marsoni M, Scoccianti V, Ceccarini C, Domingo G, Bracale M, Crinelli R. Proteasome-mediated remodeling of the proteome and phosphoproteome during kiwifruit pollen germination. J Proteomics 2019; 192:334-345. [DOI: 10.1016/j.jprot.2018.09.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/11/2018] [Accepted: 09/20/2018] [Indexed: 01/19/2023]
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23
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Ganesan V, Willis SD, Chang KT, Beluch S, Cooper KF, Strich R. Cyclin C directly stimulates Drp1 GTP affinity to mediate stress-induced mitochondrial hyperfission. Mol Biol Cell 2018; 30:302-311. [PMID: 30516433 PMCID: PMC6589575 DOI: 10.1091/mbc.e18-07-0463] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mitochondria exist in an equilibrium between fragmented and fused states that shifts heavily toward fission in response to cellular damage. Nuclear-to-cytoplasmic cyclin C relocalization is essential for dynamin-related protein 1 (Drp1)–dependent mitochondrial fission in response to oxidative stress. This study finds that cyclin C directly interacts with the Drp1 GTPase domain, increases its affinity to GTP, and stimulates GTPase activity in vitro. In addition, the cyclin C domain that binds Drp1 is contained within the non–Cdk binding second cyclin box domain common to all cyclin family members. This interaction is important, as this domain is sufficient to induce mitochondrial fission when expressed in mouse embryonic fibroblasts in the absence of additional stress signals. Using gel filtration chromatography and negative stain electron microscopy, we found that cyclin C interaction changes the geometry of Drp1 oligomers in vitro. High–molecular weight low–GTPase activity oligomers in the form of short filaments and rings were diminished, while dimers and elongated filaments were observed. Our results support a model in which cyclin C binding stimulates the reduction of low–GTPase activity Drp1 oligomers into dimers capable of producing high–GTPase activity filaments.
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Affiliation(s)
- Vidyaramanan Ganesan
- Department of Molecular Biology, Graduate School of Biomedical Sciences, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084
| | - Stephen D Willis
- Department of Molecular Biology, Graduate School of Biomedical Sciences, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084
| | - Kai-Ti Chang
- Department of Molecular Biology, Graduate School of Biomedical Sciences, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084
| | - Samuel Beluch
- Department of Molecular Biology, Graduate School of Biomedical Sciences, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084.,Department of Biological Sciences, Rutgers University, New Brunswick, NJ 08901
| | - Katrina F Cooper
- Department of Molecular Biology, Graduate School of Biomedical Sciences, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084
| | - Randy Strich
- Department of Molecular Biology, Graduate School of Biomedical Sciences, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084
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24
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Xie Y, Han X, Miao Y. An Effective Recombinant Protein Expression and Purification System inSaccharomyces cerevisiae. ACTA ACUST UNITED AC 2018; 123:e62. [DOI: 10.1002/cpmb.62] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Ying Xie
- School of Chemical and Biomedical Engineering, Nanyang Technological University; Singapore
| | - Xiao Han
- School of Biological Sciences, Nanyang Technological University; Singapore
| | - Yansong Miao
- School of Chemical and Biomedical Engineering, Nanyang Technological University; Singapore
- School of Biological Sciences, Nanyang Technological University; Singapore
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25
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Miao Y, Tipakornsaowapak T, Zheng L, Mu Y, Lewellyn E. Phospho-regulation of intrinsically disordered proteins for actin assembly and endocytosis. FEBS J 2018; 285:2762-2784. [PMID: 29722136 DOI: 10.1111/febs.14493] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 04/04/2018] [Accepted: 04/26/2018] [Indexed: 12/13/2022]
Abstract
Actin filament assembly contributes to the endocytic pathway pleiotropically, with active roles in clathrin-dependent and clathrin-independent endocytosis as well as subsequent endosomal trafficking. Endocytosis comprises a series of dynamic events, including the initiation of membrane curvature, bud invagination, vesicle abscission and subsequent vesicular transport. The ultimate success of endocytosis requires the coordinated activities of proteins that trigger actin polymerization, recruit actin-binding proteins (ABPs) and organize endocytic proteins (EPs) that promote membrane curvature through molecular crowding or scaffolding mechanisms. A particularly interesting phenomenon is that multiple EPs and ABPs contain a substantial percentage of intrinsically disordered regions (IDRs), which can contribute to protein coacervation and phase separation. In addition, intrinsically disordered proteins (IDPs) frequently contain sites for post-translational modifications (PTMs) such as phosphorylation, and these modifications exhibit a high preference for IDR residues [Groban ES et al. (2006) PLoS Comput Biol 2, e32]. PTMs are implicated in regulating protein function by modulating the protein conformation, protein-protein interactions and the transition between order and disorder states of IDPs. The molecular mechanisms by which IDRs of ABPs and EPs fine-tune actin assembly and endocytosis remain mostly unexplored and elusive. In this review, we analyze protein sequences of budding yeast EPs and ABPs, and discuss the potential underlying mechanisms for regulating endocytosis and actin assembly through the emerging concept of IDR-mediated protein multivalency, coacervation, and phase transition, with an emphasis on the phospho-regulation of IDRs. Finally, we summarize the current understanding of how these mechanisms coordinate actin cytoskeleton assembly and membrane curvature formation during endocytosis in budding yeast.
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Affiliation(s)
- Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.,School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | | | - Liangzhen Zheng
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Yuguang Mu
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Eric Lewellyn
- Department of Biology, Division of Natural Sciences, St Norbert College, De Pere, WI, USA
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26
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Tan JJD, Ma Z, Xie Y, Yang L, Miao Y. Quantitative analysis of actin filament assembly in yeast and plant by live cell fluorescence microscopy. Micron 2017; 103:78-83. [PMID: 28992458 DOI: 10.1016/j.micron.2017.09.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 09/25/2017] [Accepted: 09/25/2017] [Indexed: 10/18/2022]
Abstract
Eukaryotic cells depend on a dynamic actin cytoskeleton to regulate many conserved intracellular events such as endocytosis, morphogenesis, polarized cell growth, and cytokinesis (Engqvist-Goldstein and Drubin, 2003; Salbreux et al., 2012; Pruyne et al., 2004; Pollard, 2010). These activities depend on a precise and well-organized spatiotemporal actin assembly that involves many conserved processes found in eukaryotic cells ranging from a unicellular organism, such as yeast, to multicellular organisms, such as plants and human. In particular, both budding yeast Saccharomyces cerevisiae and plant Arabidopsis thaliana have been proven to be the powerful and great model organisms to study the molecular mechanisms of the polymerization of the actin cytoskeleton and the actin-driven processes in walled-cells. Here we describe the methods in imaging and image processing to analyze dynamic actin filament assembly in budding yeast and Arabidopsis using a wide-field fluorescent microscope.
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Affiliation(s)
- Joseph Jun Dao Tan
- Ageing Research Institute for Society and Education, Interdisciplinary Graduate School, Nanyang Technological University, 639798, Singapore
| | - Zhiming Ma
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Ying Xie
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 637459, Singapore
| | - Liang Yang
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore; Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, 637551, Singapore
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore; School of Chemical and Biomedical Engineering, Nanyang Technological University, 637459, Singapore.
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27
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Christensen JR, Hocky GM, Homa KE, Morganthaler AN, Hitchcock-DeGregori SE, Voth GA, Kovar DR. Competition between Tropomyosin, Fimbrin, and ADF/Cofilin drives their sorting to distinct actin filament networks. eLife 2017; 6. [PMID: 28282023 PMCID: PMC5404920 DOI: 10.7554/elife.23152] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 03/09/2017] [Indexed: 12/15/2022] Open
Abstract
The fission yeast actin cytoskeleton is an ideal, simplified system to investigate fundamental mechanisms behind cellular self-organization. By focusing on the stabilizing protein tropomyosin Cdc8, bundling protein fimbrin Fim1, and severing protein coffin Adf1, we examined how their pairwise and collective interactions with actin filaments regulate their activity and segregation to functionally diverse F-actin networks. Utilizing multi-color TIRF microscopy of in vitro reconstituted F-actin networks, we observed and characterized two distinct Cdc8 cables loading and spreading cooperatively on individual actin filaments. Furthermore, Cdc8, Fim1, and Adf1 all compete for association with F-actin by different mechanisms, and their cooperative association with actin filaments affects their ability to compete. Finally, competition between Fim1 and Adf1 for F-actin synergizes their activities, promoting rapid displacement of Cdc8 from a dense F-actin network. Our findings reveal that competitive and cooperative interactions between actin binding proteins help define their associations with different F-actin networks. DOI:http://dx.doi.org/10.7554/eLife.23152.001 Cells use a protein called actin to provide shape, to generate the forces needed for cells to divide, and for many other essential processes. Inside a cell, individual actin proteins join up to form long filaments. These actin filaments are organized in different ways to make networks that have distinct properties, each tailored for a specific process. For instance, bundles of straight actin filaments help a cell to divide, whereas a network of branched actin filaments allows cells to move. The different proteins that bind to actin filaments influence how quickly actin filaments are assembled and organized into networks. Therefore, many of the properties of an actin filament network are due to the actin binding proteins that are associated with it. Two actin binding proteins called fimbrin and cofilin associate with a type of actin filament network known as the actin patch. A third actin binding protein called tropomyosin associates with a different network that forms a ring. It is not known how particular actin binding proteins choose to associate with one actin network instead of another. Christensen et al. used a fluorescence microscopy technique to study how fimbrin, cofilin and tropomyosin associate with different actin networks in a single-celled organism called fission yeast. This technique involved incubating actin and actin binding proteins together in a microscope chamber. The experiments show that some actin binding proteins, like tropomyosin, cooperate to bind to actin. Individual tropomyosin molecules find it difficult to bind actin filaments on their own, but once one tropomyosin molecule is attached to the filament, others rapidly join to coat the filament. On the other hand, some actin-binding proteins compete for binding to filaments. For example, the binding of fimbrin to actin filaments causes tropomyosin to be removed from the actin network. Further experiments revealed that fimbrin and cofilin work with each other to rapidly generate a dense actin network and displace tropomyosin. Together, the findings of Christensen et al. suggest that competitions between actin binding proteins determine which actin binding proteins are associated with an actin network. The next challenge is to understand how the most competitive actin-binding proteins are kept off actin networks where they do not belong. Further studies will shed light on how these interactions cause large changes in how the cell is organized. DOI:http://dx.doi.org/10.7554/eLife.23152.002
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Affiliation(s)
- Jenna R Christensen
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, United States
| | - Glen M Hocky
- Department of Chemistry, The University of Chicago, Chicago, United States.,James Franck Institute, 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
| | - Sarah E Hitchcock-DeGregori
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, United States
| | - Gregory A Voth
- Department of Chemistry, The University of Chicago, Chicago, United States.,James Franck Institute, The University of Chicago, Chicago, United States.,Computation Institute, The University of Chicago, Chicago, United States.,Institute for Biophysical Dynamics, 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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