1
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Goliusova DV, Sharikova MY, Lavrenteva KA, Lebedeva OS, Muranova LK, Gusev NB, Bogomazova AN, Lagarkova MA. Role of Filamin C in Muscle Cells. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:1546-1557. [PMID: 39418514 DOI: 10.1134/s0006297924090025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Revised: 07/02/2024] [Accepted: 08/14/2024] [Indexed: 10/19/2024]
Abstract
Filamin C (FLNC) is a member of a high-molecular weight protein family, which bind actin filaments in the cytoskeleton of various cells. In human genome FLNC is encoded by the FLNC gene located on chromosome 7 and is expressed predominantly in striated skeletal and cardiac muscle cells. Filamin C is involved in organization and stabilization of thin actin filaments three-dimensional network in sarcomeres, and is supposed to play a role of mechanosensor transferring mechanical signals to different protein targets. Under mechanical stress FLNC can undergo unfolding that increases the risk of its aggregation. FLNC molecules with an impaired native structure could be eliminated by the BAG3-mediated chaperone-assisted selective autophagy. Mutations in the FLNC gene could be accompanied by the changes in FLNC interaction with its protein partners and could lead to formation of aggregates, which overload the autophagy and proteasome protein degradation systems, thus facilitating development of various pathological processes. Molecular mechanisms of the FLNC-associated congenital disorders, called filaminopathies, remain poorly understood. This review is devoted to analysis of the structure and mechanisms of filamin C function in muscle and heart cells in normal state and in the FLNC-associated pathologies. The presented data summarize the results of research at the molecular, cellular, and tissue levels and allow us to outline promising ways for further investigation of pathogenetic mechanisms in filaminopathies.
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Affiliation(s)
- Daria V Goliusova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, Federal Medical Biological Agency, Moscow, 119435, Russia.
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Margarita Y Sharikova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, Federal Medical Biological Agency, Moscow, 119435, Russia
| | - Kristina A Lavrenteva
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, Federal Medical Biological Agency, Moscow, 119435, Russia
| | - Olga S Lebedeva
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, Federal Medical Biological Agency, Moscow, 119435, Russia
| | - Lidia K Muranova
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Nikolai B Gusev
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Alexandra N Bogomazova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, Federal Medical Biological Agency, Moscow, 119435, Russia
| | - Maria A Lagarkova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, Federal Medical Biological Agency, Moscow, 119435, Russia
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2
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Wang Y, Yang J, Hu F, Yang Y, Huang K, Zhang K. Cryo-EM reveals how the mastigoneme assembles and responds to environmental signal changes. J Cell Biol 2023; 222:e202301066. [PMID: 37882754 PMCID: PMC10602792 DOI: 10.1083/jcb.202301066] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 08/24/2023] [Accepted: 09/19/2023] [Indexed: 10/27/2023] Open
Abstract
Mastigonemes are thread-like structures adorning the flagella of protists. In Chlamydomonas reinhardtii, filamentous mastigonemes find their roots in the flagella's distal region, associated with the channel protein PKD2, implying their potential contribution to external signal sensing and flagellar motility control. Here, we present the single-particle cryo-electron microscopy structure of the mastigoneme at 3.4 Å. The filament unit, MST1, consists of nine immunoglobulin-like domains and six Sushi domains, trailed by an elastic polyproline-II helix. Our structure demonstrates that MST1 subunits are periodically assembled to form a centrosymmetric, non-polar filament. Intriguingly, numerous clustered disulfide bonds within a ladder-like spiral configuration underscore structural resilience. While defects in the mastigoneme structure did not noticeably affect general attributes of cell swimming, they did impact specific swimming properties, particularly under varied environmental conditions such as redox shifts and heightened viscosity. Our findings illuminate the potential role of mastigonemes in flagellar motility and suggest their involvement in diverse environmental responses.
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Affiliation(s)
- Yue Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Jun Yang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Fangheng Hu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Yuchen Yang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Kaiyao Huang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Kai Zhang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
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3
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Zhang H, Mao Z, Yang Z, Nakamura F. Identification of Filamin A Mechanobinding Partner III: SAV1 Specifically Interacts with Filamin A Mechanosensitive Domain 21. Biochemistry 2023; 62:1197-1208. [PMID: 36857526 DOI: 10.1021/acs.biochem.2c00665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Filamin A (FLNA) cross-links actin filaments and mediates mechanotransduction by force-induced conformational changes of its domains. FLNA's mechanosensitive immunoglobulin-like repeats (R) interact with each other to create cryptic binding sites, which can be exposed by physiologically relevant mechanical forces. Using the FLNA mechanosensing domains as an affinity ligand followed by stable isotope labeling by amino acids in cell culture (SILAC)-based proteomics, we recently identified smoothelin and fimbacin as FLNA mechanobinding proteins. Here, using the mechanosensing domain as an affinity ligand and two labeled amino acids, we identify salvador homologue 1 (SAV1), a component of the Hippo pathway kinase cascade, as a new FLNA mechanobinding partner. We demonstrate that SAV1 specifically interacts with the cryptic C-D cleft of FLNA R21 and map the FLNA-binding site on SAV1. We show that point mutations on the R21 C strand block the SAV1 interaction and find that SAV1 contains a FLNA-binding motif in the central region (116Phe-124Val). Point mutations F116A and T118A (FT/AA) disrupt the interaction. A proximity ligation assay reveals that their interaction occurs in the cytosol in an actin polymerization-dependent manner. Although SAV1 is typically found in the cytosol, disrupting the interaction between SAV1 and FLNA causes SAV1 to diffuse to the nucleus and YAP1 to diffuse to the cytosol in an inverse relationship. These results suggest that FLNA mediates regulation of the Hippo pathway through actin polymerization-dependent interaction with SAV1.
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Affiliation(s)
- Huaguan Zhang
- School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Zhenfeng Mao
- School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Ziwei Yang
- School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Fumihiko Nakamura
- School of Pharmaceutical Science and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
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Feng Z, Mao Z, Yang Z, Liu X, Nakamura F. The force-dependent filamin A-G3BP1 interaction regulates phase-separated stress granule formation. J Cell Sci 2023; 136:297259. [PMID: 36806943 DOI: 10.1242/jcs.260684] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 02/03/2023] [Indexed: 02/22/2023] Open
Abstract
Filamin A (FLNA) is an actin crosslinking protein that mediates mechanotransduction. External and internal mechanical forces, through the actin cytoskeleton, can induce conformational changes of the FLNA molecule to expose cryptic binding sites for its binding partners. Here, we identified Ras GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) as a new FLNA mechanobinding partner. Unlike other FLNA binding partners to the mechanosensing domain repeat 21 (R21), G3BP1 requires an additional neighboring repeat R22 to interact. We demonstrated that their interaction occurs in the cytosol of living cells in an actin polymerization-dependent manner. We also mapped the FLNA-binding site on G3BP1 and found that a F360A point mutation in the RNA recognition motif disrupts the interaction. RNA interfered with the FLNA-G3BP1 interaction, and FLNA did not localize in RNA-rich stress granules (SGs). Disruption of the interaction was sufficient to promote phase-separated SG formation, and arsenite treatment further stimulated the formation of SGs. Taken together, these data identify G3BP1 as a new mechanobinding protein that interacts with the FLNA mechanosensing domain R21 and suggest that SG formation is partially regulated by mechanical force.
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Affiliation(s)
- Ziyi Feng
- School of Pharmaceutical Science and Technology, Life Science Platform, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, 300072, China
| | - Zhenfeng Mao
- School of Pharmaceutical Science and Technology, Life Science Platform, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, 300072, China
| | - Ziwei Yang
- School of Pharmaceutical Science and Technology, Life Science Platform, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, 300072, China
| | - Xiaowei Liu
- School of Pharmaceutical Science and Technology, Life Science Platform, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, 300072, China
| | - Fumihiko Nakamura
- School of Pharmaceutical Science and Technology, Life Science Platform, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, 300072, China
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5
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Beedle AEM, Garcia-Manyes S. The role of single protein elasticity in mechanobiology. NATURE REVIEWS. MATERIALS 2023; 8:10-24. [PMID: 37469679 PMCID: PMC7614781 DOI: 10.1038/s41578-022-00488-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/07/2022] [Indexed: 07/21/2023]
Abstract
In addition to biochemical signals and genetic considerations, mechanical forces are rapidly emerging as a master regulator of human physiology. Yet the molecular mechanisms that regulate force-induced functionalities across a wide range of scales, encompassing the cell, tissue or organ levels, are comparatively not so well understood. With the advent, development and refining of single molecule nanomechanical techniques, enabling to exquisitely probe the conformational dynamics of individual proteins under the effect of a calibrated force, we have begun to acquire a comprehensive knowledge on the rich plethora of physicochemical principles that regulate the elasticity of single proteins. Here we review the major advances underpinning our current understanding of how the elasticity of single proteins regulates mechanosensing and mechanotransduction. We discuss the present limitations and future challenges of such a prolific and burgeoning field.
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Affiliation(s)
- Amy EM Beedle
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
- Institute for Bioengineering of Catalonia (IBEC), the Barcelona Institute of Technology (BIST), 08028 Barcelona, Spain
| | - Sergi Garcia-Manyes
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King’s College London, Strand, WC2R 2LS London, United Kingdom
- Single Molecule Mechanobiology Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, London, UK
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6
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Mao Z, Nakamura F. Interaction of LARP4 to filamin A mechanosensing domain regulates cell migrations. Front Cell Dev Biol 2023; 11:1152109. [PMID: 37169020 PMCID: PMC10164935 DOI: 10.3389/fcell.2023.1152109] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 04/14/2023] [Indexed: 05/13/2023] Open
Abstract
Filamin A (FLNA) is an actin cross-linking protein that mediates mechanotransduction. Force-dependent conformational changes of FLNA molecule expose cryptic binding site of FLNA, allowing interaction with partners such as integrin, smoothelin, and fimbacin. Here, we identified La-related protein 4 (LARP4) as a new FLNA mechanobinding partner. LARP4 specifically interacts with the cleft formed by C and D strands of immunoglobulin-like repeat 21 (R21) which is blocked by A strand of R20 without force. We validated the interaction between LARP4 and FLNA R21 both in vivo and in vitro. We also determined the critical amino acid that is responsible for the interaction and generated the non-FLNA-binding mutant LARP4 (F277A in human: F273A in mouse Larp4) that disrupts the interaction. Fluorescence recovery after photobleaching (FRAP) of GFP-labeled LARP4 in living cells demonstrated that mutant LARP4 diffuses faster than WT LARP4. Proximity ligation assay (PLA) also confirmed their interaction and disruption of actin polymerization diminishes the interaction. Data mining of RNAseq analysis of LARP4 knockdown (KD) HEK293T cells suggested that LARP4 is involved in morphogenesis and cell motility. Consistent with this prediction, we found that KD of LARP4 increases cell migration speed and expression of the F277A mutant LARP4 in LARP4-KD cells also leads to a higher cell migration speed compared to WT LARP4. These results demonstrated that the LARP4 interaction with FLNA regulates cell migration.
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7
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Vakhrusheva A, Murashko A, Trifonova E, Efremov Y, Timashev P, Sokolova O. Role of Actin-binding Proteins in the Regulation of Cellular Mechanics. Eur J Cell Biol 2022; 101:151241. [DOI: 10.1016/j.ejcb.2022.151241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 04/18/2022] [Accepted: 05/19/2022] [Indexed: 12/25/2022] Open
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8
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Application of piconewton forces to individual filopodia reveals mechanosensory role of L-type Ca 2+ channels. Biomaterials 2022; 284:121477. [PMID: 35395455 DOI: 10.1016/j.biomaterials.2022.121477] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 03/18/2022] [Indexed: 11/02/2022]
Abstract
Filopodia are ubiquitous membrane projections that play crucial role in guiding cell migration on rigid substrates and through extracellular matrix by utilizing yet unknown mechanosensing molecular pathways. As recent studies show that Ca2+ channels localized to filopodia play an important role in regulation of their formation and since some Ca2+ channels are known to be mechanosensitive, force-dependent activity of filopodial Ca2+ channels might be linked to filopodia's mechanosensing function. We tested this hypothesis by monitoring changes in the intra-filopodial Ca2+ level in response to application of stretching force to individual filopodia of several cell types using optical tweezers. Results show that stretching forces of tens of pN strongly promote Ca2+ influx into filopodia, causing persistent Ca2+ oscillations that last for minutes even after the force is released. Several known mechanosensitive Ca2+ channels, such as Piezo 1, Piezo 2 and TRPV4, were found to be dispensable for the observed force-dependent Ca2+ influx, while L-type Ca2+ channels appear to be a key player in the discovered phenomenon. As previous studies have shown that intra-filopodial transient Ca2+ signals play an important role in guidance of cell migration, our results suggest that the force-dependent activation of L-type Ca2+ channels may contribute to this process. Overall, our study reveals an intricate interplay between mechanical forces and Ca2+ signaling in filopodia, providing novel mechanistic insights for the force-dependent filopodia functions in guidance of cell migration.
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9
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Greiten JK, Kliewe F, Schnarre A, Artelt N, Schröder S, Rogge H, Amann K, Daniel C, Lindenmeyer MT, Cohen CD, Endlich K, Endlich N. The role of filamins in mechanically stressed podocytes. FASEB J 2021; 35:e21560. [PMID: 33860543 DOI: 10.1096/fj.202001179rr] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 02/26/2021] [Accepted: 03/15/2021] [Indexed: 11/11/2022]
Abstract
Glomerular hypertension induces mechanical load to podocytes, often resulting in podocyte detachment and the development of glomerulosclerosis. Although it is well known that podocytes are mechanosensitive, the mechanosensors and mechanotransducers are still unknown. Since filamin A, an actin-binding protein, is already described to be a mechanosensor and mechanotransducer, we hypothesized that filamins could be important for the outside-in signaling as well as the actin cytoskeleton of podocytes under mechanical stress. In this study, we demonstrate that filamin A is the main isoform of the filamin family that is expressed in cultured podocytes. Together with filamin B, filamin A was significantly up-regulated during mechanical stretch (3 days, 0.5 Hz, and 5% extension). To study the role of filamin A in cultured podocytes under mechanical stress, filamin A was knocked down (Flna KD) by specific siRNA. Additionally, we established a filamin A knockout podocyte cell line (Flna KO) by CRISPR/Cas9. Knockdown and knockout of filamin A influenced the expression of synaptopodin, a podocyte-specific protein, focal adhesions as well as the morphology of the actin cytoskeleton. Moreover, the cell motility of Flna KO podocytes was significantly increased. Since the knockout of filamin A has had no effect on cell adhesion of podocytes during mechanical stress, we simultaneously knocked down the expression of filamin A and B. Thereby, we observed a significant loss of podocytes during mechanical stress indicating a compensatory mechanism. Analyzing hypertensive mice kidneys as well as biopsies of patients suffering from diabetic nephropathy, we found an up-regulation of filamin A in podocytes in contrast to the control. In summary, filamin A and B mediate matrix-actin cytoskeleton interactions which are essential for the adaptation of cultured podocyte to mechanical stress.
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Affiliation(s)
- Jonas K Greiten
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Felix Kliewe
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Annabel Schnarre
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Nadine Artelt
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Sindy Schröder
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Henrik Rogge
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Kerstin Amann
- Department of Nephropathology, Friedrich-Alexander University (FAU) Erlangen-Nuremberg, Erlangen, Germany
| | - Christoph Daniel
- Department of Nephropathology, Friedrich-Alexander University (FAU) Erlangen-Nuremberg, Erlangen, Germany
| | - Maja T Lindenmeyer
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Clemens D Cohen
- Nephrological Center, Medical Clinic and Policlinic IV, University of Munich, Munich, Germany
| | - Karlhans Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Nicole Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
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10
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The Role of Z-disc Proteins in Myopathy and Cardiomyopathy. Int J Mol Sci 2021; 22:ijms22063058. [PMID: 33802723 PMCID: PMC8002584 DOI: 10.3390/ijms22063058] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/07/2021] [Accepted: 03/11/2021] [Indexed: 12/11/2022] Open
Abstract
The Z-disc acts as a protein-rich structure to tether thin filament in the contractile units, the sarcomeres, of striated muscle cells. Proteins found in the Z-disc are integral for maintaining the architecture of the sarcomere. They also enable it to function as a (bio-mechanical) signalling hub. Numerous proteins interact in the Z-disc to facilitate force transduction and intracellular signalling in both cardiac and skeletal muscle. This review will focus on six key Z-disc proteins: α-actinin 2, filamin C, myopalladin, myotilin, telethonin and Z-disc alternatively spliced PDZ-motif (ZASP), which have all been linked to myopathies and cardiomyopathies. We will summarise pathogenic variants identified in the six genes coding for these proteins and look at their involvement in myopathy and cardiomyopathy. Listing the Minor Allele Frequency (MAF) of these variants in the Genome Aggregation Database (GnomAD) version 3.1 will help to critically re-evaluate pathogenicity based on variant frequency in normal population cohorts.
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11
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Grexa I, Fekete T, Molnár J, Molnár K, Vizsnyiczai G, Ormos P, Kelemen L. Single-Cell Elasticity Measurement with an Optically Actuated Microrobot. MICROMACHINES 2020; 11:mi11090882. [PMID: 32972024 PMCID: PMC7570390 DOI: 10.3390/mi11090882] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/15/2020] [Accepted: 09/20/2020] [Indexed: 02/07/2023]
Abstract
A cell elasticity measurement method is introduced that uses polymer microtools actuated by holographic optical tweezers. The microtools were prepared with two-photon polymerization. Their shape enables the approach of the cells in any lateral direction. In the presented case, endothelial cells grown on vertical polymer walls were probed by the tools in a lateral direction. The use of specially shaped microtools prevents the target cells from photodamage that may arise during optical trapping. The position of the tools was recorded simply with video microscopy and analyzed with image processing methods. We critically compare the resulting Young’s modulus values to those in the literature obtained by other methods. The application of optical tweezers extends the force range available for cell indentations measurements down to the fN regime. Our approach demonstrates a feasible alternative to the usual vertical indentation experiments.
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Affiliation(s)
- István Grexa
- Biological Research Centre, Temesvári krt. 62, 6726 Szeged, Hungary; (I.G.); (T.F.); (J.M.); (K.M.); (G.V.); (P.O.)
- Doctoral School of Interdisciplinary Medicine, University of Szeged, Korányi fasor 10, 6720 Szeged, Hungary
| | - Tamás Fekete
- Biological Research Centre, Temesvári krt. 62, 6726 Szeged, Hungary; (I.G.); (T.F.); (J.M.); (K.M.); (G.V.); (P.O.)
- Doctoral School of Multidisciplinary Medicine, Dóm tér 9, Hungary University of Szeged, 6720 Szeged, Hungary
| | - Judit Molnár
- Biological Research Centre, Temesvári krt. 62, 6726 Szeged, Hungary; (I.G.); (T.F.); (J.M.); (K.M.); (G.V.); (P.O.)
| | - Kinga Molnár
- Biological Research Centre, Temesvári krt. 62, 6726 Szeged, Hungary; (I.G.); (T.F.); (J.M.); (K.M.); (G.V.); (P.O.)
- Doctoral School of Theoretical Medicine, University of Szeged, Korányi fasor 10, 6720 Szeged, Hungary
| | - Gaszton Vizsnyiczai
- Biological Research Centre, Temesvári krt. 62, 6726 Szeged, Hungary; (I.G.); (T.F.); (J.M.); (K.M.); (G.V.); (P.O.)
| | - Pál Ormos
- Biological Research Centre, Temesvári krt. 62, 6726 Szeged, Hungary; (I.G.); (T.F.); (J.M.); (K.M.); (G.V.); (P.O.)
| | - Lóránd Kelemen
- Biological Research Centre, Temesvári krt. 62, 6726 Szeged, Hungary; (I.G.); (T.F.); (J.M.); (K.M.); (G.V.); (P.O.)
- Correspondence: ; Tel.: +36-62-599-600 (ext. 419)
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12
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Benedito M, Manca F, Palla PL, Giordano S. Rate-dependent force-extension models for single-molecule force spectroscopy experiments. Phys Biol 2020; 17:056002. [PMID: 32464604 DOI: 10.1088/1478-3975/ab97a8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Single-molecule force spectroscopy techniques allow for the measurement of several static and dynamic features of macromolecules of biological origin. In particular, atomic force microscopy, used with a variable pulling rate, provides valuable information on the folding/unfolding dynamics of proteins. We propose here two different models able to describe the out-of-equilibrium statistical mechanics of a chain composed of bistable units. These latter represent the protein domains, which can be either folded or unfolded. Both models are based on the Langevin approach and their implementation allows for investigating the effect of the pulling rate and of the device intrinsic elasticity on the chain unfolding response. The theoretical results (both analytical and numerical) have been compared with experimental data concerning the unfolding of the titin and filamin proteins, eventually obtaining a good agreement over a large range of the pulling rates.
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Affiliation(s)
- Manon Benedito
- Institute of Electronics, Microelectronics and Nanotechnology, UMR 8520, Univ. Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, LIA LICS/LEMAC, 59000 Lille, France
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13
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Structure and Function of Filamin C in the Muscle Z-Disc. Int J Mol Sci 2020; 21:ijms21082696. [PMID: 32295012 PMCID: PMC7216277 DOI: 10.3390/ijms21082696] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 12/22/2022] Open
Abstract
Filamin C (FLNC) is one of three filamin proteins (Filamin A (FLNA), Filamin B (FLNB), and FLNC) that cross-link actin filaments and interact with numerous binding partners. FLNC consists of a N-terminal actin-binding domain followed by 24 immunoglobulin-like repeats with two intervening calpain-sensitive hinges separating R15 and R16 (hinge 1) and R23 and R24 (hinge-2). The FLNC subunit is dimerized through R24 and calpain cleaves off the dimerization domain to regulate mobility of the FLNC subunit. FLNC is localized in the Z-disc due to the unique insertion of 82 amino acid residues in repeat 20 and necessary for normal Z-disc formation that connect sarcomeres. Since phosphorylation of FLNC by PKC diminishes the calpain sensitivity, assembly, and disassembly of the Z-disc may be regulated by phosphorylation of FLNC. Mutations of FLNC result in cardiomyopathy and muscle weakness. Although this review will focus on the current understanding of FLNC structure and functions in muscle, we will also discuss other filamins because they share high sequence similarity and are better characterized. We will also discuss a possible role of FLNC as a mechanosensor during muscle contraction.
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14
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Iqbal NS, Jascur TA, Harrison SM, Edwards AB, Smith LT, Choi ES, Arevalo MK, Chen C, Zhang S, Kern AJ, Scheuerle AE, Sanchez EJ, Xing C, Baker LA. Prune belly syndrome in surviving males can be caused by Hemizygous missense mutations in the X-linked Filamin A gene. BMC MEDICAL GENETICS 2020; 21:38. [PMID: 32085749 PMCID: PMC7035669 DOI: 10.1186/s12881-020-0973-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 02/12/2020] [Indexed: 12/12/2022]
Abstract
Background Prune belly syndrome (PBS) is a rare, multi-system congenital myopathy primarily affecting males that is poorly described genetically. Phenotypically, its morbidity spans from mild to lethal, however, all isolated PBS cases manifest three cardinal pathological features: 1) wrinkled flaccid ventral abdominal wall with skeletal muscle deficiency, 2) urinary tract dilation with poorly contractile smooth muscle, and 3) intra-abdominal undescended testes. Despite evidence for a genetic basis, previously reported PBS autosomal candidate genes only account for one consanguineous family and single cases. Methods We performed whole exome sequencing (WES) of two maternal adult half-brothers with syndromic PBS (PBS + Otopalatodigital spectrum disorder [OPDSD]) and two unrelated sporadic individuals with isolated PBS and further functionally validated the identified mutations. Results We identified three unreported hemizygous missense point mutations in the X-chromosome gene Filamin A (FLNA) (c.4952 C > T (p.A1448V), c.6727C > T (p.C2160R), c.5966 G > A (p.G2236E)) in two related cases and two unrelated sporadic individuals. Two of the three PBS mutations map to the highly regulatory, stretch-sensing Ig19–21 region of FLNA and enhance binding to intracellular tails of the transmembrane receptor β-integrin 1 (ITGβ1). Conclusions FLNA is a regulatory actin-crosslinking protein that functions in smooth muscle cells as a mechanosensing molecular scaffold, transmitting force signals from the actin-myosin motor units and cytoskeleton via binding partners to the extracellular matrix. This is the first evidence for an X-linked cause of PBS in multiple unrelated individuals and expands the phenotypic spectrum associated with FLNA in males surviving even into adulthood.
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Affiliation(s)
- Nida S Iqbal
- Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA.
| | - Thomas A Jascur
- Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Steven M Harrison
- Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Angelena B Edwards
- Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Luke T Smith
- Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Erin S Choi
- Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Michelle K Arevalo
- Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Catherine Chen
- Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Shaohua Zhang
- Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Adam J Kern
- Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Angela E Scheuerle
- Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA.,McDermott Center for Human Growth and Development, Department of Bioinformatics, Department of Clinical Sciences, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Emma J Sanchez
- Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA.,Children's Health Dallas, 2350 N. Stemmons Freeway, Suite F4300, Dallas, TX, 75207, USA
| | - Chao Xing
- McDermott Center for Human Growth and Development, Department of Bioinformatics, Department of Clinical Sciences, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Linda A Baker
- Department of Urology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA. .,Children's Health Dallas, 2350 N. Stemmons Freeway, Suite F4300, Dallas, TX, 75207, USA.
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15
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Multiplexed protein force spectroscopy reveals equilibrium protein folding dynamics and the low-force response of von Willebrand factor. Proc Natl Acad Sci U S A 2019; 116:18798-18807. [PMID: 31462494 PMCID: PMC6754583 DOI: 10.1073/pnas.1901794116] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Single-molecule force spectroscopy has provided unprecedented insights into protein folding, force regulation, and function. So far, the field has relied primarily on atomic force microscope and optical tweezers assays that, while powerful, are limited in force resolution, throughput, and require feedback for constant force measurements. Here, we present a modular approach based on magnetic tweezers (MT) for highly multiplexed protein force spectroscopy. Our approach uses elastin-like polypeptide linkers for the specific attachment of proteins, requiring only short peptide tags on the protein of interest. The assay extends protein force spectroscopy into the low force (<1 pN) regime and enables parallel and ultra-stable measurements at constant forces. We present unfolding and refolding data for the small, single-domain protein ddFLN4, commonly used as a molecular fingerprint in force spectroscopy, and for the large, multidomain dimeric protein von Willebrand factor (VWF) that is critically involved in primary hemostasis. For both proteins, our measurements reveal exponential force dependencies of unfolding and refolding rates. We directly resolve the stabilization of the VWF A2 domain by Ca2+ and discover transitions in the VWF C domain stem at low forces that likely constitute the first steps of VWF's mechano-activation. Probing the force-dependent lifetime of biotin-streptavidin bonds, we find that monovalent streptavidin constructs with specific attachment geometry are significantly more force stable than commercial, multivalent streptavidin. We expect our modular approach to enable multiplexed force-spectroscopy measurements for a wide range of proteins, in particular in the physiologically relevant low-force regime.
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16
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Mechanical unfolding of spectrin reveals a super-exponential dependence of unfolding rate on force. Sci Rep 2019; 9:11101. [PMID: 31366931 PMCID: PMC6668576 DOI: 10.1038/s41598-019-46525-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 06/18/2019] [Indexed: 11/12/2022] Open
Abstract
We investigated the mechanical unfolding of single spectrin molecules over a broad range of loading rates and thus unfolding forces by combining magnetic tweezers with atomic force microscopy. We find that the mean unfolding force increases logarithmically with loading rate at low loading rates, but the increase slows at loading rates above 1pN/s. This behavior indicates an unfolding rate that increases exponentially with the applied force at low forces, as expected on the basis of one-dimensional models of protein unfolding. At higher forces, however, the increase of the unfolding rate with the force becomes faster than exponential, which may indicate anti-Hammond behavior where the structures of the folded and transition states become more different as their free energies become more similar. Such behavior is rarely observed and can be explained by either a change in the unfolding pathway or as a reflection of a multidimensional energy landscape of proteins under force.
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17
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Wang J, Nakamura F. Identification of Filamin A Mechanobinding Partner II: Fimbacin Is a Novel Actin Cross-Linking and Filamin A Binding Protein. Biochemistry 2019; 58:4737-4743. [PMID: 30990684 DOI: 10.1021/acs.biochem.9b00101] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Filamin A (FLNA), an actin cross-linking protein, acts as a mechanosensor and mechanotransducer by exposing the cryptic binding site on repeat 21 (R21) to interact with integrin. Here, we investigated if any other biological molecule interacts with the cryptic binding site. Using proteomics and an in silico screening for a FLNA-binding motif, we identified and characterized a protein termed fimbacin (filamin mechanobinding actin cross-linking protein), encoded in the LUZP1 gene, as a novel FLNA-binding partner. Fimbacin does not interact with canonical full-length FLNA, but the exposure of a cryptic integrin-binding site of FLNA R21 enables fimbacin to interact. We have identified two FLNA binding sites on fimbacin and determined critical amino acid residues for the interaction. We also found that fimbacin itself is a new actin cross-linking protein and mapped the actin-binding site on amino acid residues 400-500. Fimbacin oligomerizes (estimated as an octamer on size exclusion chromatography) through the amino-terminal domain that is predicted to be a coiled-coil to cross-link actin filaments. When expressed, fimbacin localized to actin stress fibers in tissue culture cells. Although the interaction with FLNA is not necessary for fimbacin to colocalize with F-actin, fluorescent recovery after photobleaching (FRAP) revealed that their interaction stabilizes fimbacin on the actin cytoskeleton and that inhibition of Rho-kinase, an upstream activator of myosin II, also decreases the interaction presumably due to a loss of internal mechanical stress. Taken together, these data identify fimbacin as a new actin cross-linking protein that interacts with the FLNA mechanosensing domain R21.
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Affiliation(s)
- Jiale Wang
- School of Pharmaceutical Science and Technology, Life Science Platform , Tianjin University , 92 Weijin Road, Nankai District , Tianjin , 300072 , China
| | - Fumihiko Nakamura
- School of Pharmaceutical Science and Technology, Life Science Platform , Tianjin University , 92 Weijin Road, Nankai District , Tianjin , 300072 , China
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18
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Wang L, Nakamura F. Identification of Filamin A Mechanobinding Partner I: Smoothelin Specifically Interacts with the Filamin A Mechanosensitive Domain 21. Biochemistry 2019; 58:4726-4736. [PMID: 30990690 DOI: 10.1021/acs.biochem.9b00100] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Filamin A (FLNA) is a ubiquitously expressed actin cross-linking protein and a scaffold of numerous binding partners to regulate cell proliferation, migration, and survival. FLNA is a homodimer, and each subunit has an N-terminal actin-binding domain followed by 24 immunoglobulin-like repeats (R). FLNA mediates mechanotransduction by force-induced conformational changes of its cryptic integrin-binding site on R21. Here, we identified two novel FLNA-binding partners, smoothelins (SMTN A and B) and leucine zipper protein 1 (LUZP1), using stable isotope labeling by amino acids in cell culture (SILAC)-based proteomics followed by an in silico screening for proteins having a consensus FLNA-binding domain. We found that, although SMTN does not interact with full-length FLNA, it binds to FLNA variant 1 (FLNAvar-1) that exposes the cryptic CD cleft of R21. Point mutations on the C strand that disrupt the integrin binding also block the SMTN interaction. We identified FLNA-binding domains on SMTN using mutagenesis and used the mutant SMTN to investigate the role of the FLNA-SMTN interaction on the dynamics and localization of SMTN in living cells. Fluorescence recovery after photobleaching (FRAP) of GFP-labeled SMTN in living cells demonstrated that the non-FLNA-binding mutant SMTN diffuses faster than wild-type SMTN. Moreover, inhibition of Rho-kinase using Y27632 also increases the diffusion. These data demonstrated that SMTN specifically interacts with FLNAvar-1 and mechanically activated FLNA in cells. The companion report (Wang and Nakamura, 2019) describes the interactions of FLNA with the transcript of the LUZP1 gene.
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Affiliation(s)
- Lina Wang
- School of Pharmaceutical Science and Technology, Life Science Platform , Tianjin University , 92 Weijin Road , Nankai District, Tianjin 300072 , China
| | - Fumihiko Nakamura
- School of Pharmaceutical Science and Technology, Life Science Platform , Tianjin University , 92 Weijin Road , Nankai District, Tianjin 300072 , China
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19
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Ehsan M, Jiang H, L Thomson K, Gehmlich K. When signalling goes wrong: pathogenic variants in structural and signalling proteins causing cardiomyopathies. J Muscle Res Cell Motil 2017; 38:303-316. [PMID: 29119312 PMCID: PMC5742121 DOI: 10.1007/s10974-017-9487-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/28/2017] [Indexed: 12/20/2022]
Abstract
Cardiomyopathies are a diverse group of cardiac disorders with distinct phenotypes, depending on the proteins and pathways affected. A substantial proportion of cardiomyopathies are inherited and those will be the focus of this review article. With the wide application of high-throughput sequencing in the practice of clinical genetics, the roles of novel genes in cardiomyopathies are recognised. Here, we focus on a subgroup of cardiomyopathy genes [TTN, FHL1, CSRP3, FLNC and PLN, coding for Titin, Four and a Half LIM domain 1, Muscle LIM Protein, Filamin C and Phospholamban, respectively], which, despite their diverse biological functions, all have important signalling functions in the heart, suggesting that disturbances in signalling networks can contribute to cardiomyopathies.
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Affiliation(s)
- Mehroz Ehsan
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - He Jiang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Kate L Thomson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK.
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20
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Zhao X, Zeng X, Lu C, Yan J. Studying the mechanical responses of proteins using magnetic tweezers. NANOTECHNOLOGY 2017; 28:414002. [PMID: 28766506 DOI: 10.1088/1361-6528/aa837e] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The mechanical stability of proteins has been extensively studied using AFM as a single-molecule force spectroscopy method. While this has led to many important results, these studies have been mainly limited to fast unfolding at a high-force regime due to the rapid mechanical drift in most AFM stretching experiments. Therefore, there is a gap between the knowledge obtained at a high-force regime and the mechanical properties of proteins at a lower force regime which is often more physiologically relevant. Recent studies have demonstrated that this gap can be addressed by stretching single protein molecules using magnetic tweezers, due to the excellent mechanical stability this technology offers. Here we review magnetic tweezers technology and its current application in studies of the force-dependent stability and interactions of proteins.
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Affiliation(s)
- Xiaodan Zhao
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, 117411, Singapore
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21
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Winardhi RS, Tang Q, Chen J, Yao M, Yan J. Probing Small Molecule Binding to Unfolded Polyprotein Based on its Elasticity and Refolding. Biophys J 2017; 111:2349-2357. [PMID: 27926836 DOI: 10.1016/j.bpj.2016.10.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 09/21/2016] [Accepted: 10/24/2016] [Indexed: 10/20/2022] Open
Abstract
Unfolded protein, a disordered structure found before folding of newly synthesized protein or after protein denaturation, is a substrate for binding by many cellular factors such as heat-stable proteins, chaperones, and many small molecules. However, it is challenging to directly probe such interactions in physiological solution conditions because proteins are largely in their folded state. In this work we probed small molecule binding to mechanically unfolded polyprotein using sodium dodecyl sulfate (SDS) as an example. The effect of binding is quantified based on changes in the elasticity and refolding of the unfolded polyprotein in the presence of SDS. We show that this single-molecule mechanical detection of binding to unfolded polyprotein can serve, to our knowledge, as a novel label-free assay with a great potential to study many factors that interact with unfolded protein domains, which underlie many important biological processes.
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Affiliation(s)
- Ricksen S Winardhi
- Department of Physics, National University of Singapore, Singapore, Singapore; Mechanobiology Institute, National University of Singapore, Singapore, Singapore; Centre for Bioimaging Sciences, National University of Singapore, Singapore, Singapore
| | - Qingnan Tang
- Department of Physics, National University of Singapore, Singapore, Singapore; Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Jin Chen
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Mingxi Yao
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Jie Yan
- Department of Physics, National University of Singapore, Singapore, Singapore; Mechanobiology Institute, National University of Singapore, Singapore, Singapore; Centre for Bioimaging Sciences, National University of Singapore, Singapore, Singapore.
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22
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Hu X, Margadant FM, Yao M, Sheetz MP. Molecular stretching modulates mechanosensing pathways. Protein Sci 2017; 26:1337-1351. [PMID: 28474792 DOI: 10.1002/pro.3188] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/26/2017] [Accepted: 04/27/2017] [Indexed: 01/21/2023]
Abstract
For individual cells in tissues to create the diverse forms of biological organisms, it is necessary that they must reliably sense and generate the correct forces over the correct distances and directions. There is considerable evidence that the mechanical aspects of the cellular microenvironment provide critical physical parameters to be sensed. How proteins sense forces and cellular geometry to create the correct morphology is not understood in detail but protein unfolding appears to be a major component in force and displacement sensing. Thus, the crystallographic structure of a protein domain provides only a starting point to then analyze what will be the effects of physiological forces through domain unfolding or catch-bond formation. In this review, we will discuss the recent studies of cytoskeletal and adhesion proteins that describe protein domain dynamics. Forces applied to proteins can activate or inhibit enzymes, increase or decrease protein-protein interactions, activate or inhibit protein substrates, induce catch bonds and regulate interactions with membranes or nucleic acids. Further, the dynamics of stretch-relaxation can average forces or movements to reliably regulate morphogenic movements. In the few cases where single molecule mechanics are studied under physiological conditions such as titin and talin, there are rapid cycles of stretch-relaxation that produce mechanosensing signals. Fortunately, the development of new single molecule and super-resolution imaging methods enable the analysis of single molecule mechanics in physiologically relevant conditions. Thus, we feel that stereotypical changes in cell and tissue shape involve mechanosensing that can be analyzed at the nanometer level to determine the molecular mechanisms involved.
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Affiliation(s)
- Xian Hu
- Mechanobiology Institute, National University of Singapore, Singapore, 117411.,Department of Biosciences, University of Oslo, Oslo, 0316, Norway
| | | | - Mingxi Yao
- Mechanobiology Institute, National University of Singapore, Singapore, 117411
| | - Michael Patrick Sheetz
- Mechanobiology Institute, National University of Singapore, Singapore, 117411.,Department of Biological Sciences, University of Columbia, New York, 10027
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23
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Comrie WA, Burkhardt JK. Action and Traction: Cytoskeletal Control of Receptor Triggering at the Immunological Synapse. Front Immunol 2016; 7:68. [PMID: 27014258 PMCID: PMC4779853 DOI: 10.3389/fimmu.2016.00068] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 02/12/2016] [Indexed: 01/03/2023] Open
Abstract
It is well known that F-actin dynamics drive the micron-scale cell shape changes required for migration and immunological synapse (IS) formation. In addition, recent evidence points to a more intimate role for the actin cytoskeleton in promoting T cell activation. Mechanotransduction, the conversion of mechanical input into intracellular biochemical changes, is thought to play a critical role in several aspects of immunoreceptor triggering and downstream signal transduction. Multiple molecules associated with signaling events at the IS have been shown to respond to physical force, including the TCR, costimulatory molecules, adhesion molecules, and several downstream adapters. In at least some cases, it is clear that the relevant forces are exerted by dynamics of the T cell actomyosin cytoskeleton. Interestingly, there is evidence that the cytoskeleton of the antigen-presenting cell also plays an active role in T cell activation, by countering the molecular forces exerted by the T cell at the IS. Since actin polymerization is itself driven by TCR and costimulatory signaling pathways, a complex relationship exists between actin dynamics and receptor activation. This review will focus on recent advances in our understanding of the mechanosensitive aspects of T cell activation, paying specific attention to how F-actin-directed forces applied from both sides of the IS fit into current models of receptor triggering and activation.
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Affiliation(s)
- William A Comrie
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania , Philadelphia, PA , USA
| | - Janis K Burkhardt
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania , Philadelphia, PA , USA
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24
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Abstract
Mechanical stimuli are known to be potent regulators of the form and function of cells and organisms. Although biological regulation has classically been understood in terms of principles from solution biochemistry, advancements in many fields have led to the development of a suite of techniques that are able to reveal the interplay between mechanical loading and changes in the biochemical properties of proteins in systems ranging from single molecules to living organisms. Here, we review these techniques and highlight the emergence of a new molecular-scale understanding of the mechanisms mediating the detection and response of cells to mechanical stimuli, a process termed mechanotransduction. Specifically, we focus on the role of subcellular adhesion structures in sensing the stiffness of the surrounding environment because this process is pertinent to applications in tissue engineering as well the onset of several mechanosensitive disease states, including cancer.
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Affiliation(s)
- Andrew S LaCroix
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708;
| | - Katheryn E Rothenberg
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708;
| | - Brenton D Hoffman
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708;
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25
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Seppälä J, Tossavainen H, Rodic N, Permi P, Pentikäinen U, Ylänne J. Flexible Structure of Peptide-Bound Filamin A Mechanosensor Domain Pair 20-21. PLoS One 2015; 10:e0136969. [PMID: 26322797 PMCID: PMC4554727 DOI: 10.1371/journal.pone.0136969] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 08/12/2015] [Indexed: 11/18/2022] Open
Abstract
Filamins (FLNs) are large, multidomain actin cross-linking proteins with diverse functions. Besides regulating the actin cytoskeleton, they serve as important links between the extracellular matrix and the cytoskeleton by binding cell surface receptors, functioning as scaffolds for signaling proteins, and binding several other cytoskeletal proteins that regulate cell adhesion dynamics. Structurally, FLNs are formed of an amino terminal actin-binding domain followed by 24 immunoglobulin-like domains (IgFLNs). Recent studies have demonstrated that myosin-mediated contractile forces can reveal hidden protein binding sites in the domain pairs IgFLNa18–19 and 20–21, enabling FLNs to transduce mechanical signals in cells. The atomic structures of these mechanosensor domain pairs in the resting state are known, as well as the structures of individual IgFLN21 with ligand peptides. However, little experimental data is available on how interacting protein binding deforms the domain pair structures. Here, using small-angle x-ray scattering-based modelling, x-ray crystallography, and NMR, we show that the adaptor protein migfilin-derived peptide-bound structure of IgFLNa20–21 is flexible and adopts distinctive conformations depending on the presence or absence of the interacting peptide. The conformational changes reported here may be common for all peptides and may play a role in the mechanosensor function of the site.
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Affiliation(s)
- Jonne Seppälä
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
- * E-mail:
| | - Helena Tossavainen
- Program in Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Nebojsa Rodic
- Program in Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Perttu Permi
- Program in Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Ulla Pentikäinen
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Jari Ylänne
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
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26
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Le S, Liu R, Lim CT, Yan J. Uncovering mechanosensing mechanisms at the single protein level using magnetic tweezers. Methods 2015; 94:13-8. [PMID: 26318089 DOI: 10.1016/j.ymeth.2015.08.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 08/01/2015] [Accepted: 08/25/2015] [Indexed: 11/28/2022] Open
Abstract
Mechanosensing of the micro-environments has been shown to be essential for cell survival, growth, differentiation and migration. The mechanosensing pathways are mediated by a set of mechanosensitive proteins located at focal adhesion and cell-cell adherens junctions as well as in the cytoskeleton network. Here we review the applications of magnetic tweezers on elucidating the molecular mechanisms of the mechanosensing proteins. The scope of this review includes the principles of the magnetic tweezers technology, theoretical analysis of force-dependent stability and interaction of mechanosensing proteins, and recent findings obtained using magnetic tweezers.
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Affiliation(s)
- Shimin Le
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore; Department of Physics, National University of Singapore, Singapore 117542, Singapore; Centre for Bioimaging Sciences, National University of Singapore, Singapore 117546, Singapore
| | - Ruchuan Liu
- Department of Physics, National University of Singapore, Singapore 117542, Singapore; College of Physics, Chongqing University, Chongqing 401331, China
| | - Chwee Teck Lim
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore; Department of Biomedical Engineering, National University of Singapore, Singapore 117575, Singapore; Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore.
| | - Jie Yan
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore; Department of Physics, National University of Singapore, Singapore 117542, Singapore; Centre for Bioimaging Sciences, National University of Singapore, Singapore 117546, Singapore.
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27
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Iwamoto DV, Calderwood DA. Regulation of integrin-mediated adhesions. Curr Opin Cell Biol 2015; 36:41-7. [PMID: 26189062 DOI: 10.1016/j.ceb.2015.06.009] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 06/01/2015] [Accepted: 06/30/2015] [Indexed: 11/18/2022]
Abstract
Integrins are heterodimeric transmembrane adhesion receptors that couple the actin cytoskeleton to the extracellular environment and bidirectionally relay signals across the cell membrane. These processes are critical for cell attachment, migration, differentiation, and survival, and therefore play essential roles in metazoan development, physiology, and pathology. Integrin-mediated adhesions are regulated by diverse factors, including the conformation-specific affinities of integrin receptors for their extracellular ligands, the clustering of integrins and their intracellular binding partners into discrete adhesive structures, mechanical forces exerted on the adhesion, and the intracellular trafficking of integrins themselves. Recent advances shed light onto how the interaction of specific intracellular proteins with the short cytoplasmic tails of integrins controls each of these activities.
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Affiliation(s)
- Daniel V Iwamoto
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA
| | - David A Calderwood
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA; Department of Cell Biology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA.
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28
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Chen H, Yuan G, Winardhi RS, Yao M, Popa I, Fernandez JM, Yan J. Dynamics of equilibrium folding and unfolding transitions of titin immunoglobulin domain under constant forces. J Am Chem Soc 2015; 137:3540-6. [PMID: 25726700 DOI: 10.1021/ja5119368] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The mechanical stability of force-bearing proteins is crucial for their functions. However, slow transition rates of complex protein domains have made it challenging to investigate their equilibrium force-dependent structural transitions. Using ultra stable magnetic tweezers, we report the first equilibrium single-molecule force manipulation study of the classic titin I27 immunoglobulin domain. We found that individual I27 in a tandem repeat unfold/fold independently. We obtained the force-dependent free energy difference between unfolded and folded I27 and determined the critical force (∼5.4 pN) at which unfolding and folding have equal probability. We also determined the force-dependent free energy landscape of unfolding/folding transitions based on measurement of the free energy cost of unfolding. In addition to providing insights into the force-dependent structural transitions of titin I27, our results suggest that the conformations of titin immunoglobulin domains can be significantly altered during low force, long duration muscle stretching.
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Affiliation(s)
- Hu Chen
- †Department of Physics, Xiamen University, Xiamen, Fujian 361005, China.,‡Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Guohua Yuan
- †Department of Physics, Xiamen University, Xiamen, Fujian 361005, China.,‡Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Ricksen S Winardhi
- ‡Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Mingxi Yao
- ‡Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Ionel Popa
- ¶Department of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Julio M Fernandez
- ¶Department of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Jie Yan
- ‡Mechanobiology Institute, National University of Singapore, Singapore 117411.,§Department of Physics, National University of Singapore, Singapore 117542.,∥Centre for Bioimaging Sciences, National University of Singapore, Singapore 117546
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Truong T, Shams H, Mofrad MRK. Mechanisms of integrin and filamin binding and their interplay with talin during early focal adhesion formation. Integr Biol (Camb) 2015; 7:1285-96. [DOI: 10.1039/c5ib00133a] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mechanisms of the interplay among filamin, integrin and talin during early focal adhesion formation were explored using molecular dynamics simulations.
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Affiliation(s)
- Tiffany Truong
- Molecular Cell Biomechanics Laboratory
- Departments of Bioengineering and Mechanical Engineering
- University of California Berkeley
- Berkeley
- USA
| | - Hengameh Shams
- Molecular Cell Biomechanics Laboratory
- Departments of Bioengineering and Mechanical Engineering
- University of California Berkeley
- Berkeley
- USA
| | - Mohammad R. K. Mofrad
- Molecular Cell Biomechanics Laboratory
- Departments of Bioengineering and Mechanical Engineering
- University of California Berkeley
- Berkeley
- USA
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30
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Hua Y, Zhu M, Wang Y, Xie Z, Li M. A hybrid method for identification of structural domains. Sci Rep 2014; 4:7476. [PMID: 25503992 PMCID: PMC4265785 DOI: 10.1038/srep07476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 11/25/2014] [Indexed: 11/10/2022] Open
Abstract
Structural domains in proteins are the basic units to form various proteins. In the protein's evolution and functioning, domains play important roles. But the definition of domain is not yet precisely given, and the update cycle of structural domain databases is long. The automatic algorithms identify domains slowly, while protein entities with great structural complexity are on the rise. Here, we present a method which recognizes the compact and modular segments of polypeptide chains to identify structural domains, and contrast some data sets to illuminate their effect. The method combines support vector machine (SVM) with K-means algorithm. It is faster and more stable than most current algorithms and performs better. It also indicates that when proteins are presented as some Alpha-carbon atoms in 3D space, it is feasible to identify structural domains by the spatially structural properties. We have developed a web-server, which would be helpful in identification of structural domains (http://vis.sculab.org/~huayongpan/cgi-bin/domainAssignment.cgi).
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Affiliation(s)
- Yongpan Hua
- College of Computer Science, Sichuan University, No.24 South Section 1, Yihuan Road, 610064 Chengdu, China
| | - Min Zhu
- College of Computer Science, Sichuan University, No.24 South Section 1, Yihuan Road, 610064 Chengdu, China
| | - Yuelong Wang
- College of Chemistry, Sichuan University, No.24 South Section 1, Yihuan Road, 610065 Chengdu, China
| | - Zhaoyang Xie
- College of Computer Science, Sichuan University, No.24 South Section 1, Yihuan Road, 610064 Chengdu, China
| | - Menglong Li
- College of Chemistry, Sichuan University, No.24 South Section 1, Yihuan Road, 610065 Chengdu, China
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31
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Yan J, Yao M, Goult BT, Sheetz MP. Talin Dependent Mechanosensitivity of Cell Focal Adhesions. Cell Mol Bioeng 2014; 8:151-159. [PMID: 26097520 PMCID: PMC4468797 DOI: 10.1007/s12195-014-0364-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 10/25/2014] [Indexed: 12/11/2022] Open
Abstract
A fundamental question in mechanobiology is how mechanical stimuli are sensed by mechanosensing proteins and converted into signals that direct cells to adapt to the external environment. A key function of cell adhesion to the extracellular matrix (ECM) is to transduce mechanical forces between cells and their extracellular environment. Talin, a cytoplasmic adapter essential for integrin-mediated adhesion to the ECM, links the actin cytoskeleton to integrin at the plasma membrane. Here, we review recent progress in the understanding of talin-dependent mechanosensing revealed by stretching single talin molecules. Rapid progress in single-molecule force manipulation technologies has made it possible to directly study the impact of mechanical force on talin's conformations and its interactions with other signaling proteins. We also provide our views on how findings from such studies may bring new insights into understanding the principles of mechanobiology on a broader scale, and how such fundamental knowledge may be harnessed for mechanopharmacology.
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Affiliation(s)
- Jie Yan
- Mechanobiology Institute, National University of Singapore, Singapore, 117411 Singapore ; Department of Physics, National University of Singapore, Singapore, 117542 Singapore ; Centre for Bioimaging Sciences, National University of Singapore, Singapore, 117546 Singapore
| | - Mingxi Yao
- Mechanobiology Institute, National University of Singapore, Singapore, 117411 Singapore
| | - Benjamin T Goult
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ Kent UK
| | - Michael P Sheetz
- Mechanobiology Institute, National University of Singapore, Singapore, 117411 Singapore ; Department of Biological Sciences, Columbia University, New York, NY 10027 USA
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32
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Documentation and localization of force-mediated filamin A domain perturbations in moving cells. Nat Commun 2014; 5:4656. [PMID: 25120197 PMCID: PMC4139033 DOI: 10.1038/ncomms5656] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 07/10/2014] [Indexed: 12/15/2022] Open
Abstract
Endogenously and externally generated mechanical forces influence diverse cellular activities, a phenomenon defined as mechanotransduction. Deformation of protein domains by application of stress, previously documented to alter macromolecular interactions in vitro, could mediate these effects. We engineered a photon-emitting system responsive to unfolding of two repeat domains of the actin filament (F-actin) crosslinker protein filamin A (FLNA) that binds multiple partners involved in cell signalling reactions and validated the system using F-actin networks subjected to myosin-based contraction. Expressed in cultured cells, the sensor-containing FLNA construct reproducibly reported FLNA domain unfolding strikingly localized to dynamic, actively protruding, leading cell edges. The unfolding signal depends upon coherence of F-actin-FLNA networks and is enhanced by stimulating cell contractility. The results establish protein domain distortion as a bona fide mechanism for mechanotransduction in vivo.
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Yao M, Qiu W, Liu R, Efremov AK, Cong P, Seddiki R, Payre M, Lim CT, Ladoux B, Mège RM, Yan J. Force-dependent conformational switch of α-catenin controls vinculin binding. Nat Commun 2014; 5:4525. [PMID: 25077739 DOI: 10.1038/ncomms5525] [Citation(s) in RCA: 325] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 06/25/2014] [Indexed: 02/08/2023] Open
Abstract
Force sensing at cadherin-mediated adhesions is critical for their proper function. α-Catenin, which links cadherins to actomyosin, has a crucial role in this mechanosensing process. It has been hypothesized that force promotes vinculin binding, although this has never been demonstrated. X-ray structure further suggests that α-catenin adopts a stable auto-inhibitory conformation that makes the vinculin-binding site inaccessible. Here, by stretching single α-catenin molecules using magnetic tweezers, we show that the subdomains MI vinculin-binding domain (VBD) to MIII unfold in three characteristic steps: a reversible step at ~5 pN and two non-equilibrium steps at 10-15 pN. 5 pN unfolding forces trigger vinculin binding to the MI domain in a 1:1 ratio with nanomolar affinity, preventing MI domain refolding after force is released. Our findings demonstrate that physiologically relevant forces reversibly unfurl α-catenin, activating vinculin binding, which then stabilizes α-catenin in its open conformation, transforming force into a sustainable biochemical signal.
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Affiliation(s)
- Mingxi Yao
- 1] Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore [2]
| | - Wu Qiu
- 1] Department of Physics, National University of Singapore, Singapore 117542, Singapore [2] College of Physics, Chongqing University, No. 55 Daxuecheng South Road, Chongqing 401331, China [3]
| | - Ruchuan Liu
- 1] Department of Physics, National University of Singapore, Singapore 117542, Singapore [2] College of Physics, Chongqing University, No. 55 Daxuecheng South Road, Chongqing 401331, China
| | - Artem K Efremov
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
| | - Peiwen Cong
- 1] Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore [2] Singapore-MIT Alliance for Research and Technology, National University of Singapore, Singapore 117543, Singapore
| | - Rima Seddiki
- Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Paris 75013, France
| | - Manon Payre
- Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Paris 75013, France
| | - Chwee Teck Lim
- 1] Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore [2] Department of Bioengineering, National University of Singapore, Singapore 117542, Singapore
| | - Benoit Ladoux
- 1] Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore [2] Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Paris 75013, France
| | - René-Marc Mège
- Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Paris 75013, France
| | - Jie Yan
- 1] Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore [2] College of Physics, Chongqing University, No. 55 Daxuecheng South Road, Chongqing 401331, China [3] Department of Bioengineering, National University of Singapore, Singapore 117542, Singapore [4] Centre for Bioimaging Sciences, National University of Singapore, Singapore 117546, Singapore
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Mechanical activation of vinculin binding to talin locks talin in an unfolded conformation. Sci Rep 2014; 4:4610. [PMID: 24714394 PMCID: PMC3980218 DOI: 10.1038/srep04610] [Citation(s) in RCA: 248] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 03/21/2014] [Indexed: 11/08/2022] Open
Abstract
The force-dependent interaction between talin and vinculin plays a crucial role in the initiation and growth of focal adhesions. Here we use magnetic tweezers to characterise the mechano-sensitive compact N-terminal region of the talin rod, and show that the three helical bundles R1–R3 in this region unfold in three distinct steps consistent with the domains unfolding independently. Mechanical stretching of talin R1–R3 enhances its binding to vinculin and vinculin binding inhibits talin refolding after force is released. Mutations that stabilize R3 identify it as the initial mechano-sensing domain in talin, unfolding at ∼5 pN, suggesting that 5 pN is the force threshold for vinculin binding and adhesion progression.
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35
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Force-dependent isomerization kinetics of a highly conserved proline switch modulates the mechanosensing region of filamin. Proc Natl Acad Sci U S A 2014; 111:5568-73. [PMID: 24706888 DOI: 10.1073/pnas.1319448111] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Proline switches, controlled by cis-trans isomerization, have emerged as a particularly effective regulatory mechanism in a wide range of biological processes. In this study, we use single-molecule mechanical measurements to develop a full kinetic and energetic description of a highly conserved proline switch in the force-sensing domain 20 of human filamin and how prolyl isomerization modulates the force-sensing mechanism. Proline isomerization toggles domain 20 between two conformations. A stable cis conformation with slow unfolding, favoring the autoinhibited closed conformation of filamin's force-sensing domain pair 20-21, and a less stable, uninhibited conformation promoted by the trans form. The data provide detailed insight into the folding mechanisms that underpin the functionality of this binary switch and elucidate its remarkable efficiency in modulating force-sensing, thus combining two previously unconnected regulatory mechanisms, proline switches and mechanosensing.
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36
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Sethi R, Seppälä J, Tossavainen H, Ylilauri M, Ruskamo S, Pentikäinen OT, Pentikäinen U, Permi P, Ylänne J. A novel structural unit in the N-terminal region of filamins. J Biol Chem 2014; 289:8588-98. [PMID: 24469451 DOI: 10.1074/jbc.m113.537456] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Immunoglobulin-like (Ig) domains are a widely expanded superfamily that act as interaction motifs or as structural spacers in multidomain proteins. Vertebrate filamins (FLNs), which are multifunctional actin-binding proteins, consist of 24 Ig domains. We have recently discovered that in the C-terminal rod 2 region of FLN, Ig domains interact with each other forming functional domain pairs, where the interaction with signaling and transmembrane proteins is mechanically regulated by weak actomyosin contraction forces. Here, we investigated if there are similar inter-domain interactions around domain 4 in the N-terminal rod 1 region of FLN. Protein crystal structures revealed a new type of domain organization between domains 3, 4, and 5. In this module, domains 4 and 5 interact rather tightly, whereas domain 3 has a partially flexible interface with domain 4. NMR peptide titration experiments showed that within the three-domain module, domain 4 is capable for interaction with a peptide derived from platelet glycoprotein Ib. Crystal structures of FLN domains 4 and 5 in complex with the peptide revealed a typical β sheet augmentation interaction observed for many FLN ligands. Domain 5 was found to stabilize domain 4, and this could provide a mechanism for the regulation of domain 4 interactions.
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Affiliation(s)
- Ritika Sethi
- From the Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, P. O. Box 35, Survontie 9, 40014 Jyväskylä
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Jahed Z, Shams H, Mehrbod M, Mofrad MRK. Mechanotransduction pathways linking the extracellular matrix to the nucleus. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 310:171-220. [PMID: 24725427 DOI: 10.1016/b978-0-12-800180-6.00005-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cells contain several mechanosensing components that transduce mechanical signals into biochemical cascades. During cell-ECM adhesion, a complex network of molecules mechanically couples the extracellular matrix (ECM), cytoskeleton, and nucleoskeleton. The network comprises transmembrane receptor proteins and focal adhesions, which link the ECM and cytoskeleton. Additionally, recently identified protein complexes extend this linkage to the nucleus by linking the cytoskeleton and the nucleoskeleton. Despite numerous studies in this field, due to the complexity of this network, our knowledge of the mechanisms of cell-ECM adhesion at the molecular level remains remarkably incomplete. Herein, we present a review of the structures of key molecules involved in cell-ECM adhesion, along with an evaluation of their predicted roles in mechanical sensing. Additionally, specific binding events prompted by force-induced conformational changes of each molecule are discussed. Finally, we propose a model for the biomechanical events prominent in cell-ECM adhesion.
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Affiliation(s)
- Zeinab Jahed
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA
| | - Hengameh Shams
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA
| | - Mehrdad Mehrbod
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California at Berkeley, Berkeley, California, USA.
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38
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Ciobanasu C, Faivre B, Le Clainche C. Integrating actin dynamics, mechanotransduction and integrin activation: the multiple functions of actin binding proteins in focal adhesions. Eur J Cell Biol 2013; 92:339-48. [PMID: 24252517 DOI: 10.1016/j.ejcb.2013.10.009] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/10/2013] [Accepted: 10/23/2013] [Indexed: 12/16/2022] Open
Abstract
Focal adhesions are clusters of integrin transmembrane receptors that mechanically couple the extracellular matrix to the actin cytoskeleton during cell migration. Focal adhesions sense and respond to variations in force transmission along a chain of protein-protein interactions linking successively actin filaments, actin binding proteins, integrins and the extracellular matrix to adapt cell-matrix adhesion to the composition and mechanical properties of the extracellular matrix. This review focuses on the molecular mechanisms by which actin binding proteins integrate actin dynamics, mechanotransduction and integrin activation to control force transmission in focal adhesions.
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Affiliation(s)
- Corina Ciobanasu
- Laboratoire d'Enzymologie et Biochimie Structurales CNRS, avenue de la terrasse, 91198 Gif-sur-Yvette, France
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