1
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Tsilafakis K, Mavroidis M. Are the Head and Tail Domains of Intermediate Filaments Really Unstructured Regions? Genes (Basel) 2024; 15:633. [PMID: 38790262 PMCID: PMC11121635 DOI: 10.3390/genes15050633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 05/01/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024] Open
Abstract
Intermediate filaments (IFs) are integral components of the cytoskeleton which provide cells with tissue-specific mechanical properties and are involved in a plethora of cellular processes. Unfortunately, due to their intricate architecture, the 3D structure of the complete molecule of IFs has remained unresolved. Even though most of the rod domain structure has been revealed by means of crystallographic analyses, the flanked head and tail domains are still mostly unknown. Only recently have studies shed light on head or tail domains of IFs, revealing certainsecondary structures and conformational changes during IF assembly. Thus, a deeper understanding of their structure could provide insights into their function.
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Affiliation(s)
- Konstantinos Tsilafakis
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece;
- Department of Biochemistry and Biotechnology, University of Thessaly, Biopolis, 41500 Larissa, Greece
| | - Manolis Mavroidis
- Center of Basic Research, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece;
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2
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Rietscher K, Homberg M, Kovalenko I, Sexton JZ, Rice RH, Has C, Omary MB, Magin TM. Painting and dissecting Epidermolysis Bullosa Simplex-associated keratin aggregates. J Dermatol Sci 2023; 112:109-111. [PMID: 37735021 DOI: 10.1016/j.jdermsci.2023.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/26/2023] [Accepted: 08/09/2023] [Indexed: 09/23/2023]
Affiliation(s)
- Katrin Rietscher
- Institute of Biology, Professorship of Cell and Developmental Biology, University of Leipzig, Leipzig, Germany.
| | - Melanie Homberg
- Institute of Biology, Professorship of Cell and Developmental Biology, University of Leipzig, Leipzig, Germany
| | - Ilya Kovalenko
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA; Department of Internal Medicine, Gastroenterology and Hepatology, Michigan Medicine at the University of Michigan, Ann Arbor, MI, USA; U-M Center for Drug Repurposing, University of Michigan, Ann Arbor, MI, USA; Insilico Medicine HK Limited, Pak Shek Kok, Hong Kong
| | - Jonathan Z Sexton
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA; Department of Internal Medicine, Gastroenterology and Hepatology, Michigan Medicine at the University of Michigan, Ann Arbor, MI, USA; U-M Center for Drug Repurposing, University of Michigan, Ann Arbor, MI, USA
| | - Robert H Rice
- Department of Environmental Toxicology, University of California, Davis, CA, USA; Forensic Science Program, University of California, Davis, CA, USA
| | - Cristina Has
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany
| | - M Bishr Omary
- Center for Advanced Biotechnology and Medicine, and Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA
| | - Thomas M Magin
- Institute of Biology, Professorship of Cell and Developmental Biology, University of Leipzig, Leipzig, Germany
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3
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Sun R, Zheng R, Zhu W, Zhou X, Liu L, Cao H. Directed Self-Assembly of Heterologously Expressed Hagfish EsTKα and EsTKγ for Functional Hydrogel. Front Bioeng Biotechnol 2022; 10:960586. [PMID: 35935505 PMCID: PMC9354048 DOI: 10.3389/fbioe.2022.960586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 06/24/2022] [Indexed: 11/13/2022] Open
Abstract
Hagfish slime proteins have long been considered useful due to their potential applications in novel green, environmental, and functional bionic materials. The two main component proteins in the slime thread of hagfish, (opt)EsTKα and (opt)EsTKγ, were used as raw materials. However, the methods available to assemble these two proteins are time- and labor-intensive. The conditions affecting protein self-assembly, such as the pH of the assembly buffer, protein concentration, and the protein addition ratio, were the subject of the present research. Through a series of tests, the self-assembly results of a variety of assembly conditions were explored. Finally, a simplified protein self-assembly method was identified that allows for simple, direct assembly of the two proteins directly. This method does not require protein purification. Under the optimal assembly conditions obtained by exploration, a new gel material was synthesized from the hagfish protein through self-assembly of the (opt)EsTKα and (opt)EsTKγ. This assembly method has the benefits of being a simple, time-saving, and efficient. The self-assembled protein gel products were verified by SDS polyacrylamide gel electrophoresis (SDS-PAGE) and contained (opt)EsTKα and (opt)EsTKγ proteins. Scanning electron microscopy (SEM) was used to investigate the self-assembled protein gel after freeze-drying, and it was observed that the self-assembled protein formed a dense, three-dimensional porous network structure, meaning that it had good water retention. Evaluation of the gel with atomic force microscopy (AFM) indicated that the surface of the protein fiber skeleton show the network-like structure and relatively smooth. Characterization by circular dichroism (CD) and Fourier transform infrared spectroscopy (FT-IR) demonstrated that the two proteins were successfully assembled, and that the assembled protein had a secondary structure dominated by α-helices. The rheological properties of the self-assembled products were tested to confirm that they were indeed hydrogel property.
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4
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Gouveia M, Sorčan T, Zemljič-Jokhadar Š, Travasso RDM, Liović M. A mathematical model for the dependence of keratin aggregate formation on the quantity of mutant keratin expressed in EGFP-K14 R125P keratinocytes. PLoS One 2021; 16:e0261227. [PMID: 34962936 PMCID: PMC8714116 DOI: 10.1371/journal.pone.0261227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/24/2021] [Indexed: 11/18/2022] Open
Abstract
We examined keratin aggregate formation and the possible mechanisms involved. With this aim, we observed the effect that different ratios between mutant and wild-type keratins expressed in cultured keratinocytes may have on aggregate formation in vitro, as well as how keratin aggregate formation affects the mechanical properties of cells at the cell cortex. To this end we prepared clones with expression rates as close as possible to 25%, 50% and 100% of the EGFP-K14 proteins (either WT or R125P and V270M mutants). Our results showed that only in the case of the 25% EGFP-K14 R125P mutant significant differences could be seen. Namely, we observed in this case the largest accumulation of keratin aggregates and a significant reduction in cell stiffness. To gain insight into the possible mechanisms behind this observation, we extended our previous mathematical model of keratin dynamics by implementing a more complex reaction network that considers the coexistence of wild-type and mutant keratins in the cell. The new model, consisting of a set of coupled, non-linear, ordinary differential equations, allowed us to draw conclusions regarding the relative amounts of intermediate filaments and aggregates in cells, and suggested that aggregate formation by asymmetric binding between wild-type and mutant keratins could explain the data obtained on cells grown in culture.
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Affiliation(s)
- Marcos Gouveia
- Department of Physics, CFisUC, Center of Physics of the University of Coimbra, University of Coimbra, Coimbra, Portugal
- * E-mail: (MG); (RDMT); (ML)
| | | | - Špela Zemljič-Jokhadar
- Faculty of Medicine, Institute for Biophysics, University of Ljubljana, Ljubljana, Slovenia
| | - Rui D. M. Travasso
- Department of Physics, CFisUC, Center of Physics of the University of Coimbra, University of Coimbra, Coimbra, Portugal
- * E-mail: (MG); (RDMT); (ML)
| | - Mirjana Liović
- Faculty of Medicine, Medical Center for Molecular Biology, Institute for Biochemistry and Molecular Genetics, University of Ljubljana, Ljubljana, Slovenia
- * E-mail: (MG); (RDMT); (ML)
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5
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Chen F, Yao L, Zhang X, Gu Y, Yu H, Yao Z, Zhang J, Li M. Damaged Keratin Filament Network Caused by KRT5 Mutations in Localized Recessive Epidermolysis Bullosa Simplex. Front Genet 2021; 12:736610. [PMID: 34912369 PMCID: PMC8667171 DOI: 10.3389/fgene.2021.736610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 10/28/2021] [Indexed: 11/21/2022] Open
Abstract
Epidermolysis bullosa simplex (EBS) is a blistering dermatosis that is mostly caused by dominant mutations in KRT5 and KRT14. In this study, we investigated one patient with localized recessive EBS caused by novel homozygous c.1474T > C mutations in KRT5. Biochemical experiments showed a mutation-induced alteration in the keratin 5 structure, intraepidermal blisters, and collapsed keratin intermediate filaments, but no quantitative change at the protein levels and interaction between keratin 5 and keratin 14. Moreover, we found that MAPK signaling was inhibited, while desmosomal protein desmoglein 1 (DSG1) was upregulated upon KRT5 mutation. Inhibition of EGFR phosphorylation upregulated DSG1 levels in an in vitro model. Collectively, our findings suggest that this mutation leads to localized recessive EBS and that keratin 5 is involved in maintaining DSG1 via activating MAPK signaling.
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Affiliation(s)
- Fuying Chen
- Department of Dermatology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Institute of Dermatology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Lei Yao
- Experiment Medicine Center, The Affiliated Hospital of Southwest Medical University, Luzhou, China.,Academician (Expert) Workstation of Sichuan Province, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Xue Zhang
- Department of Dermatology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Institute of Dermatology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yan Gu
- Department of Dermatology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Institute of Dermatology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hong Yu
- Department of Dermatology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Zhirong Yao
- Department of Dermatology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Institute of Dermatology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jia Zhang
- Department of Dermatology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Institute of Dermatology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Ming Li
- Department of Dermatology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Institute of Dermatology, Shanghai Jiaotong University School of Medicine, Shanghai, China
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6
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Vermeire PJ, Stalmans G, Lilina AV, Fiala J, Novak P, Herrmann H, Strelkov SV. Molecular Interactions Driving Intermediate Filament Assembly. Cells 2021; 10:cells10092457. [PMID: 34572105 PMCID: PMC8466517 DOI: 10.3390/cells10092457] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/31/2021] [Accepted: 09/03/2021] [Indexed: 02/06/2023] Open
Abstract
Given the role of intermediate filaments (IFs) in normal cell physiology and scores of IF-linked diseases, the importance of understanding their molecular structure is beyond doubt. Research into the IF structure was initiated more than 30 years ago, and some important advances have been made. Using crystallography and other methods, the central coiled-coil domain of the elementary dimer and also the structural basis of the soluble tetramer formation have been studied to atomic precision. However, the molecular interactions driving later stages of the filament assembly are still not fully understood. For cytoplasmic IFs, much of the currently available insight is due to chemical cross-linking experiments that date back to the 1990s. This technique has since been radically improved, and several groups have utilized it recently to obtain data on lamin filament assembly. Here, we will summarize these findings and reflect on the remaining open questions and challenges of IF structure. We argue that, in addition to X-ray crystallography, chemical cross-linking and cryoelectron microscopy are the techniques that should enable major new advances in the field in the near future.
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Affiliation(s)
- Pieter-Jan Vermeire
- Laboratory for Biocrystallography, KU Leuven, 3000 Leuven, Belgium; (P.-J.V.); (G.S.); (A.V.L.)
| | - Giel Stalmans
- Laboratory for Biocrystallography, KU Leuven, 3000 Leuven, Belgium; (P.-J.V.); (G.S.); (A.V.L.)
| | - Anastasia V. Lilina
- Laboratory for Biocrystallography, KU Leuven, 3000 Leuven, Belgium; (P.-J.V.); (G.S.); (A.V.L.)
| | - Jan Fiala
- Department of Biochemistry, Charles University, 12800 Prague, Czech Republic; (J.F.); (P.N.)
- Institute of Microbiology of the Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Petr Novak
- Department of Biochemistry, Charles University, 12800 Prague, Czech Republic; (J.F.); (P.N.)
- Institute of Microbiology of the Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Harald Herrmann
- Institute of Neuropathology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany;
| | - Sergei V. Strelkov
- Laboratory for Biocrystallography, KU Leuven, 3000 Leuven, Belgium; (P.-J.V.); (G.S.); (A.V.L.)
- Correspondence: ; Tel.: +32-1633-0845
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7
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Weber MS, Eibauer M, Sivagurunathan S, Magin TM, Goldman RD, Medalia O. Structural heterogeneity of cellular K5/K14 filaments as revealed by cryo-electron microscopy. eLife 2021; 10:70307. [PMID: 34323216 PMCID: PMC8360650 DOI: 10.7554/elife.70307] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/23/2021] [Indexed: 12/11/2022] Open
Abstract
Keratin intermediate filaments are an essential and major component of the cytoskeleton in epithelial cells. They form a stable yet dynamic filamentous network extending from the nucleus to the cell periphery, which provides resistance to mechanical stresses. Mutations in keratin genes are related to a variety of epithelial tissue diseases. Despite their importance, the molecular structure of keratin filaments remains largely unknown. In this study, we analyzed the structure of keratin 5/keratin 14 filaments within ghost mouse keratinocytes by cryo-electron microscopy and cryo-electron tomography. By averaging a large number of keratin segments, we have gained insights into the helical architecture of the filaments. Two-dimensional classification revealed profound variations in the diameter of keratin filaments and their subunit organization. Computational reconstitution of filaments of substantial length uncovered a high degree of internal heterogeneity along single filaments, which can contain regions of helical symmetry, regions with less symmetry and regions with significant diameter fluctuations. Cross-section views of filaments revealed that keratins form hollow cylinders consisting of multiple protofilaments, with an electron dense core located in the center of the filament. These findings shed light on the complex and remarkable heterogenic architecture of keratin filaments, suggesting that they are highly flexible, dynamic cytoskeletal structures.
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Affiliation(s)
- Miriam S Weber
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Matthias Eibauer
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Suganya Sivagurunathan
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, United States
| | - Thomas M Magin
- Institute of Biology, University of Leipzig, Leipzig, Germany
| | - Robert D Goldman
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, United States
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
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8
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Yamamoto M, Sakamoto Y, Honda Y, Koike K, Nakamura H, Matsumoto T, Ando S. De novo filament formation by human hair keratins K85 and K35 follows a filament development pattern distinct from cytokeratin filament networks. FEBS Open Bio 2021; 11:1299-1312. [PMID: 33605551 PMCID: PMC8091587 DOI: 10.1002/2211-5463.13126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 01/24/2021] [Accepted: 02/18/2021] [Indexed: 11/23/2022] Open
Abstract
In human hair follicles, the hair‐forming cells express 16 hair keratin genes depending on the differentiation stages. K85 and K35 are the first hair keratins expressed in cortical cells at the early stage of the differentiation. Two types of mutations in the gene encoding K85 are associated with ectodermal dysplasia of hair and nail type. Here, we transfected cultured SW‐13 cells with human K85 and K35 genes and characterized filament formation. The K85–K35 pair formed short filaments in the cytoplasm, which gradually elongated and became thicker and entangled around the nucleus, indicating that K85–K35 promotes lateral association of short intermediate filaments (IFs) into bundles but cannot form IF networks in the cytoplasm. Of the K85 mutations related to ectodermal dysplasia of hair and nail type, a two‐nucleotide (C1448T1449) deletion (delCT) in the protein tail domain of K85 interfered with the K85–K35 filament formation and gave only aggregates, whereas a missense mutation (233A>G) that replaces Arg78 with His (R78H) in the head domain of K85 did not interfere with the filament formation. Transfection of cultured MCF‐7 cells with all the hair keratin gene combinations, K85–K35, K85(R78H)–K35 and K85(delCT)–K35, as well as the individual hair keratin genes, formed well‐developed cytoplasmic IF networks, probably by incorporating into the endogenous cytokeratin IF networks. Thus, the unique de novo assembly properties of the K85–K35 pair might play a key role in the early stage of hair formation.
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Affiliation(s)
- Masaki Yamamoto
- Faculty of Biotechnology and Life Science, Sojo University, Kumamoto, Japan
| | - Yasuko Sakamoto
- Faculty of Biotechnology and Life Science, Sojo University, Kumamoto, Japan
| | - Yuko Honda
- Faculty of Medicine, Saga University, Japan
| | - Kenzo Koike
- Hair Care Research Center, KAO Corporation, Tokyo, Japan
| | - Hideaki Nakamura
- Faculty of Pharmaceutical Science, Sojo University, Kumamoto, Japan
| | | | - Shoji Ando
- Faculty of Biotechnology and Life Science, Sojo University, Kumamoto, Japan
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9
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Lehmann SM, Leube RE, Windoffer R. Growth, lifetime, directional movement and myosin-dependent motility of mutant keratin granules in cultured cells. Sci Rep 2021; 11:2379. [PMID: 33504849 PMCID: PMC7840912 DOI: 10.1038/s41598-021-81542-8] [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] [Received: 11/13/2020] [Accepted: 01/08/2021] [Indexed: 11/09/2022] Open
Abstract
Intermediate filament polypeptides (IFPs) are prominent components of cytoplasmic aggregates, which are pathognomonic for multiple diseases. Recent observations in cultured cells suggest that they are dynamic and subject to regulated turnover. The emerging concept is that multiple factors contribute to motility and turnover of IFP-containing aggregates. To understand their relative contribution, quantitative tools are needed. The current study addresses this need using epithelial cells producing mutant keratin IFPs that have been identified as the cause of the hereditary blister-forming skin disease epidermolysis bullosa simplex. Digital image analysis of individual granules allowed mapping of their complete life cycle, with information on multiple characteristics at any given time-point. The deduced signet features revealed rapid granule fusion and directed transport from the periphery towards the cell centre, and a limited, ~ 30 min lifetime with a slow, continuous growth phase followed by fast disassembly. As paradigmatic proof-of-principle, we demonstrate that inhibition of myosin II selectively reduces granule movement, linking keratin granule motility to retrograde cortical acto-myosin flow. The newly developed methods and established parameters will help in the characterization of known and the identification of novel regulators of IFP-containing aggregates.
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Affiliation(s)
- S M Lehmann
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074, Aachen, Germany
| | - R E Leube
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074, Aachen, Germany.
| | - R Windoffer
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Wendlingweg 2, 52074, Aachen, Germany
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10
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Lai HY, Setyawati MI, Ferhan AR, Divakarla SK, Chua HM, Cho NJ, Chrzanowski W, Ng KW. Self-Assembly of Solubilized Human Hair Keratins. ACS Biomater Sci Eng 2021; 7:83-89. [PMID: 33356132 DOI: 10.1021/acsbiomaterials.0c01507] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human hair keratins have proven to be a viable biomaterial for diverse regenerative applications. However, the most significant characteristic of this material, the ability to self-assemble into nanoscale intermediate filaments, has not been exploited. Herein, we successfully demonstrated the induction of hair-extracted keratin self-assembly in vitro to form dense, homogeneous, and continuous nanofibrous networks. These networks remain hydrolytically stable in vitro for up to 5 days in complete cell culture media and are compatible with primary human dermal fibroblasts and keratinocytes. These results enhance the versatility of human hair keratins for applications where structured assembly is of benefit.
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Affiliation(s)
- Hui Ying Lai
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.,Nanyang Environment & Water Research Institute (Environmental Chemistry and Materials Centre), Interdisciplinary Graduate Program, Nanyang Technological University, Singapore
| | - Magdiel Inggrid Setyawati
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Abdul Rahim Ferhan
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Shiva Kamini Divakarla
- The University of Sydney, Sydney Nano Institute, Faculty of Medicine and Health, Sydney Pharmacy School, Sydney, New South Wales 2006, Australia
| | - Huei Min Chua
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Nam-Joon Cho
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Wojciech Chrzanowski
- The University of Sydney, Sydney Nano Institute, Faculty of Medicine and Health, Sydney Pharmacy School, Sydney, New South Wales 2006, Australia
| | - Kee Woei Ng
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.,Nanyang Environment & Water Research Institute (Environmental Chemistry and Materials Centre), Interdisciplinary Graduate Program, Nanyang Technological University, Singapore.,Skin Research Institute of Singapore, Biomedical Science Institutes, Immunos, 8A Biomedical Grove, Singapore 138648, Singapore.,Department of Environmental Health, Harvard T.H. Chan School of Public Health, 665 Huntington Avenue, Boston, Massachusetts 02115, United States
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11
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Lin EW, Brady GF, Kwan R, Nesvizhskii AI, Omary MB. Genotype-phenotype analysis of LMNA-related diseases predicts phenotype-selective alterations in lamin phosphorylation. FASEB J 2020; 34:9051-9073. [PMID: 32413188 PMCID: PMC8059629 DOI: 10.1096/fj.202000500r] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/12/2020] [Accepted: 04/15/2020] [Indexed: 12/17/2022]
Abstract
Laminopathies are rare diseases associated with mutations in LMNA, which encodes nuclear lamin A/C. LMNA variants lead to diverse tissue-specific phenotypes including cardiomyopathy, lipodystrophy, myopathy, neuropathy, progeria, bone/skin disorders, and overlap syndromes. The mechanisms underlying these heterogeneous phenotypes remain poorly understood, although post-translational modifications, including phosphorylation, are postulated as regulators of lamin function. We catalogued all known lamin A/C human mutations and their associated phenotypes, and systematically examined the putative role of phosphorylation in laminopathies. In silico prediction of specific LMNA mutant-driven changes to lamin A phosphorylation and protein structure was performed using machine learning methods. Some of the predictions we generated were validated via assessment of ectopically expressed wild-type and mutant LMNA. Our findings indicate phenotype- and mutant-specific alterations in lamin phosphorylation, and that some changes in phosphorylation may occur independently of predicted changes in lamin protein structure. Therefore, therapeutic targeting of phosphorylation in the context of laminopathies will likely require mutant- and kinase-specific approaches.
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Affiliation(s)
- Eric W Lin
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Graham F Brady
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Raymond Kwan
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA
| | - Alexey I Nesvizhskii
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - M Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA
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12
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Gouveia M, Zemljič-Jokhadar Š, Vidak M, Stojkovič B, Derganc J, Travasso R, Liovic M. Keratin Dynamics and Spatial Distribution in Wild-Type and K14 R125P Mutant Cells-A Computational Model. Int J Mol Sci 2020; 21:E2596. [PMID: 32283594 PMCID: PMC7177522 DOI: 10.3390/ijms21072596] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 12/30/2022] Open
Abstract
Keratins are one of the most abundant proteins in epithelial cells. They form a cytoskeletal filament network whose structural organization seriously conditions its function. Dynamic keratin particles and aggregates are often observed at the periphery of mutant keratinocytes related to the hereditary skin disorder epidermolysis bullosa simplex, which is due to mutations in keratins 5 and 14. To account for their emergence in mutant cells, we extended an existing mathematical model of keratin turnover in wild-type cells and developed a novel 2D phase-field model to predict the keratin distribution inside the cell. This model includes the turnover between soluble, particulate and filamentous keratin forms. We assumed that the mutation causes a slowdown in the assembly of an intermediate keratin phase into filaments, and demonstrated that this change is enough to account for the loss of keratin filaments in the cell's interior and the emergence of keratin particles at its periphery. The developed mathematical model is also particularly tailored to model the spatial distribution of keratins as the cell changes its shape.
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Affiliation(s)
- Marcos Gouveia
- CFisUC, Center for Physics of the University of Coimbra, Department of Physics, University of Coimbra, R Larga, 3004-516 Coimbra, Portugal
| | - Špela Zemljič-Jokhadar
- Institute for Biophysics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia; (Š.Z.-J.); (B.S.); (J.D.)
| | - Marko Vidak
- Medical Center for Molecular Biology, Institute for Biochemistry, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia; (M.V.); (M.L.)
| | - Biljana Stojkovič
- Institute for Biophysics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia; (Š.Z.-J.); (B.S.); (J.D.)
| | - Jure Derganc
- Institute for Biophysics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia; (Š.Z.-J.); (B.S.); (J.D.)
| | - Rui Travasso
- CFisUC, Center for Physics of the University of Coimbra, Department of Physics, University of Coimbra, R Larga, 3004-516 Coimbra, Portugal
| | - Mirjana Liovic
- Medical Center for Molecular Biology, Institute for Biochemistry, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia; (M.V.); (M.L.)
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13
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Broussard JA, Jaiganesh A, Zarkoob H, Conway DE, Dunn AR, Espinosa HD, Janmey PA, Green KJ. Scaling up single-cell mechanics to multicellular tissues - the role of the intermediate filament-desmosome network. J Cell Sci 2020; 133:jcs228031. [PMID: 32179593 PMCID: PMC7097224 DOI: 10.1242/jcs.228031] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cells and tissues sense, respond to and translate mechanical forces into biochemical signals through mechanotransduction, which governs individual cell responses that drive gene expression, metabolic pathways and cell motility, and determines how cells work together in tissues. Mechanotransduction often depends on cytoskeletal networks and their attachment sites that physically couple cells to each other and to the extracellular matrix. One way that cells associate with each other is through Ca2+-dependent adhesion molecules called cadherins, which mediate cell-cell interactions through adherens junctions, thereby anchoring and organizing the cortical actin cytoskeleton. This actin-based network confers dynamic properties to cell sheets and developing organisms. However, these contractile networks do not work alone but in concert with other cytoarchitectural elements, including a diverse network of intermediate filaments. This Review takes a close look at the intermediate filament network and its associated intercellular junctions, desmosomes. We provide evidence that this system not only ensures tissue integrity, but also cooperates with other networks to create more complex tissues with emerging properties in sensing and responding to increasingly stressful environments. We will also draw attention to how defects in intermediate filament and desmosome networks result in both chronic and acquired diseases.
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Affiliation(s)
- Joshua A Broussard
- Departments of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| | - Avinash Jaiganesh
- Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Hoda Zarkoob
- Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Daniel E Conway
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Alexander R Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Horacio D Espinosa
- Department of Mechanical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Paul A Janmey
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kathleen J Green
- Departments of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
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14
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Lorenz C, Forsting J, Schepers AV, Kraxner J, Bauch S, Witt H, Klumpp S, Köster S. Lateral Subunit Coupling Determines Intermediate Filament Mechanics. PHYSICAL REVIEW LETTERS 2019; 123:188102. [PMID: 31763918 DOI: 10.1103/physrevlett.123.188102] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Indexed: 05/27/2023]
Abstract
The cytoskeleton is a composite network of three types of protein filaments, among which intermediate filaments (IFs) are the most extensible ones. Two very important IFs are keratin and vimentin, which have similar molecular architectures but different mechanical behaviors. Here we compare the mechanical response of single keratin and vimentin filaments using optical tweezers. We show that the mechanics of vimentin strongly depends on the ionic strength of the buffer and that its force-strain curve suggests a high degree of cooperativity between subunits. Indeed, a computational model indicates that in contrast to keratin, vimentin is characterized by strong lateral subunit coupling of its charged monomers during unfolding of α helices. We conclude that cells can tune their mechanics by differential use of keratin versus vimentin.
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Affiliation(s)
- Charlotta Lorenz
- Institute for X-Ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Johanna Forsting
- Institute for X-Ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Anna V Schepers
- Institute for X-Ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Julia Kraxner
- Institute for X-Ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Susanne Bauch
- Institute for X-Ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Hannes Witt
- Institute for Organic and Biomolecular Chemistry, University of Göttingen, Tammanstraße 2, 37077 Göttingen, Germany
- Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 7, 37077 Göttingen
| | - Stefan Klumpp
- Institute for Dynamics of Complex Systems, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Sarah Köster
- Institute for X-Ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
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15
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Shibuya K, Tsutsui S, Nakamura O. Fugu, Takifugu ruberipes, mucus keratins act as defense molecules against fungi. Mol Immunol 2019; 116:1-10. [PMID: 31561060 DOI: 10.1016/j.molimm.2019.09.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 12/20/2022]
Abstract
Keratin is a cytoskeletal protein that constitutes the intermediate filament. Its distribution is restricted to epithelial tissues in mammals, but is wider in fish. An interesting feature of fish keratin is that it is abundant in the cutaneous mucus. However, the biological function of keratin in the mucus has not been explored. In the present study, we hypothesized that mucus keratins of fugu Takifugu rubripes function as antimicrobial molecules. To verify this hypothesis, we first identified all of the keratins expressed in the epidermis and present in mucus. Five of 15 keratins including Tr-K4 expressed in the epidermis were identified in the mucus. Subsequently, we examined the interaction of keratin molecules present in fugu mucus with yeast. Affinity chromatography using yeast as a carrier and subsequent LC-MS/MS analysis revealed that three types of keratin were bound to the yeast. Furthermore, yeast incubated with fugu mucus was agglutinated, and this was inhibited by anti-recombinant Tr-K4 (rTr-K4) antibody. Immunohistochemical analysis also revealed that keratin was attached to the surface of agglutinated yeasts. These findings indicate that mucus keratin agglutinates yeast. Furthermore, we found insoluble clumps in fugu mucus, which were mainly comprised of keratin. After incubation of yeast with soluble mucus fraction, insoluble clumps incorporating yeast were formed. This observation suggests that fugu mucus keratin sequesters microbes into insoluble clumps, which are eventually eliminated from the mucus. Here, we present our finding of the novel function of keratin as a defense molecule in fish mucus.
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Affiliation(s)
- Ko Shibuya
- School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Shigeyuki Tsutsui
- School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Osamu Nakamura
- School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan.
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16
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Javadi A, Söderholm N, Olofsson A, Flärdh K, Sandblad L. Assembly mechanisms of the bacterial cytoskeletal protein FilP. Life Sci Alliance 2019; 2:2/3/e201800290. [PMID: 31243049 PMCID: PMC6599971 DOI: 10.26508/lsa.201800290] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 06/13/2019] [Accepted: 06/14/2019] [Indexed: 11/29/2022] Open
Abstract
FilP is a coiled-coil protein that self-assembles into striated filaments and meshwork that shares structural and biochemical characteristics with metazoan intermediate filaments. Despite low-sequence homology, the intermediate filament (IF)–like protein FilP from Streptomyces coelicolor displays structural and biochemical similarities to the metazoan nuclear IF lamin. FilP, like IF proteins, is composed of central coiled-coil domains interrupted by short linkers and flanked by head and tail domains. FilP polymerizes into repetitive filament bundles with paracrystalline properties. However, the cations Na+ and K+ are found to induce the formation of a FilP hexagonal meshwork with the same 60-nm repetitive unit as the filaments. Studies of polymerization kinetics, in combination with EM techniques, enabled visualization of the basic building block—a transiently soluble rod-shaped FilP molecule—and its assembly into protofilaments and filament bundles. Cryoelectron tomography provided a 3D view of the FilP bundle structure and an original assembly model of an IF-like protein of prokaryotic origin, thereby enabling a comparison with the assembly of metazoan IF.
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Affiliation(s)
- Ala Javadi
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | | | | | - Klas Flärdh
- Department of Biology, Lund University, Lund, Sweden
| | - Linda Sandblad
- Department of Molecular Biology, Umeå University, Umeå, Sweden
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17
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Golde T, Glaser M, Tutmarc C, Elbalasy I, Huster C, Busteros G, Smith DM, Herrmann H, Käs JA, Schnauß J. The role of stickiness in the rheology of semiflexible polymers. SOFT MATTER 2019; 15:4865-4872. [PMID: 31161188 DOI: 10.1039/c9sm00433e] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Semiflexible polymers form central structures in biological material. Modelling approaches usually neglect influences of polymer-specific molecular features aiming to describe semiflexible polymers universally. Here, we investigate the influence of molecular details on networks assembled from filamentous actin, intermediate filaments, and synthetic DNA nanotubes. In contrast to prevalent theoretical assumptions, we find that bulk properties are affected by various inter-filament interactions. We present evidence that these interactions can be merged into a single parameter in the frame of the glassy wormlike chain model. The interpretation of this parameter as a polymer specific stickiness is consistent with observations from macro-rheological measurements and reptation behaviour. Our findings demonstrate that stickiness should generally not be ignored in semiflexible polymer models.
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Affiliation(s)
- Tom Golde
- Peter Debye Institute for Soft Matter Physics, University of Leipzig, 04103 Leipzig, Germany.
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18
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Eldirany SA, Ho M, Hinbest AJ, Lomakin IB, Bunick CG. Human keratin 1/10-1B tetramer structures reveal a knob-pocket mechanism in intermediate filament assembly. EMBO J 2019; 38:embj.2018100741. [PMID: 31036554 PMCID: PMC6545558 DOI: 10.15252/embj.2018100741] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 03/06/2019] [Accepted: 03/14/2019] [Indexed: 01/07/2023] Open
Abstract
To characterize keratin intermediate filament assembly mechanisms at atomic resolution, we determined the crystal structure of wild-type human keratin-1/keratin-10 helix 1B heterotetramer at 3.0 Å resolution. It revealed biochemical determinants for the A11 mode of axial alignment in keratin filaments. Four regions on a hydrophobic face of the K1/K10-1B heterodimer dictated tetramer assembly: the N-terminal hydrophobic pocket (defined by L227K1, Y230K1, F231K1, and F234K1), the K10 hydrophobic stripe, K1 interaction residues, and the C-terminal anchoring knob (formed by F314K1 and L318K1). Mutation of both knob residues to alanine disrupted keratin 1B tetramer and full-length filament assembly. Individual knob residue mutant F314AK1, but not L318AK1, abolished 1B tetramer formation. The K1-1B knob/pocket mechanism is conserved across keratins and many non-keratin intermediate filaments. To demonstrate how pathogenic mutations cause skin disease by altering filament assembly, we additionally determined the 2.39 Å structure of K1/10-1B containing a S233LK1 mutation linked to epidermolytic palmoplantar keratoderma. Light scattering and circular dichroism measurements demonstrated enhanced aggregation of K1S233L/K10-1B in solution without affecting secondary structure. The K1S233L/K10-1B octamer structure revealed S233LK1 causes aberrant hydrophobic interactions between 1B tetramers.
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Affiliation(s)
| | - Minh Ho
- Department of DermatologyYale UniversityNew HavenCTUSA
| | | | - Ivan B Lomakin
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenCTUSA
| | - Christopher G Bunick
- Department of DermatologyYale UniversityNew HavenCTUSA,Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenCTUSA
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19
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Gao F, Li W, Deng J, Kan J, Guo T, Wang B, Hao S. Recombinant Human Hair Keratin Nanoparticles Accelerate Dermal Wound Healing. ACS APPLIED MATERIALS & INTERFACES 2019; 11:18681-18690. [PMID: 31038908 DOI: 10.1021/acsami.9b01725] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In recent years, favorable enhanced wound-healing properties and excellent biocompatibility of keratin derived from human hair have attracted considerable attention. Recombinant keratin proteins can be produced by recombinant DNA technology and have higher purity than extracted keratin. However, the wound-healing properties of recombinant keratin proteins remain unclear. Herein, two recombinant trichocyte keratins including human type I hair keratin 37 and human type II hair keratin 81 were expressed using a bacterial expression system, and recombinant keratin nanoparticles (RKNPs) were prepared via an ultrasonic dispersion method. The molecular weight, purity, and physicochemical properties of the recombinant keratin proteins and nanoparticles were assessed using gel electrophoresis, circular dichroism, mass spectrometry, and scanning electron microscope analyses. The RKNPs significantly enhanced cell proliferation and migration in vitro, and the treatment of dermal wounds in vivo with RKNPs resulted in improved wound healing associated with improved epithelialization, vascularization, and collagen deposition and remodeling. In addition, the in vivo biocompatibility test revealed no systemic toxicity. Overall, this work demonstrates that RKNPs are a promising candidate for enhanced wound healing, and this study opens up new prospects for the development of keratin biomaterials.
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Affiliation(s)
- Feiyan Gao
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering , Chongqing University , Chongqing 400030 , China
| | - Wenfeng Li
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering , Chongqing University , Chongqing 400030 , China
| | - Jia Deng
- College of Environment and Resources , Chongqing Technology and Business University , Chongqing 400067 , China
| | - Jinlan Kan
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering , Chongqing University , Chongqing 400030 , China
| | - Tingwang Guo
- College of Environment and Resources , Chongqing Technology and Business University , Chongqing 400067 , China
| | - Bochu Wang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering , Chongqing University , Chongqing 400030 , China
| | - Shilei Hao
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering , Chongqing University , Chongqing 400030 , China
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20
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Favre B, Begré N, Bouameur JE, Lingasamy P, Conover GM, Fontao L, Borradori L. Desmoplakin interacts with the coil 1 of different types of intermediate filament proteins and displays high affinity for assembled intermediate filaments. PLoS One 2018; 13:e0205038. [PMID: 30286183 PMCID: PMC6171917 DOI: 10.1371/journal.pone.0205038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 09/18/2018] [Indexed: 12/04/2022] Open
Abstract
The interaction of intermediate filaments (IFs) with the cell-cell adhesion complexes desmosomes is crucial for cytoskeletal organization and cell resilience in the epidermis and heart. The intracellular desmosomal protein desmoplakin anchors IFs to the cell adhesion complexes predominantly via its four last carboxy-terminal domains (C-terminus). However, it remains unclear why the C-terminus of desmoplakin interacts with different IF types or if there are different binding affinities for each type of IFs that may influence the stability of cell-specific adhesion complexes. By yeast three-hybrid and fluorescence binding assays, we found that the coiled-coil 1 of the conserved central rod domain of the heterodimeric cytokeratins (Ks) 5 and 14 (K5/K14) was required for their interaction with the C-terminus of desmoplakin, while their unique amino head- and C-tail domains were dispensable. Similar findings were obtained in vitro with K1/K10, and the type III IF proteins desmin and vimentin. Binding assays testing the C-terminus of desmoplakin with assembled K5/K14 and desmin IFs yielded an apparent affinity in the nM range. Our findings reveal that the same conserved domain of IF proteins binds to the C-terminus of desmoplakin, which may help explain the previously reported broad binding IF-specificity to desmoplakin. Our data suggest that desmoplakin high-affinity binding to diverse IF proteins ensures robust linkages of IF cytoskeleton and desmosomes that maintain the structural integrity of cellular adhesion complexes. In summary, our results give new insights into the molecular basis of the IF-desmosome association.
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Affiliation(s)
- Bertrand Favre
- Department of Dermatology, Inselspital, Bern University Hospital, Bern, Switzerland
- Department for Biomedical Research, University of Bern, Bern, Switzerland
| | - Nadja Begré
- Department of Dermatology, Inselspital, Bern University Hospital, Bern, Switzerland
- Department for Biomedical Research, University of Bern, Bern, Switzerland
| | - Jamal-Eddine Bouameur
- Department of Dermatology, Inselspital, Bern University Hospital, Bern, Switzerland
- Department for Biomedical Research, University of Bern, Bern, Switzerland
| | - Prakash Lingasamy
- Department of Dermatology, Inselspital, Bern University Hospital, Bern, Switzerland
- Department for Biomedical Research, University of Bern, Bern, Switzerland
| | - Gloria M. Conover
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas, United States of America
| | - Lionel Fontao
- Department of Dermatology, Geneva University Hospitals, Geneva, Switzerland
| | - Luca Borradori
- Department of Dermatology, Inselspital, Bern University Hospital, Bern, Switzerland
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21
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Deek J, Maan R, Loiseau E, Bausch AR. Reconstitution of composite actin and keratin networks in vesicles. SOFT MATTER 2018; 14:1897-1902. [PMID: 29464258 DOI: 10.1039/c7sm00819h] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Although cytoskeletal networks are interpenetrating and interacting in living cells, very little is understood as to the effect their interaction has on their properties. Here, as a step towards elucidating the synergistic cellular role of these structural proteins, we investigate isolated keratin and actin composites and show how the in vitro network formation of keratin influences the properties of actin networks and vice versa. By encapsulating purified composite networks into vesicles and separating the time scales of network formation we are able to demonstrate that the actin network stabilizes keratin networks by providing an elastic resistance to their collapse in vitro.
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Affiliation(s)
- J Deek
- Lehrstuhl für Zellbiophysik E27, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany.
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22
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Abstract
Macrofibrils are the main structural component of the hair cortex, and are a composite material in which trichokeratin intermediate filaments (IFs) are arranged as organised arrays embedded in a matrix composed of keratin-associated proteins (KAPs) and keratin head groups. Various architecture of macrofibrils is possible, with many having a central core around which IFs are helically arranged, an organisation most accurately described as a double-twist arrangement. In this chapter we describe the architecture of macrofibrils and then cover their formation, with most of the material focusing on the theory that the initial stages of macrofibril formation are as liquid crystals.
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23
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Fraser RDB, Parry DAD. Structural Hierarchy of Trichocyte Keratin Intermediate Filaments. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1054:57-70. [PMID: 29797268 DOI: 10.1007/978-981-10-8195-8_6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Although trichocyte keratins (hair, wool, quill, claw) have been studied since the 1930s it is only over the last 30 years or so that major advances have been made in our understanding of the complex structural hierarchy of the filamentous component of this important filament-matrix composite. A variety of techniques, including amino acid sequence analysis, computer modelling, X-ray fibre diffraction and protein crystallography, various forms of electron microscopy, and crosslinking methods have now combined to reveal much of the structural detail. The heterodimeric structure of the keratin molecule is clear, as are the highly-specific modes by which these molecules aggregate to form functionally viable IF. The observation that hair keratin can adopt not one but two structurally-distinct conformations, one formed in the living cells at the base of the hair follicle in a reducing environment and the second in the fully differentiated hair in dead cells in an oxidized state, was unexpected but has major implications for the mechanism of hair growth. Insights have also been made into the mechanism of the uppermost level of hair superstructure, relating to the assembly of the IF in the paracortical and orthocortical macrofibrils.
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Affiliation(s)
- R D Bruce Fraser
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,, Tewantin, QLD, Australia
| | - David A D Parry
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand. .,Riddet Institute, Massey University, Palmerston North, New Zealand.
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24
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Vidmar B, Vodovnik M. Microbial Keratinases: Enzymes with Promising Biotechnological Applications. Food Technol Biotechnol 2018; 56:312-328. [PMID: 30510475 PMCID: PMC6233012 DOI: 10.17113/ftb.56.03.18.5658] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Keratin is a complex and structurally stable protein found in human and animal hard tissues, such as feathers, wool, hair, hoof and nails. Some of these, like feathers and wool, represent one of the main sources of protein-rich waste with significant potential to be transformed into value-added products such as feed, fertilizers or bioenergy. A major limitation impeding valorization of keratinous substrates is their recalcitrant structure and resistance to hydrolysis by common proteases. However, specialized keratinolytic enzymes produced by some microorganisms can efficiently degrade these substrates. Keratinases have already found a purpose in pharmaceutical, textile and leather industries. However, their wider implementation in other processes, such as cost-effective (pre)treatment of poultry waste, still requires optimization of production and performance of the available enzymes. Here we present a comprehensive review covering molecular properties and characteristics of keratinases, their classification, traditional and novel approaches in discovery of novel enzymes, production, characterization, improvement and biotechnological applications.
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Affiliation(s)
- Beti Vidmar
- Chair of Microbiology and Microbial Biotechnology, Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3,
SI-1230 Domžale, Slovenia
| | - Maša Vodovnik
- Chair of Microbiology and Microbial Biotechnology, Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3,
SI-1230 Domžale, Slovenia
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25
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Sawant M, Schwarz N, Windoffer R, Magin TM, Krieger J, Mücke N, Obara B, Jankowski V, Jankowski J, Wally V, Lettner T, Leube RE. Threonine 150 Phosphorylation of Keratin 5 Is Linked to Epidermolysis Bullosa Simplex and Regulates Filament Assembly and Cell Viability. J Invest Dermatol 2017; 138:627-636. [PMID: 29080682 DOI: 10.1016/j.jid.2017.10.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/11/2017] [Accepted: 10/08/2017] [Indexed: 10/18/2022]
Abstract
A characteristic feature of the skin blistering disease epidermolysis bullosa simplex is keratin filament (KF) network collapse caused by aggregation of the basal epidermal keratin type II (KtyII) K5 and its type I partner keratin 14 (K14). Here, we examine the role of keratin phosphorylation in KF network rearrangement and cellular functions. We detect phosphorylation of the K5 head domain residue T150 in cytoplasmic epidermolysis bullosa simplex granules containing R125C K14 mutants. Expression of phosphomimetic T150D K5 mutants results in impaired KF formation in keratinocytes. The phenotype is enhanced upon combination with other phosphomimetic K5 head domain mutations. Remarkably, introduction of T150D K5 mutants into KtyII-lacking (KtyII-/-) keratinocytes prevents keratin network formation altogether. In contrast, phosphorylation-deficient T150A K5 leads to KFs with reduced branching and turnover. Assembly of T150D K5 is arrested at the heterotetramer stage coinciding with increased heat shock protein association. Finally, reduced cell viability and elevated response to stressors is noted in T150 mutant cells. Taken together, our findings identify T150 K5 phosphorylation as an important determinant of KF network formation and function with a possible role in epidermolysis bullosa simplex pathogenesis.
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Affiliation(s)
- Mugdha Sawant
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Aachen, Germany
| | - Nicole Schwarz
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Aachen, Germany
| | - Reinhard Windoffer
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Aachen, Germany
| | - Thomas M Magin
- Institute of Biology and Translational Center for Regenerative Medicine, University of Leipzig, Leipzig, Germany
| | - Jan Krieger
- Biophysics of Macromolecules, German Cancer Research Center, Heidelberg, Germany
| | - Norbert Mücke
- Biophysics of Macromolecules, German Cancer Research Center, Heidelberg, Germany
| | - Boguslaw Obara
- School of Engineering and Computing Sciences, Durham University, Durham, UK
| | - Vera Jankowski
- Institut für Molekulare Herz-Kreislaufforschung, RWTH Aachen University, Aachen, Germany
| | - Joachim Jankowski
- Institut für Molekulare Herz-Kreislaufforschung, RWTH Aachen University, Aachen, Germany; School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
| | - Verena Wally
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Thomas Lettner
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Aachen, Germany.
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26
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Fu J, Guerette PA, Pavesi A, Horbelt N, Lim CT, Harrington MJ, Miserez A. Artificial hagfish protein fibers with ultra-high and tunable stiffness. NANOSCALE 2017; 9:12908-12915. [PMID: 28832693 DOI: 10.1039/c7nr02527k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Stiff fibers are used as reinforcing phases in a wide range of high-performance composite materials. Silk is one of the most widely studied bio-fibers, but alternative materials with specific advantages are also being explored. Among these, native hagfish (Eptatretus stoutii) slime thread is an attractive protein-based polymer. These threads consist of coiled-coil intermediate filaments (IFs) as nano-scale building blocks, which can be transformed into extended β-sheet-containing chains upon draw-processing, resulting in fibers with impressive mechanical performance. Here, we report artificial hagfish threads produced by recombinant protein expression, which were subsequently self-assembled into coiled-coil nanofilaments, concentrated, and processed into β-sheet-rich fibers by a "picking-up" method. These artificial fibers experienced mechanical performance enhancement during draw-processing. We exploited the lysine content to covalently cross-link the draw-processed fibers and obtained moduli values (E) in tension as high as ∼20 GPa, which is stiffer than most reported artificial proteinaceous materials.
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Affiliation(s)
- Jing Fu
- School of Materials Science and Engineering, Nanyang Technological University (NTU), Singapore 639798
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27
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Parker RN, Roth KL, Kim C, McCord JP, Van Dyke ME, Grove TZ. Homo- and heteropolymer self-assembly of recombinant trichocytic keratins. Biopolymers 2017; 107. [PMID: 28741310 DOI: 10.1002/bip.23037] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/30/2017] [Accepted: 07/05/2017] [Indexed: 12/13/2022]
Abstract
In the past two decades, keratin biomaterials have shown impressive results as scaffolds for tissue engineering, wound healing, and nerve regeneration. In addition to its intrinsic biocompatibility, keratin interacts with specific cell receptors eliciting beneficial biochemical cues. However, during extraction from natural sources, such as hair and wool fibers, natural keratins are subject to extensive processing conditions that lead to formation of unwanted by-products. Additionally, natural keratins suffer from limited sequence tunability. Recombinant keratin proteins can overcome these drawbacks while maintaining the desired chemical and physical characteristics of natural keratins. Herein, we present the bacterial expression, purification, and solution characterization of human hair keratins K31 and K81. The obligate heterodimerization of the K31/K81 pair that results in formation of intermediate filaments is maintained in the recombinant proteins. Surprisingly, we have for the first time observed new zero- and one-dimensional nanostructures from homooligomerization of K81 and K31, respectively. Further analysis of the self-assembly mechanism highlights the importance of disulfide crosslinking in keratin self-assembly.
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Affiliation(s)
- Rachael N Parker
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia, 24060
| | - Kristina L Roth
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia, 24060
| | - Christina Kim
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia, 24060
| | - Jennifer P McCord
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia, 24060
| | - Mark E Van Dyke
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia, 24060
| | - Tijana Z Grove
- Department of Chemistry and Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia, 24060
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28
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Hatzfeld M, Keil R, Magin TM. Desmosomes and Intermediate Filaments: Their Consequences for Tissue Mechanics. Cold Spring Harb Perspect Biol 2017; 9:a029157. [PMID: 28096266 PMCID: PMC5453391 DOI: 10.1101/cshperspect.a029157] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Adherens junctions (AJs) and desmosomes connect the actin and keratin filament networks of adjacent cells into a mechanical unit. Whereas AJs function in mechanosensing and in transducing mechanical forces between the plasma membrane and the actomyosin cytoskeleton, desmosomes and intermediate filaments (IFs) provide mechanical stability required to maintain tissue architecture and integrity when the tissues are exposed to mechanical stress. Desmosomes are essential for stable intercellular cohesion, whereas keratins determine cell mechanics but are not involved in generating tension. Here, we summarize the current knowledge of the role of IFs and desmosomes in tissue mechanics and discuss whether the desmosome-keratin scaffold might be actively involved in mechanosensing and in the conversion of chemical signals into mechanical strength.
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Affiliation(s)
- Mechthild Hatzfeld
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, 06114 Halle, Germany
| | - René Keil
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, 06114 Halle, Germany
| | - Thomas M Magin
- Institute of Biology, Division of Cell and Developmental Biology and Saxonian Incubator for Clinical Translation (SIKT), University of Leipzig, 04103 Leipzig, Germany
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29
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Deek J, Hecht F, Rossetti L, Wißmiller K, Bausch AR. Mechanics of soft epithelial keratin networks depend on modular filament assembly kinetics. Acta Biomater 2016; 43:218-229. [PMID: 27403885 DOI: 10.1016/j.actbio.2016.07.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 06/04/2016] [Accepted: 07/09/2016] [Indexed: 11/15/2022]
Abstract
UNLABELLED Structural adaptability is a pivotal requirement of cytoskeletal structures, enabling their reorganization to meet the cellular needs. Shear stress, for instance, results in large morphological network changes of the human soft epithelial keratin pair K8:K18, and is accompanied by an increase in keratin phosphorylation levels. Yet the mechanisms responsible for the disruption of the network structure in vivo remain poorly understood. To understand the effect of the stress-related site-specific phosphorylation of the K8:K18 pair, we created phosphomimicry mutants - K8(S431E), K8(S73E), K18(S52E) - in vitro, and investigated the various steps of keratin assembly from monomer to network structure using fluorescence and electron microscopy, and using rheology characterized their network mechanical properties. We find that the addition of a charged group produces networks with depleted intra-connectivity, which translates to a mechanically weaker and more deformable network. This large variation in network structure is achieved by the formation of shorter mutant filaments, which exhibit differing assembly kinetics and a manifestly reduced capacity to form the extended structures characteristic of the wild-type system. The similarity in outcome for all the phosphomimicry mutants explored points to a more general mechanism of structural modulation of intermediate filaments via phosphorylation. Understanding the role of kinetic effects in the construction of these cytoskeletal biopolymer networks is critical to elucidating their structure-function properties, providing new insight for the design of keratin-inspired biomaterials. STATEMENT OF SIGNIFICANCE Structural remodeling of cytoskeletal networks accompanies many cellular processes. Interestingly, levels of phosphorylation of the human soft epithelial keratin pair K8:K18 increase during their stress-related structural remodeling. Our multi-scale study sheds light on the poorly understood mechanism with which site-specific phosphorylation induces disruption of the keratin network structure in vivo. We show how phosphorylation reduces keratin filament length, an effect that propagates through to the mesoscopic structure, resulting in the formation of connectivity-depleted and mechanically weaker networks. We determine that the intrinsically-set filament-to-filament attractions that drive bundle assembly give rise to the structural variability by enabling the formation of kinetically-arrested structures. Overall, our results shed light on how self-assembled intermediate filament structures can be tailored to exhibit different structural functionalities.
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Affiliation(s)
- Joanna Deek
- Lehrstuhl für Zellbiophysik E27, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Fabian Hecht
- Lehrstuhl für Zellbiophysik E27, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Leone Rossetti
- Lehrstuhl für Zellbiophysik E27, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Katharina Wißmiller
- Lehrstuhl für Zellbiophysik E27, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Andreas R Bausch
- Lehrstuhl für Zellbiophysik E27, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany.
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30
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Nafeey S, Martin I, Felder T, Walther P, Felder E. Branching of keratin intermediate filaments. J Struct Biol 2016; 194:415-22. [PMID: 27039023 DOI: 10.1016/j.jsb.2016.03.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 03/22/2016] [Accepted: 03/30/2016] [Indexed: 11/18/2022]
Abstract
Keratin intermediate filaments (IFs) are crucial to maintain mechanical stability in epithelial cells. Since little is known about the network architecture that provides this stiffness and especially about branching properties of filaments, we addressed this question with different electron microscopic (EM) methods. Using EM tomography of high pressure frozen keratinocytes, we investigated the course of several filaments in a branching of a filament bundle. Moreover we found several putative bifurcations in individual filaments. To verify our observation we also visualized the keratin network in detergent extracted keratinocytes with scanning EM. Here bifurcations of individual filaments could unambiguously be identified additionally to bundle branchings. Interestingly, identical filament bifurcations were also found in purified keratin 8/18 filaments expressed in Escherichia coli which were reassembled in vitro. This excludes that an accessory protein contributes to the branch formation. Measurements of the filament cross sectional areas showed various ratios between the three bifurcation arms. This demonstrates that intermediate filament furcation is very different from actin furcation where an entire new filament is attached to an existing filament. Instead, the architecture of intermediate filament bifurcations is less predetermined and hence consistent with the general concept of IF formation.
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Affiliation(s)
- Soufi Nafeey
- Central Facility for Electron Microscopy, Ulm University, 89081 Ulm, Germany
| | - Ines Martin
- Institute of Experimental Physics, Ulm University, 89081 Ulm, Germany
| | - Tatiana Felder
- Institute of General Physiology, Ulm University, 89081 Ulm, Germany
| | - Paul Walther
- Central Facility for Electron Microscopy, Ulm University, 89081 Ulm, Germany.
| | - Edward Felder
- Institute of General Physiology, Ulm University, 89081 Ulm, Germany
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31
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Saldanha O, Brennich ME, Burghammer M, Herrmann H, Köster S. The filament forming reactions of vimentin tetramers studied in a serial-inlet microflow device by small angle x-ray scattering. BIOMICROFLUIDICS 2016; 10:024108. [PMID: 27042250 PMCID: PMC4798992 DOI: 10.1063/1.4943916] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/02/2016] [Indexed: 05/16/2023]
Abstract
The structural organization of metazoan cells and their shape are established through the coordinated interaction of a composite network consisting of three individual filament systems, collectively termed the cytoskeleton. Specifically, microtubules and actin filaments, which assemble from monomeric globular proteins, provide polar structures that serve motor proteins as tracks. In contrast, intermediate filaments (IFs) assemble from highly charged, extended coiled coils in a hierarchical assembly mechanism of lateral and longitudinal interaction steps into non-polar structures. IF proteins are expressed in a distinctly tissue-specific way and thereby serve to generate the precise plasticity of the respective cells and tissues. Accordingly, in the cell, numerous parameters such as pH and salt concentration are adjusted such that the generation of functional networks is ensured. Here, we transfer the problem for the mesenchymal IF protein vimentin to an in vitro setting and combine small angle x-ray scattering with microfluidics and finite element method simulations. Our approach is adapted to resolve the early assembly steps, which take place in the sub-second to second range. In particular, we reveal the influence of ion species and concentrations on the assembly. By tuning the flow rates and thus concentration profiles, we find a minimal critical salt concentration for the initiation of the assembly. Furthermore, our analysis of the surface sensitive Porod regime in the x-ray data reveals that the formation of first assembly intermediates, so-called unit length filaments, is not a one-step reaction but consists of distinct consecutive lateral association steps followed by radial compaction as well as smoothening of the surface of the full-width filament.
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Affiliation(s)
- Oliva Saldanha
- Institute for X-Ray Physics, Georg-August-Universität Göttingen , 37077 Göttingen, Germany
| | - Martha E Brennich
- Institute for X-Ray Physics, Georg-August-Universität Göttingen , 37077 Göttingen, Germany
| | | | | | - Sarah Köster
- Institute for X-Ray Physics, Georg-August-Universität Göttingen , 37077 Göttingen, Germany
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32
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Fujiwara S, Ohashi K, Mashiko T, Kondo H, Mizuno K. Interplay between Solo and keratin filaments is crucial for mechanical force-induced stress fiber reinforcement. Mol Biol Cell 2016; 27:954-66. [PMID: 26823019 PMCID: PMC4791139 DOI: 10.1091/mbc.e15-06-0417] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 01/15/2016] [Indexed: 11/11/2022] Open
Abstract
Mechanical force-induced cytoskeletal reorganization is essential for cell and tissue remodeling and homeostasis; however, the underlying cellular mechanisms remain elusive. Solo (ARHGEF40) is a RhoA-targeting guanine nucleotide exchange factor (GEF) involved in cyclical stretch-induced human endothelial cell reorientation and convergent extension cell movement in zebrafish gastrula. In this study, we show that Solo binds to keratin-8/keratin-18 (K8/K18) intermediate filaments through multiple sites. Solo overexpression promotes the formation of thick actin stress fibers and keratin bundles, whereas knockdown of Solo, expression of a GEF-inactive mutant of Solo, or inhibition of ROCK suppresses stress fiber formation and leads to disorganized keratin networks, indicating that the Solo-RhoA-ROCK pathway serves to precisely organize keratin networks, as well as to promote stress fibers. Of importance, knockdown of Solo or K18 or overexpression of GEF-inactive or deletion mutants of Solo suppresses tensile force-induced stress fiber reinforcement. Furthermore, knockdown of Solo or K18 suppresses tensile force-induced RhoA activation. These results strongly suggest that the interplay between Solo and K8/K18 filaments plays a crucial role in tensile force-induced RhoA activation and consequent actin cytoskeletal reinforcement.
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Affiliation(s)
- Sachiko Fujiwara
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Kazumasa Ohashi
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Toshiya Mashiko
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Hiroshi Kondo
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Kensaku Mizuno
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
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33
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Premchandar A, Kupniewska A, Tarnowski K, Mücke N, Mauermann M, Kaus-Drobek M, Edelman A, Herrmann H, Dadlez M. Analysis of distinct molecular assembly complexes of keratin K8 and K18 by hydrogen–deuterium exchange. J Struct Biol 2015; 192:426-440. [DOI: 10.1016/j.jsb.2015.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/24/2015] [Accepted: 10/01/2015] [Indexed: 02/06/2023]
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Abstract
Keratins comprise the type I and type II intermediate filament-forming proteins and occur primarily in epithelial cells. They are encoded by 54 evolutionarily conserved genes (28 type I, 26 type II) and regulated in a pairwise and tissue type-, differentiation-, and context-dependent manner. Keratins serve multiple homeostatic and stress-enhanced mechanical and nonmechanical functions in epithelia, including the maintenance of cellular integrity, regulation of cell growth and migration, and protection from apoptosis. These functions are tightly regulated by posttranslational modifications as well as keratin-associated proteins. Genetically determined alterations in keratin-coding sequences underlie highly penetrant and rare disorders whose pathophysiology reflects cell fragility and/or altered tissue homeostasis. Moreover, keratin mutation or misregulation represents risk factors or genetic modifiers for several acute and chronic diseases. This chapter focuses on keratins that are expressed in skin epithelia, and details a number of basic protocols and assays that have proven useful for analyses being carried out in skin.
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Affiliation(s)
- Fengrong Wang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Abigail Zieman
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Pierre A Coulombe
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA; Department of Biological Chemistry, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA; Department of Dermatology, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA; Department of Oncology, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.
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35
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Homberg M, Ramms L, Schwarz N, Dreissen G, Leube RE, Merkel R, Hoffmann B, Magin TM. Distinct Impact of Two Keratin Mutations Causing Epidermolysis Bullosa Simplex on Keratinocyte Adhesion and Stiffness. J Invest Dermatol 2015; 135:2437-2445. [DOI: 10.1038/jid.2015.184] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 04/10/2015] [Accepted: 04/25/2015] [Indexed: 12/20/2022]
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36
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Hémonnot CYJ, Mauermann M, Herrmann H, Köster S. Assembly of Simple Epithelial Keratin Filaments: Deciphering the Ion Dependence in Filament Organization. Biomacromolecules 2015; 16:3313-21. [PMID: 26327161 DOI: 10.1021/acs.biomac.5b00965] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The intermediate filament proteins keratin K8 and K18 constitute an essential part of the cytoskeleton in simple epithelial cell layers, structurally enforcing their mechanical resistance. K8/K18 heterodimers form extended filaments and higher-order structures including bundles and networks that bind to cell junctions. We study the assembly of these proteins in the presence of monovalent or divalent ions by small-angle X-ray scattering. We find that both ion species cause an increase of the filament diameter when their concentration is increased; albeit, much higher values are needed for the monovalent compared to the divalent ions for the same effect. Bundling occurs also for monovalent ions and at comparatively low concentrations of divalent ions, very different from vimentin intermediate filaments, a fibroblast-specific cytoskeleton component. We explain these differences by variations in charge and hydrophobicity patterns of the proteins. These differences may reflect the respective physiological situation in stationary cell layers versus single migrating fibroblasts.
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Affiliation(s)
- Clément Y J Hémonnot
- Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Monika Mauermann
- Division of Molecular Genetics, German Cancer Research Center , Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Harald Herrmann
- Division of Molecular Genetics, German Cancer Research Center , Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Sarah Köster
- Institute for X-ray Physics, University of Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
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37
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Zwerger M, Roschitzki-Voser H, Zbinden R, Denais C, Herrmann H, Lammerding J, Grütter MG, Medalia O. Altering lamina assembly reveals lamina-dependent and -independent functions for A-type lamins. J Cell Sci 2015; 128:3607-20. [PMID: 26275827 DOI: 10.1242/jcs.171843] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 08/13/2015] [Indexed: 01/26/2023] Open
Abstract
Lamins are intermediate filament proteins that form a fibrous meshwork, called the nuclear lamina, between the inner nuclear membrane and peripheral heterochromatin of metazoan cells. The assembly and incorporation of lamin A/C into the lamina, as well as their various functions, are still not well understood. Here, we employed designed ankyrin repeat proteins (DARPins) as new experimental tools for lamin research. We screened for DARPins that specifically bound to lamin A/C, and interfered with lamin assembly in vitro and with incorporation of lamin A/C into the native lamina in living cells. The selected DARPins inhibited lamin assembly and delocalized A-type lamins to the nucleoplasm without modifying lamin expression levels or the amino acid sequence. Using these lamin binders, we demonstrate the importance of proper integration of lamin A/C into the lamina for nuclear mechanical properties and nuclear envelope integrity. Finally, our study provides evidence for cell-type-specific differences in lamin functions.
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Affiliation(s)
- Monika Zwerger
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Heidi Roschitzki-Voser
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Reto Zbinden
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Celine Denais
- Cornell University, Weill Institute for Cell and Molecular Biology, Department of Biomedical Engineering, Weill Hall, Ithaca, NY 14853, USA
| | - Harald Herrmann
- Functional Architecture of the Cell, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Jan Lammerding
- Cornell University, Weill Institute for Cell and Molecular Biology, Department of Biomedical Engineering, Weill Hall, Ithaca, NY 14853, USA
| | - Markus G Grütter
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University, Beer-Sheva 84105, Israel
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38
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Fu J, Guerette PA, Miserez A. Self-Assembly of Recombinant Hagfish Thread Keratins Amenable to a Strain-Induced α-Helix to β-Sheet Transition. Biomacromolecules 2015; 16:2327-39. [PMID: 26102237 DOI: 10.1021/acs.biomac.5b00552] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hagfish slime threads are assembled from protein-based bundles of intermediate filaments (IFs) that undergo a strain-induced α-helical coiled-coil to β-sheet transition. Draw processing of native fibers enables the creation of mechanically tuned materials, and under optimized conditions this process results in mechanical properties similar to spider dragline silk. In this study, we develop the foundation for the engineering of biomimetic recombinant hagfish thread keratin (TK)-based materials. The two protein constituents from the hagfish Eptatretus stoutii thread, named EsTKα and EsTKγ, were expressed in Escherichia coli and purified. Individual (rec)EsTKs and mixtures thereof were subjected to stepwise dialysis to evaluate their protein solubility, folding, and self-assembly propensities. Conditions were identified that resulted in the self-assembly of coiled-coil rich IF-like filaments, as determined by circular dichroism (CD) and transmission electron microscopy (TEM). Rheology experiments indicated that the concentrated filaments assembled into gel-like networks exhibiting a rheological response reminiscent to that of IFs. Notably, the self-assembled filaments underwent an α-helical coiled-coil to β-sheet transition when subjected to oscillatory shear, thus mimicking the critical characteristic responsible for mechanical strengthening of native hagfish threads. We propose that our data establish the foundation to create robust and tunable recombinant TK-based materials whose mechanical properties are controlled by a strain-induced α-helical coiled-coil to β-sheet transition.
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Affiliation(s)
- Jing Fu
- †School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
| | - Paul A Guerette
- †School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798.,‡Energy Research Institute at Nanyang Technological University (ERI@N), 50 Nanyang Drive, Singapore, 637553
| | - Ali Miserez
- †School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798.,§School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive Singapore 637551
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39
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Feng X, Coulombe PA. A role for disulfide bonding in keratin intermediate filament organization and dynamics in skin keratinocytes. ACTA ACUST UNITED AC 2015; 209:59-72. [PMID: 25869667 PMCID: PMC4395492 DOI: 10.1083/jcb.201408079] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Disulfide bonds involving cysteine 367 in K14 play a crucial role in the assembly, dynamics, and organization of K14-containing filaments in epidermal keratinocytes. We recently reported that a trans-dimer, homotypic disulfide bond involving Cys367 in keratin 14 (K14) occurs in an atomic-resolution structure of the interacting K5/K14 2B domains and in keratinocyte cell lines. Here we show that a sizable fraction of the K14 and K5 protein pools participates in interkeratin disulfide bonding in primary cultures of mouse skin keratinocytes. By comparing the properties of wild-type K14 with a completely cysteine-free variant thereof, we found that K14-dependent disulfide bonding limited filament elongation during polymerization in vitro but was necessary for the genesis of a perinuclear-concentrated network of keratin filaments, normal keratin cycling, and the sessile behavior of the nucleus and whole cell in keratinocytes studied by live imaging. Many of these phenotypes were rescued when analyzing a K14 variant harboring a single Cys residue at position 367. These findings establish disulfide bonding as a novel and important mechanism regulating the assembly, intracellular organization, and dynamics of K14-containing intermediate filaments in skin keratinocytes.
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Affiliation(s)
- Xia Feng
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health; and Department of Biological Chemistry and Department of Dermatology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205
| | - Pierre A Coulombe
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health; and Department of Biological Chemistry and Department of Dermatology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205 Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health; and Department of Biological Chemistry and Department of Dermatology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205 Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health; and Department of Biological Chemistry and Department of Dermatology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205
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40
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Block J, Schroeder V, Pawelzyk P, Willenbacher N, Köster S. Physical properties of cytoplasmic intermediate filaments. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:3053-64. [PMID: 25975455 DOI: 10.1016/j.bbamcr.2015.05.009] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 04/28/2015] [Accepted: 05/05/2015] [Indexed: 11/29/2022]
Abstract
Intermediate filaments (IFs) constitute a sophisticated filament system in the cytoplasm of eukaryotes. They form bundles and networks with adapted viscoelastic properties and are strongly interconnected with the other filament types, microfilaments and microtubules. IFs are cell type specific and apart from biochemical functions, they act as mechanical entities to provide stability and resilience to cells and tissues. We review the physical properties of these abundant structural proteins including both in vitro studies and cell experiments. IFs are hierarchical structures and their physical properties seem to a large part be encoded in the very specific architecture of the biopolymers. Thus, we begin our review by presenting the assembly mechanism, followed by the mechanical properties of individual filaments, network and structure formation due to electrostatic interactions, and eventually the mechanics of in vitro and cellular networks. This article is part of a Special Issue entitled: Mechanobiology.
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Affiliation(s)
- Johanna Block
- Institut für Röntgenphysik, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Viktor Schroeder
- Institut für Röntgenphysik, Georg-August-Universität Göttingen, Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Paul Pawelzyk
- Institute of Mechanical Process Engineering and Mechanics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Norbert Willenbacher
- Institute of Mechanical Process Engineering and Mechanics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Sarah Köster
- Institut für Röntgenphysik, Georg-August-Universität Göttingen, Göttingen, Germany; Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany.
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41
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The tail domain is essential but the head domain dispensable for C. elegans intermediate filament IFA-2 function. PLoS One 2015; 10:e0119282. [PMID: 25742641 PMCID: PMC4351089 DOI: 10.1371/journal.pone.0119282] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 01/19/2015] [Indexed: 01/12/2023] Open
Abstract
The intermediate filament protein IFA-2 is essential for the structural integrity of the Caenorhabditis elegans epidermis. It is one of the major components of the fibrous organelle, an epidermal structure comprised of apical and basal hemidesmosomes linked by cytoplasmic intermediate filaments that serve to transmit force from the muscle to the cuticle. Mutations of IFA-2 result in epidermal fragility and separation of the apical and basal epidermal surfaces during postembryonic growth. An IFA-2 lacking the head domain fully rescues the IFA-2 null mutant, whereas an IFA-2 lacking the tail domain cannot. Conversely, an isolated IFA-2 head was able to localize to fibrous organelles whereas the tail was not. Taken together these results suggest that the head domain contains redundant signals for IF localization, whereas non-redundant essential functions map to the IFA-2, tail, although the tail is unlikely to be directly involved in fibrous organelle localization.
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42
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Dammann C, Herrmann H, Köster S. Competitive Counterion Binding Regulates the Aggregation Onset of Vimentin Intermediate Filaments. Isr J Chem 2015. [DOI: 10.1002/ijch.201400153] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Christian Dammann
- Institute for X-Ray Physics; University of Göttingen; Friedrich-Hund-Platz 1 D-37077 Göttingen Germany
| | - Harald Herrmann
- B065 Functional Architecture of the Cell; German Cancer Research Center (DKFZ); D-69120 Heidelberg Germany)
| | - Sarah Köster
- Institute for X-Ray Physics; University of Göttingen; Friedrich-Hund-Platz 1 D-37077 Göttingen Germany
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Pawelzyk P, Mücke N, Herrmann H, Willenbacher N. Attractive interactions among intermediate filaments determine network mechanics in vitro. PLoS One 2014; 9:e93194. [PMID: 24690778 PMCID: PMC3972185 DOI: 10.1371/journal.pone.0093194] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Accepted: 02/28/2014] [Indexed: 01/11/2023] Open
Abstract
Mechanical and structural properties of K8/K18 and vimentin intermediate filament (IF) networks have been investigated using bulk mechanical rheometry and optical microrheology including diffusing wave spectroscopy and multiple particle tracking. A high elastic modulus G0 at low protein concentration c, a weak concentration dependency of G0 (G0∼c0.5±0.1) and pronounced strain stiffening are found for these systems even without external crossbridgers. Strong attractive interactions among filaments are required to maintain these characteristic mechanical features, which have also been reported for various other IF networks. Filament assembly, the persistence length of the filaments and the network mesh size remain essentially unaffected when a nonionic surfactant is added, but strain stiffening is completely suppressed, G0 drops by orders of magnitude and exhibits a scaling G0∼c1.9±0.2 in agreement with microrheological measurements and as expected for entangled networks of semi-flexible polymers. Tailless K8Δ/K18ΔT and various other tailless filament networks do not exhibit strain stiffening, but still show high G0 values. Therefore, two binding sites are proposed to exist in IF networks. A weaker one mediated by hydrophobic amino acid clusters in the central rod prevents stretched filaments between adjacent cross-links from thermal equilibration and thus provides the high G0 values. Another strong one facilitating strain stiffening is located in the tail domain with its high fraction of hydrophobic amino acid sequences. Strain stiffening is less pronounced for vimentin than for K8/K18 due to electrostatic repulsion forces partly compensating the strong attraction at filament contact points.
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Affiliation(s)
- Paul Pawelzyk
- Institute for Mechanical Process Engineering and Mechanics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Norbert Mücke
- Biophysics of Macromolecules, German Cancer Research Center, Heidelberg, Germany
| | - Harald Herrmann
- Division of Molecular Genetics, German Cancer Research Center, Heidelberg, Germany
| | - Norbert Willenbacher
- Institute for Mechanical Process Engineering and Mechanics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- * E-mail:
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44
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Brennich ME, Bauch S, Vainio U, Wedig T, Herrmann H, Köster S. Impact of ion valency on the assembly of vimentin studied by quantitative small angle X-ray scattering. SOFT MATTER 2014; 10:2059-68. [PMID: 24800271 DOI: 10.1039/c3sm52532e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The assembly kinetics of intermediate filament (IF) proteins from tetrameric complexes to single filaments and networks depends on the protein concentration, temperature and the ionic composition of their environment. We systematically investigate how changes in the concentration of monovalent potassium and divalent magnesium ions affect the internal organization of the resulting filaments. Small angle X-ray scattering (SAXS) is very sensitive to changes in the filament cross-section such as diameter or compactness. Our measurements reveal that filaments formed in the presence of magnesium chloride differ distinctly from filaments formed in the presence of potassium chloride. The principle multi-step assembly mechanism from tetramers via unit-length filaments (ULF) to elongated filaments is not changed by the valency of ions. However, the observed differences indicate that the magnesium ions free the head domains of tetramers from unproductive interactions to allow assembly but at the same time mediate strong inter-tetrameric interactions that impede longitudinal annealing of unit-length filaments considerably, thus slowing down filament growth.
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45
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Abstract
Cystic Fibrosis Transmembrane conductance Regulator, CFTR, is a membrane protein expressed in epithelia. A protein kinase A (PKA)-regulated Cl(-) channel, it is a rate-limiting factor in fluid transport. Mutations in CFTR are responsible for cystic fibrosis, CF, an autosomal recessive disease. The most frequent mutation is deletion of phenylalanine at position 508, ΔF508. The regulation of trafficking and degradation of CFTR/ΔF508CFTR as well as its function(s) is a complex process which involves a number of proteins including chaperones and adaptors. It is now known that cytoskeletal proteins, previously considered only as structural proteins, are also important factors in the regulation of cellular processes and functions. The aim of the present review is to focus on how microfilaments, microtubules and intermediary filaments form a dynamic interactome with CFTR to participate in the regulation of CFTR-dependent transepithelial ion transport, CFTR trafficking and degradation.
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46
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Honda Y, Koike K, Kubo Y, Masuko S, Arakawa Y, Ando S. In vitro assembly properties of human type I and II hair keratins. Cell Struct Funct 2014; 39:31-43. [PMID: 24430440 DOI: 10.1247/csf.13021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Multiple type I and II hair keratins are expressed in hair-forming cells but the role of each protein in hair fiber formation remains obscure. In this study, recombinant proteins of human type I hair keratins (K35, K36 and K38) and type II hair keratins (K81 and K85) were prepared using bacterial expression systems. The heterotypic subunit interactions between the type I and II hair keratins were characterized using two-dimensional gel electrophoresis and surface plasmon resonance (SPR). Gel electrophoresis showed that the heterotypic complex-forming urea concentrations differ depending on the combination of keratins. K35-K85 and K36-K81 formed relatively stable heterotypic complexes. SPR revealed that soluble K35 bound to immobilized K85 with a higher affinity than to immobilized K81. The in vitro intermediate filament (IF) assembly of the hair keratins was explored by negative-staining electron microscopy. While K35-K81, K36-K81 and K35-K36-K81 formed IFs, K35-K85 afforded tight bundles of short IFs and large paracrystalline assemblies, and K36-K85 formed IF tangles. K85 promotes lateral association rather than elongation of short IFs. The in vitro assembly properties of hair keratins depended on the combination of type I and II hair keratins. Our data suggest the functional significance of K35-K85 and K36-K81 with distinct assembly properties in the formation of macrofibrils.
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Affiliation(s)
- Yuko Honda
- Department of Anatomy and Physiology, Faculty of Medicine, Saga University
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47
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Affiliation(s)
- Rebecca L Haines
- Epithelial Biology Group, Institute of Medical Biology, Immunos, Singapore
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48
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Leitner A, Paust T, Marti O, Walther P, Herrmann H, Beil M. Properties of intermediate filament networks assembled from keratin 8 and 18 in the presence of Mg²+. Biophys J 2012; 103:195-201. [PMID: 22853896 PMCID: PMC3403007 DOI: 10.1016/j.bpj.2012.06.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 06/04/2012] [Accepted: 06/06/2012] [Indexed: 01/10/2023] Open
Abstract
The mechanical properties of epithelial cells are modulated by structural changes in keratin intermediate filament networks. To investigate the relationship between network architecture and viscoelasticity, we assembled keratin filaments from recombinant keratin proteins 8 (K8) and 18 (K18) in the presence of divalent ions (Mg(2+)). We probed the viscoelastic modulus of the network by tracking the movement of microspheres embedded in the network during assembly, and studied the network architecture using scanning electron microscopy. Addition of Mg(2+) at physiological concentrations (<1 mM) resulted in networks whose structure was similar to that of keratin networks in epithelial cells. Moreover, the elastic moduli of networks assembled in vitro were found to be within the same magnitude as those measured in keratin networks of detergent-extracted epithelial cells. These findings suggest that Mg(2+)-induced filament cross-linking represents a valid model for studying the cytoskeletal mechanics of keratin networks.
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Affiliation(s)
- Anke Leitner
- Institut für Experimentelle Physik, University of Ulm, Ulm, Germany
| | - Tobias Paust
- Institut für Experimentelle Physik, University of Ulm, Ulm, Germany
| | - Othmar Marti
- Institut für Experimentelle Physik, University of Ulm, Ulm, Germany
| | - Paul Walther
- Electron Microscopy Facility, University of Ulm, Ulm, Germany
| | - Harald Herrmann
- Division of Molecular Genetics, German Cancer Research Center, Heidelberg, Germany
| | - Michael Beil
- Department of Medicine I, University of Ulm, Ulm, Germany
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49
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Windoffer R, Beil M, Magin TM, Leube RE. Cytoskeleton in motion: the dynamics of keratin intermediate filaments in epithelia. ACTA ACUST UNITED AC 2012; 194:669-78. [PMID: 21893596 PMCID: PMC3171125 DOI: 10.1083/jcb.201008095] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Epithelia are exposed to multiple forms of stress. Keratin intermediate filaments are abundant in epithelia and form cytoskeletal networks that contribute to cell type–specific functions, such as adhesion, migration, and metabolism. A perpetual keratin filament turnover cycle supports these functions. This multistep process keeps the cytoskeleton in motion, facilitating rapid and protein biosynthesis–independent network remodeling while maintaining an intact network. The current challenge is to unravel the molecular mechanisms underlying the regulation of the keratin cycle in relation to actin and microtubule networks and in the context of epithelial tissue function.
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Affiliation(s)
- Reinhard Windoffer
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52057 Aachen, Germany
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50
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Strnad P, Usachov V, Debes C, Gräter F, Parry DAD, Omary MB. Unique amino acid signatures that are evolutionarily conserved distinguish simple-type, epidermal and hair keratins. J Cell Sci 2012; 124:4221-32. [PMID: 22215855 DOI: 10.1242/jcs.089516] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Keratins (Ks) consist of central α-helical rod domains that are flanked by non-α-helical head and tail domains. The cellular abundance of keratins, coupled with their selective cell expression patterns, suggests that they diversified to fulfill tissue-specific functions although the primary structure differences between them have not been comprehensively compared. We analyzed keratin sequences from many species: K1, K2, K5, K9, K10, K14 were studied as representatives of epidermal keratins, and compared with K7, K8, K18, K19, K20 and K31, K35, K81, K85, K86, which represent simple-type (single-layered or glandular) epithelial and hair keratins, respectively. We show that keratin domains have striking differences in their amino acids. There are many cysteines in hair keratins but only a small number in epidermal keratins and rare or none in simple-type keratins. The heads and/or tails of epidermal keratins are glycine and phenylalanine rich but alanine poor, whereas parallel domains of hair keratins are abundant in prolines, and those of simple-type epithelial keratins are enriched in acidic and/or basic residues. The observed differences between simple-type, epidermal and hair keratins are highly conserved throughout evolution. Cysteines and histidines, which are infrequent keratin amino acids, are involved in de novo mutations that are markedly overrepresented in keratins. Hence, keratins have evolutionarily conserved and domain-selectively enriched amino acids including glycine and phenylalanine (epidermal), cysteine and proline (hair), and basic and acidic (simple-type epithelial), which reflect unique functions related to structural flexibility, rigidity and solubility, respectively. Our findings also support the importance of human keratin 'mutation hotspot' residues and their wild-type counterparts.
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Affiliation(s)
- Pavel Strnad
- Department of Internal Medicine I, Center for Internal Medicine, University Medical Center Ulm, Albert-Einstein-Allee 23, D-89081 Ulm, Germany.
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