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Berg A, Velayuthan LP, Tågerud S, Ušaj M, Månsson A. Probing actin-activated ATP turnover kinetics of human cardiac myosin II by single molecule fluorescence. Cytoskeleton (Hoboken) 2024. [PMID: 38623952 DOI: 10.1002/cm.21858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/06/2024] [Accepted: 03/25/2024] [Indexed: 04/17/2024]
Abstract
Mechanistic insights into myosin II energy transduction in striated muscle in health and disease would benefit from functional studies of a wide range of point-mutants. This approach is, however, hampered by the slow turnaround of myosin II expression that usually relies on adenoviruses for gene transfer. A recently developed virus-free method is more time effective but would yield too small amounts of myosin for standard biochemical analyses. However, if the fluorescent adenosine triphosphate (ATP) and single molecule (sm) total internal reflection fluorescence microscopy previously used to analyze basal ATP turnover by myosin alone, can be expanded to actin-activated ATP turnover, it would appreciably reduce the required amount of myosin. To that end, we here describe zero-length cross-linking of human cardiac myosin II motor fragments (sub-fragment 1 long [S1L]) to surface-immobilized actin filaments in a configuration with maintained actin-activated ATP turnover. After optimizing the analysis of sm fluorescence events, we show that the amount of myosin produced from C2C12 cells in one 60 mm cell culture plate is sufficient to obtain both the basal myosin ATP turnover rate and the maximum actin-activated rate constant (kcat). Our analysis of many single binding events of fluorescent ATP to many S1L motor fragments revealed processes reflecting basal and actin-activated ATPase, but also a third exponential process consistent with non-specific ATP-binding outside the active site.
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Affiliation(s)
- Albin Berg
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Science, Linnaeus University, Kalmar, Sweden
| | - Lok Priya Velayuthan
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Science, Linnaeus University, Kalmar, Sweden
| | - Sven Tågerud
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Science, Linnaeus University, Kalmar, Sweden
| | - Marko Ušaj
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Science, Linnaeus University, Kalmar, Sweden
| | - Alf Månsson
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Science, Linnaeus University, Kalmar, Sweden
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2
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Goode BL, Eskin J, Shekhar S. Mechanisms of actin disassembly and turnover. J Cell Biol 2023; 222:e202309021. [PMID: 37948068 PMCID: PMC10638096 DOI: 10.1083/jcb.202309021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/21/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023] Open
Abstract
Cellular actin networks exhibit a wide range of sizes, shapes, and architectures tailored to their biological roles. Once assembled, these filamentous networks are either maintained in a state of polarized turnover or induced to undergo net disassembly. Further, the rates at which the networks are turned over and/or dismantled can vary greatly, from seconds to minutes to hours or even days. Here, we review the molecular machinery and mechanisms employed in cells to drive the disassembly and turnover of actin networks. In particular, we highlight recent discoveries showing that specific combinations of conserved actin disassembly-promoting proteins (cofilin, GMF, twinfilin, Srv2/CAP, coronin, AIP1, capping protein, and profilin) work in concert to debranch, sever, cap, and depolymerize actin filaments, and to recharge actin monomers for new rounds of assembly.
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Affiliation(s)
- Bruce L. Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, USA
| | - Julian Eskin
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, USA
| | - Shashank Shekhar
- Departments of Physics, Cell Biology and Biochemistry, Emory University, Atlanta, GA, USA
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3
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Steffensen KE, Dawson JF. Actin's C-terminus coordinates actin structural changes and functions. Cytoskeleton (Hoboken) 2023; 80:313-329. [PMID: 37036084 DOI: 10.1002/cm.21757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 03/17/2023] [Accepted: 03/30/2023] [Indexed: 04/11/2023]
Abstract
Actin is essential to eukaryotic cellular processes. Actin's C-terminus appears to play a direct role in modulating actin's structure and properties, facilitating the binding and function of actin-binding proteins (ABPs). The structural and functional characterization of filamentous actin's C-terminus has been impeded by its inherent flexibility, as well as actin's resistance to crystallization for x-ray diffraction and the historical resolution constraints associated with electron microscopy. Many biochemical studies have established that actin's C-terminus must retain its flexibility and structural integrity to modulate actin's structure and functions. For example, C-terminal structural changes are known to affect nucleotide binding and exchange, as well as propagate actin structural changes throughout extensive allosteric networks, facilitating the binding and function of ABPs. Advances in electron microscopy have resulted in high-resolution structures of filamentous actin, providing insights into subtle structural changes that are mediated by actin's C-terminus. Here, we review existing knowledge establishing the importance of actin's C-terminus within actin structural changes and functions and discuss how modern structural characterization techniques provide the tools to understand the role of actin's C-terminus in cellular processes.
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Affiliation(s)
- Karl E Steffensen
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - John F Dawson
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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4
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Telek E, Karádi K, Kardos J, Kengyel A, Fekete Z, Halász H, Nyitrai M, Bugyi B, Lukács A. The C-terminal tail extension of myosin 16 acts as a molten globule, including intrinsically disordered regions, and interacts with the N-terminal ankyrin. J Biol Chem 2021; 297:100716. [PMID: 33930467 PMCID: PMC8253979 DOI: 10.1016/j.jbc.2021.100716] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 04/19/2021] [Accepted: 04/26/2021] [Indexed: 11/20/2022] Open
Abstract
The lesser-known unconventional myosin 16 protein is essential in proper neuronal functioning and has been implicated in cell cycle regulation. Its longer Myo16b isoform contains a C-terminal tail extension (Myo16Tail), which has been shown to play a role in the neuronal phosphoinositide 3-kinase signaling pathway. Myo16Tail mediates the actin cytoskeleton remodeling, downregulates the actin dynamics at the postsynaptic site of dendritic spines, and is involved in the organization of the presynaptic axon terminals. However, the functional and structural features of this C-terminal tail extension are not well known. Here, we report the purification and biophysical characterization of the Myo16Tail by bioinformatics, fluorescence spectroscopy, and CD. Our results revealed that the Myo16Tail is functionally active and interacts with the N-terminal ankyrin domain of myosin 16, suggesting an intramolecular binding between the C and N termini of Myo16 as an autoregulatory mechanism involving backfolding of the motor domain. In addition, the Myo16Tail possesses high structural flexibility and a solvent-exposed hydrophobic core, indicating the largely unstructured, intrinsically disordered nature of this protein region. Some secondary structure elements were also observed, indicating that the Myo16Tail likely adopts a molten globule-like structure. These structural features imply that the Myo16Tail may function as a flexible display site particularly relevant in post-translational modifications, regulatory functions such as backfolding, and phosphoinositide 3-kinase signaling.
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Affiliation(s)
- Elek Telek
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Pécs, Hungary
| | - Kristóf Karádi
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; Szentágothai Research Center, Pécs, Hungary
| | - József Kardos
- Department of Biochemistry, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - András Kengyel
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Pécs, Hungary; Szentágothai Research Center, Pécs, Hungary
| | - Zsuzsanna Fekete
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary
| | - Henriett Halász
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Pécs, Hungary
| | - Miklós Nyitrai
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Pécs, Hungary; Szentágothai Research Center, Pécs, Hungary
| | - Beáta Bugyi
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; Szentágothai Research Center, Pécs, Hungary.
| | - András Lukács
- Department of Biophysics, Medical School, University of Pécs, Pécs, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Pécs, Hungary; Szentágothai Research Center, Pécs, Hungary.
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5
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Vizcaíno-Castillo A, Osorio-Méndez JF, Rubio-Ortiz M, Manning-Cela RG, Hernández R, Cevallos AM. Trypanosoma cruzi actins: Expression analysis of actin 2. Biochem Biophys Res Commun 2019; 513:347-353. [DOI: 10.1016/j.bbrc.2019.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 04/01/2019] [Indexed: 10/27/2022]
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6
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Non-enzymatic cleavage of Hsp90 by oxidative stress leads to actin aggregate formation: A novel gain-of-function mechanism. Redox Biol 2019; 21:101108. [PMID: 30660959 PMCID: PMC6348241 DOI: 10.1016/j.redox.2019.101108] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 01/04/2019] [Accepted: 01/10/2019] [Indexed: 01/03/2023] Open
Abstract
Aging is accompanied by the accumulation of oxidized proteins. To remove them, cells employ the proteasomal and autophagy-lysosomal systems; however, if the clearance rate is inferior to its formation, protein aggregates form as a hallmark of proteostasis loss. In cells, during stress conditions, actin aggregates accumulate leading to impaired proliferation and reduced proteasomal activity, as observed in cellular senescence. The heat shock protein 90 (Hsp90) is a molecular chaperone that binds and protects the proteasome from oxidative inactivation. We hypothesized that in oxidative stress conditions a malfunction of Hsp90 occurs resulting in the aforementioned protein aggregates. Here, we demonstrate that upon oxidative stress Hsp90 loses its function in a highly specific non-enzymatic iron-catalyzed oxidation event and its breakdown product, a cleaved form of Hsp90 (Hsp90cl), acquires a new function in mediating the accumulation of actin aggregates. Moreover, the prevention of Hsp90 cleavage reduces oxidized actin accumulation, whereas transfection of the cleaved form of Hsp90 leads to an enhanced accumulation of oxidized actin. This indicates a clear role of the Hsp90cl in the aggregation of oxidized proteins.
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7
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Johnston JR, Chase PB, Pinto JR. Troponin through the looking-glass: emerging roles beyond regulation of striated muscle contraction. Oncotarget 2017; 9:1461-1482. [PMID: 29416706 PMCID: PMC5787451 DOI: 10.18632/oncotarget.22879] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 11/20/2017] [Indexed: 01/03/2023] Open
Abstract
Troponin is a heterotrimeric Ca2+-binding protein that has a well-established role in regulating striated muscle contraction. However, mounting evidence points to novel cellular functions of troponin, with profound implications in cancer, cardiomyopathy pathogenesis and skeletal muscle aging. Here, we highlight the non-canonical roles and aberrant expression patterns of troponin beyond the sarcomeric milieu. Utilizing bioinformatics tools and online databases, we also provide pathway, subcellular localization, and protein-protein/DNA interaction analyses that support a role for troponin in multiple subcellular compartments. This emerging knowledge challenges the conventional view of troponin as a sarcomere-specific protein exclusively involved in muscle contraction and may transform the way we think about sarcomeric proteins, particularly in the context of human disease and aging.
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Affiliation(s)
- Jamie R Johnston
- Department of Biomedical Sciences, The Florida State University College of Medicine, Tallahassee, FL, 32306-4300, USA
| | - P Bryant Chase
- Department of Biological Science, The Florida State University, Tallahassee, FL, 32306-4370, USA
| | - Jose Renato Pinto
- Department of Biomedical Sciences, The Florida State University College of Medicine, Tallahassee, FL, 32306-4300, USA
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8
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Kumar S, Mansson A. Covalent and non-covalent chemical engineering of actin for biotechnological applications. Biotechnol Adv 2017; 35:867-888. [PMID: 28830772 DOI: 10.1016/j.biotechadv.2017.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 08/09/2017] [Accepted: 08/16/2017] [Indexed: 12/26/2022]
Abstract
The cytoskeletal filaments are self-assembled protein polymers with 8-25nm diameters and up to several tens of micrometres length. They have a range of pivotal roles in eukaryotic cells, including transportation of intracellular cargoes (primarily microtubules with dynein and kinesin motors) and cell motility (primarily actin and myosin) where muscle contraction is one example. For two decades, the cytoskeletal filaments and their associated motor systems have been explored for nanotechnological applications including miniaturized sensor systems and lab-on-a-chip devices. Several developments have also revolved around possible exploitation of the filaments alone without their motor partners. Efforts to use the cytoskeletal filaments for applications often require chemical or genetic engineering of the filaments such as specific conjugation with fluorophores, antibodies, oligonucleotides or various macromolecular complexes e.g. nanoparticles. Similar conjugation methods are also instrumental for a range of fundamental biophysical studies. Here we review methods for non-covalent and covalent chemical modifications of actin filaments with focus on critical advantages and challenges of different methods as well as critical steps in the conjugation procedures. We also review potential uses of the engineered actin filaments in nanotechnological applications and in some key fundamental studies of actin and myosin function. Finally, we consider possible future lines of investigation that may be addressed by applying chemical conjugation of actin in new ways.
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Affiliation(s)
- Saroj Kumar
- Department of Biotechnology, Delhi Technological University, Delhi 110042, India; Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden.
| | - Alf Mansson
- Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden.
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9
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Srinivasan S, Guha M, Kashina A, Avadhani NG. Mitochondrial dysfunction and mitochondrial dynamics-The cancer connection. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:602-614. [PMID: 28104365 DOI: 10.1016/j.bbabio.2017.01.004] [Citation(s) in RCA: 258] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 01/03/2017] [Accepted: 01/05/2017] [Indexed: 02/07/2023]
Abstract
Mitochondrial dysfunction is a hallmark of many diseases. The retrograde signaling initiated by dysfunctional mitochondria can bring about global changes in gene expression that alters cell morphology and function. Typically, this is attributed to disruption of important mitochondrial functions, such as ATP production, integration of metabolism, calcium homeostasis and regulation of apoptosis. Recent studies showed that in addition to these factors, mitochondrial dynamics might play an important role in stress signaling. Normal mitochondria are highly dynamic organelles whose size, shape and network are controlled by cell physiology. Defective mitochondrial dynamics play important roles in human diseases. Mitochondrial DNA defects and defective mitochondrial function have been reported in many cancers. Recent studies show that increased mitochondrial fission is a pro-tumorigenic phenotype. In this paper, we have explored the current understanding of the role of mitochondrial dynamics in pathologies. We present new data on mitochondrial dynamics and dysfunction to illustrate a causal link between mitochondrial DNA defects, excessive fission, mitochondrial retrograde signaling and cancer progression. This article is part of a Special Issue entitled Mitochondria in Cancer, edited by Giuseppe Gasparre, Rodrigue Rossignol and Pierre Sonveaux.
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Affiliation(s)
- Satish Srinivasan
- The Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, #189E, Philadelphia, PA 19104, United States
| | - Manti Guha
- The Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, #189E, Philadelphia, PA 19104, United States
| | - Anna Kashina
- The Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, #189E, Philadelphia, PA 19104, United States
| | - Narayan G Avadhani
- The Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, #189E, Philadelphia, PA 19104, United States.
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10
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Spectroscopic characterization of the effect of mouse twinfilin-1 on actin filaments at different pH values. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 164:276-282. [PMID: 27718419 DOI: 10.1016/j.jphotobiol.2016.09.044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 09/26/2016] [Accepted: 09/30/2016] [Indexed: 11/22/2022]
Abstract
The effect of mammalian twinfilin-1 on the structure and dynamics of actin filaments were studied with steady state fluorescence spectroscopy, total internal reflection fluorescence microscopy and differential scanning calorimetry techniques. It was proved before that the eukaryotic budding yeast twinfilin-1 can efficiently bind and severe actin filaments in vitro at low pH values. In the present work steady-state anisotropy measurements revealed that twinfilin can bind efficiently to F-actin. Dilution-induced depolymerization assay proved that mammalian twinfilin-1 has an actin filament severing activity. This severing activity was more pronounced at low pH values. Total internal reflection fluorescence microscopy measurements could support the severing activity of mouse twinfilin-1. The average rate of depolymerization was more apparent at low pH values. The differential scanning calorimetry measurements demonstrated that mammalian twinfilin-1 could reduce the stiffness within the actin filaments before the detachment of the actin protomers. The structural and dynamic reorganization of actin can support the twinfilin-1 induced separation of actin protomers. The measured data indicated that mammalian twinfilin-1 was able to accelerate the monomers dissociation and/or sever the filaments effectively at low pH values. It was concluded that twinfilin-1 can affect the F-actin in biological processes or under stress situations when the pH is markedly under the physiological level.
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11
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Marrero HG, Treistman SN, Lemos JR. Ethanol Effect on BK Channels is Modulated by Magnesium. Alcohol Clin Exp Res 2016; 39:1671-9. [PMID: 26331878 DOI: 10.1111/acer.12821] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 06/17/2015] [Indexed: 11/30/2022]
Abstract
BACKGROUND Alcoholics have been reported to have reduced levels of magnesium in both their extracellular and intracellular compartments. Calcium-dependent potassium channels (BK) are known to be one of ethanol (EtOH)'s better known molecular targets. METHODS Using outside-out patches from hippocampal neuronal cultures, we examined the consequences of altered intracellular Mg(2+) on the effects that EtOH has on BK channels. RESULTS We find that the effect of EtOH is bimodally influenced by the Mg(2+) concentration on the cytoplasmic side. More specifically, when internal Mg(2+) concentrations are ≤200 μM, EtOH decreases BK activity, whereas it increases activity when Mg(2+) is at 1 mM. Similar results are obtained when using patches from HEK cells expressing only the α-subunit of BK. When patches are made with the actin destabilizer cytochalasin D present on the cytoplasmic side, the potentiation caused by EtOH becomes independent of the Mg(2+) concentration. Furthermore, in the presence of the actin stabilizer phalloidin, EtOH causes inhibition even at Mg(2+) concentrations of 1 mM. CONCLUSIONS Internal Mg(2+) can modulate the EtOH effects on BK channels only when there is an intact, internal actin interaction with the channel, as is found at synapses. We propose that the EtOH-induced decrease in cytoplasmic Mg(2+) observed in frequent/chronic drinkers would decrease EtOH's actions on synaptic (e.g., actin-bound) BK channels, producing a form of molecular tolerance.
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Affiliation(s)
| | | | - José R Lemos
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts
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12
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Coumans JVF, Palanisamy SKA, McFarlane J, Moens PDJ. Proteomic and Microscopic Strategies towards the Analysis of the Cytoskeletal Networks in Major Neuropsychiatric Disorders. Int J Mol Sci 2016; 17:E581. [PMID: 27104521 PMCID: PMC4849037 DOI: 10.3390/ijms17040581] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 04/06/2016] [Accepted: 04/08/2016] [Indexed: 11/17/2022] Open
Abstract
Mental health disorders have become worldwide health priorities. It is estimated that in the next 20 years they will account for a 16 trillion United State dollars (US$) loss. Up to now, the underlying pathophysiology of psychiatric disorders remains elusive. Altered cytoskeleton proteins expression that may influence the assembly, organization and maintenance of cytoskeletal integrity has been reported in major depressive disorders, schizophrenia and to some extent bipolar disorders. The use of quantitative proteomics, dynamic microscopy and super-resolution microscopy to investigate disease-specific protein signatures holds great promise to improve our understanding of these disorders. In this review, we present the currently available quantitative proteomic approaches use in neurology, gel-based, stable isotope-labelling and label-free methodologies and evaluate their strengths and limitations. We also reported on enrichment/subfractionation methods that target the cytoskeleton associated proteins and discuss the need of alternative methods for further characterization of the neurocytoskeletal proteome. Finally, we present live cell imaging approaches and emerging dynamic microscopy technology that will provide the tools necessary to investigate protein interactions and their dynamics in the whole cells. While these areas of research are still in their infancy, they offer huge potential towards the understanding of the neuronal network stability and its modification across neuropsychiatric disorders.
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Affiliation(s)
- Joëlle V F Coumans
- School of Rural Medicine, University of New England, Armidale, NSW 2351, Australia.
| | - Suresh K A Palanisamy
- Center for Bioactive Discovery in Health and Aging, School of Science and Technology, University of New England, Armidale, NSW 2351, Australia.
| | - Jim McFarlane
- Center for Bioactive Discovery in Health and Aging, School of Science and Technology, University of New England, Armidale, NSW 2351, Australia.
| | - Pierre D J Moens
- Center for Bioactive Discovery in Health and Aging, School of Science and Technology, University of New England, Armidale, NSW 2351, Australia.
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13
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Türmer K, Orbán J, Gróf P, Nyitrai M. FASCIN and alpha-actinin can regulate the conformation of actin filaments. Biochim Biophys Acta Gen Subj 2015; 1850:1855-61. [PMID: 26025636 DOI: 10.1016/j.bbagen.2015.05.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 05/21/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND Actin filament bundling proteins mediate numerous processes in cells such as the formation of cell membrane protrusions or cell adhesions and stress fiber based locomotion. Among them alpha-actinin and fascin are the most abundant ones. This work characterizes differences in molecular motions in actin filaments due to the binding of these two actin bundling proteins. METHODS We investigated how alpha-actinin and fascin binding modify the conformation of actin filaments by using conventional and saturation transfer EPR methods. RESULTS The result characteristic for motions on the microsecond time scale showed that both actin bundling proteins made the bending and torsional twisting of the actin filaments slower. When nanosecond time scale molecular motions were described the two proteins were found to induce opposite changes in the actin filaments. The binding of one molecule of alpha-actinin or fascin modified the conformation of numerous actin protomers. CONCLUSION As fascin and alpha-actinin participates in different cellular processes their binding can serve the proper tuning of the structure of actin by establishing the right conformation for the interactions with other actin binding proteins. Our observations are in correlation with the model where actin filaments fulfill their biological functions under the regulation by actin-binding proteins. GENERAL SIGNIFICANCE Supporting the general model for the cellular regulation of the actin cytoskeleton we showed that two abundant actin bundling proteins, fascin and alpha-actinin, alter the conformation of actin filaments through long range allosteric interactions in two different ways providing the structural framework for the adaptation to specific biological functions.
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Affiliation(s)
- Katalin Türmer
- Department of Biophysics, Medical School, University of Pécs, Szigeti u. 12, Pécs H-7624, Hungary; János Szentágothai Research Center, Pécs H-7624, Hungary
| | - József Orbán
- Department of Biophysics, Medical School, University of Pécs, Szigeti u. 12, Pécs H-7624, Hungary; János Szentágothai Research Center, Pécs H-7624, Hungary; MTA-PTE High Intensity Terahertz Research Group, Hungary
| | - Pál Gróf
- Department of Biophysics and Radiation Biology, Semmelweis University of Medicine, IX. Tűzoltó u. 37-47, Budapest H-1095, Hungary
| | - Miklós Nyitrai
- Department of Biophysics, Medical School, University of Pécs, Szigeti u. 12, Pécs H-7624, Hungary; János Szentágothai Research Center, Pécs H-7624, Hungary; MTA-PTE Nuclear-Mitochondrial Interactions Research Group, Hungary.
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14
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Wang L, Su B, Cheng C, Ma L, Li S, Nie S, Zhao C. Layer by layer assembly of sulfonic poly(ether sulfone) as heparin-mimicking coatings: scalable fabrication of super-hemocompatible and antibacterial membranes. J Mater Chem B 2015; 3:1391-1404. [PMID: 32264490 DOI: 10.1039/c4tb01865f] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this study, super-hemocompatible and antibacterial polymeric membranes with surface coated nanofilms were fabricated by LBL assembly of water-soluble heparin-mimicking polymer and quaternized chitosan.
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Affiliation(s)
- Lingren Wang
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering
- Sichuan University
- Chengdu 610065
- China
| | - Baihai Su
- Department of Nephrology
- West China Hospital
- Sichuan University
- Chengdu 610041
- People's Republic of China
| | - Chong Cheng
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering
- Sichuan University
- Chengdu 610065
- China
| | - Lang Ma
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering
- Sichuan University
- Chengdu 610065
- China
| | - Shuangsi Li
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering
- Sichuan University
- Chengdu 610065
- China
| | - Shengqiang Nie
- College of Chemistry and Materials Engineering
- Guiyang University
- Guiyang 550005
- China
| | - Changsheng Zhao
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering
- Sichuan University
- Chengdu 610065
- China
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15
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Stanley A, Thompson K, Hynes A, Brakebusch C, Quondamatteo F. NADPH oxidase complex-derived reactive oxygen species, the actin cytoskeleton, and Rho GTPases in cell migration. Antioxid Redox Signal 2014; 20:2026-42. [PMID: 24251358 DOI: 10.1089/ars.2013.5713] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
SIGNIFICANCE Rho GTPases are historically known to be central regulators of actin cytoskeleton reorganization. This affects many processes including cell migration. In addition, members of the Rac subfamily are known to be involved in reactive oxygen species (ROS) production through the regulation of NADPH oxidase (Nox) activity. This review focuses on relationships between Nox-regulated ROS, Rho GTPases, and cytoskeletal reorganization, in the context of cell migration. RECENT ADVANCES It has become clear that ROS participate in the regulation of certain Rho GTPase family members, thus mediating cytoskeletal reorganization. CRITICAL ISSUES The role of the actin cytoskeleton in providing a scaffold for components of the Nox complex needs to be examined in the light of these new advances. During cell migration, Rho GTPases, ROS, and cytoskeletal organization appear to function as a complex regulatory network. However, more work is needed to fully elucidate the interactions between these factors and their potential in vivo importance. FUTURE DIRECTIONS Ultrastructural analysis, that is, electron microscopy, particularly immunogold labeling, will enable direct visualization of subcellular compartments. This in conjunction with the analysis of tissues lacking specific Rho GTPases, and Nox components will facilitate a detailed examination of the interactions of these structures with the actin cytoskeleton. In combination with the analysis of ROS production, including its subcellular location, these data will contribute significantly to our understanding of this intricate network under physiological conditions. Based on this, in vivo and in vitro studies can then be combined to elucidate the signaling pathways involved and their targets.
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Affiliation(s)
- Alanna Stanley
- 1 Skin and Extracellular Matrix Research Group , Anatomy, NUI Galway, Galway, Ireland
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16
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ten Siethoff L, Lard M, Generosi J, Andersson H, Linke H, Månsson A. Molecular motor propelled filaments reveal light-guiding in nanowire arrays for enhanced biosensing. NANO LETTERS 2014; 14:737-42. [PMID: 24367994 PMCID: PMC3924849 DOI: 10.1021/nl404032k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 12/17/2013] [Indexed: 05/27/2023]
Abstract
Semiconductor nanowire arrays offer significant potential for biosensing applications with optical read-out due to their high surface area and due to the unique optical properties of one-dimensional materials. A challenge for optical read-out of analyte-binding to the nanowires is the need to efficiently collect and detect light from a three-dimensional volume. Here we show that light from fluorophores attached along several μm long vertical Al2O3 coated gallium phosphide nanowires couples into the wires, is guided along them and emitted at the tip. This enables effective collection of light emitted by fluorescent analytes located at different focal planes along the nanowire. We unequivocally demonstrate the light-guiding effect using a novel method whereby the changes in emitted fluorescence intensity are observed when fluorescent cytoskeletal filaments are propelled by molecular motors along the wires. The findings are discussed in relation to nanobiosensor developments, other nanotechnological applications, and fundamental studies of motor function.
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Affiliation(s)
- Lasse ten Siethoff
- Department
of Chemistry and Biomedical Sciences, Linnaeus
University, SE-391 82 Kalmar, Sweden
| | - Mercy Lard
- Nanometer
Structure Consortium (nmC@LU) and Solid State Physics Lund University, SE-221 00 Lund, Sweden
| | - Johanna Generosi
- Nanometer
Structure Consortium (nmC@LU) and Solid State Physics Lund University, SE-221 00 Lund, Sweden
| | - Håkan
S. Andersson
- Department
of Chemistry and Biomedical Sciences, Linnaeus
University, SE-391 82 Kalmar, Sweden
| | - Heiner Linke
- Nanometer
Structure Consortium (nmC@LU) and Solid State Physics Lund University, SE-221 00 Lund, Sweden
| | - Alf Månsson
- Department
of Chemistry and Biomedical Sciences, Linnaeus
University, SE-391 82 Kalmar, Sweden
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17
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Bengtsson E, Persson M, Månsson A. Analysis of flexural rigidity of actin filaments propelled by surface adsorbed myosin motors. Cytoskeleton (Hoboken) 2013; 70:718-28. [PMID: 24039103 PMCID: PMC4230416 DOI: 10.1002/cm.21138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 08/08/2013] [Accepted: 08/22/2013] [Indexed: 11/09/2022]
Abstract
Actin filaments are central components of the cytoskeleton and the contractile machinery of muscle. The filaments are known to exist in a range of conformational states presumably with different flexural rigidity and thereby different persistence lengths. Our results analyze the approaches proposed previously to measure the persistence length from the statistics of the winding paths of actin filaments that are propelled by surface-adsorbed myosin motor fragments in the in vitro motility assay. Our results suggest that the persistence length of heavy meromyosin propelled actin filaments can be estimated with high accuracy and reproducibility using this approach provided that: (1) the in vitro motility assay experiments are designed to prevent bias in filament sliding directions, (2) at least 200 independent filament paths are studied, (3) the ratio between the sliding distance between measurements and the camera pixel-size is between 4 and 12, (4) the sliding distances between measurements is less than 50% of the expected persistence length, and (5) an appropriate cut-off value is chosen to exclude abrupt large angular changes in sliding direction that are complications, e.g., due to the presence of rigor heads. If the above precautions are taken the described method should be a useful routine part of in vitro motility assays thus expanding the amount of information to be gained from these.
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Affiliation(s)
- Elina Bengtsson
- Faculty of Health and Life Sciences, Linnaeus University, Kalmar, Sweden
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18
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Interaction of formin FH2 with skeletal muscle actin. EPR and DSC studies. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2013; 42:757-65. [PMID: 23949957 PMCID: PMC3824300 DOI: 10.1007/s00249-013-0922-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 07/05/2013] [Accepted: 07/22/2013] [Indexed: 10/31/2022]
Abstract
Formins are highly conserved proteins that are essential in the formation and regulation of the actin cytoskeleton. The formin homology 2 (FH2) domain is responsible for actin binding and acts as an important nucleating factor in eukaryotic cells. In this work EPR and DSC were used to investigate the properties of the mDia1-FH2 formin fragment and its interaction with actin. MDia1-FH2 was labeled with a maleimide spin probe (MSL). EPR results suggested that the MSL was attached to a single SH group in the FH2. In DSC and temperature-dependent EPR experiments we observed that mDia1-FH2 has a flexible structure and observed a major temperature-induced conformational change at 41 °C. The results also confirmed the previous observation obtained by fluorescence methods that formin binding can destabilize the structure of actin filaments. In the EPR experiments the intermolecular connection between the monomers of formin dimers proved to be flexible. Considering the complex molecular mechanisms underlying the cellular roles of formins this internal flexibility of the dimers is probably important for manifestation of their biological functions.
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19
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Lee BC, Péterfi Z, Hoffmann FW, Moore RE, Kaya A, Avanesov A, Tarrago L, Zhou Y, Weerapana E, Fomenko DE, Hoffmann PR, Gladyshev VN. MsrB1 and MICALs regulate actin assembly and macrophage function via reversible stereoselective methionine oxidation. Mol Cell 2013; 51:397-404. [PMID: 23911929 DOI: 10.1016/j.molcel.2013.06.019] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/11/2013] [Accepted: 06/25/2013] [Indexed: 01/17/2023]
Abstract
Redox control of protein function involves oxidation and reduction of amino acid residues, but the mechanisms and regulators involved are insufficiently understood. Here, we report that in conjunction with Mical proteins, methionine-R-sulfoxide reductase B1 (MsrB1) regulates mammalian actin assembly via stereoselective methionine oxidation and reduction in a reversible, site-specific manner. Two methionine residues in actin are specifically converted to methionine-R-sulfoxide by Mical1 and Mical2 and reduced back to methionine by selenoprotein MsrB1, supporting actin disassembly and assembly, respectively. Macrophages utilize this redox control during cellular activation by stimulating MsrB1 expression and activity as a part of innate immunity. We identified the regulatory role of MsrB1 as a Mical antagonist in orchestrating actin dynamics and macrophage function. More generally, our study shows that proteins can be regulated by reversible site-specific methionine-R-sulfoxidation.
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Affiliation(s)
- Byung Cheon Lee
- Division of Genetics, Department of Medicine, Brigham & Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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20
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Blache U, Silván U, Plodinec M, Suetterlin R, Jakob R, Klebba I, Bentires-Alj M, Aebi U, Schoenenberger CA. A tumorigenic actin mutant alters fibroblast morphology and multicellular assembly properties. Cytoskeleton (Hoboken) 2013; 70:635-50. [DOI: 10.1002/cm.21120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 06/07/2013] [Accepted: 06/17/2013] [Indexed: 01/19/2023]
Affiliation(s)
- Ulrich Blache
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
| | - Unai Silván
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
| | - Marija Plodinec
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
| | - Rosmarie Suetterlin
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
| | - Roman Jakob
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
| | - Ina Klebba
- Mechanisms of Cancer; Friedrich Miescher Institute for Biomedical Research; Basel Switzerland
| | - Mohamed Bentires-Alj
- Mechanisms of Cancer; Friedrich Miescher Institute for Biomedical Research; Basel Switzerland
| | - Ueli Aebi
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
| | - Cora-Ann Schoenenberger
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
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21
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Sharma S, Zhu H, Grintsevich EE, Reisler E, Gimzewski JK. Correlative nanoscale imaging of actin filaments and their complexes. NANOSCALE 2013; 5:5692-702. [PMID: 23727693 PMCID: PMC4030708 DOI: 10.1039/c3nr01039b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Actin remodeling is an area of interest in biology in which correlative microscopy can bring a new way to analyze protein complexes at the nanoscale. Advances in EM, X-ray diffraction, fluorescence, and single molecule techniques have provided a wealth of information about the modulation of the F-actin structure and its regulation by actin binding proteins (ABPs). Yet, there are technological limitations of these approaches to achieving quantitative molecular level information on the structural and biophysical changes resulting from ABPs interaction with F-actin. Fundamental questions about the actin structure and dynamics and how these determine the function of ABPs remain unanswered. Specifically, how local and long-range structural and conformational changes result in ABPs induced remodeling of F-actin needs to be addressed at the single filament level. Advanced, sensitive and accurate experimental tools for detailed understanding of ABP-actin interactions are much needed. This article discusses the current understanding of nanoscale structural and mechanical modulation of F-actin by ABPs at the single filament level using several correlative microscopic techniques, focusing mainly on results obtained by Atomic Force Microscopy (AFM) analysis of ABP-actin complexes.
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Affiliation(s)
- Shivani Sharma
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, USA. Fax: +1 310 206 4038; +1 310 206 4038; Tel: +1 310 794 7514; +1 310 983 1027
- California NanoSystems Institute, University of California, Los Angeles, California, USA
| | - Huanqi Zhu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, USA. Fax: +1 310 206 4038; +1 310 206 4038; Tel: +1 310 794 7514; +1 310 983 1027
| | - Elena E. Grintsevich
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, USA. Fax: +1 310 206 4038; +1 310 206 4038; Tel: +1 310 794 7514; +1 310 983 1027
| | - Emil Reisler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, USA. Fax: +1 310 206 4038; +1 310 206 4038; Tel: +1 310 794 7514; +1 310 983 1027
- Molecular Biology Institute, University of California, Los Angeles, California, USA
| | - James K. Gimzewski
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, USA. Fax: +1 310 206 4038; +1 310 206 4038; Tel: +1 310 794 7514; +1 310 983 1027
- California NanoSystems Institute, University of California, Los Angeles, California, USA
- International Center for Materials Nanoarchitectonics Satellite (MANA), National Institute for Materials Science (NIMS), Tsukuba, Japan
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22
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Favini-Stabile S, Contreras-Martel C, Thielens N, Dessen A. MreB and MurG as scaffolds for the cytoplasmic steps of peptidoglycan biosynthesis. Environ Microbiol 2013; 15:3218-28. [DOI: 10.1111/1462-2920.12171] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Accepted: 05/27/2013] [Indexed: 11/27/2022]
Affiliation(s)
- Sandy Favini-Stabile
- Institut de Biologie Structurale (IBS); Université Grenoble I; Grenoble France
- Commissariat à l'Energie Atomique (CEA); Grenoble France
- Centre National de la Recherche Scientifique (CNRS); Grenoble France
| | - Carlos Contreras-Martel
- Institut de Biologie Structurale (IBS); Université Grenoble I; Grenoble France
- Commissariat à l'Energie Atomique (CEA); Grenoble France
- Centre National de la Recherche Scientifique (CNRS); Grenoble France
| | - Nicole Thielens
- Institut de Biologie Structurale (IBS); Université Grenoble I; Grenoble France
- Commissariat à l'Energie Atomique (CEA); Grenoble France
- Centre National de la Recherche Scientifique (CNRS); Grenoble France
| | - Andréa Dessen
- Institut de Biologie Structurale (IBS); Université Grenoble I; Grenoble France
- Commissariat à l'Energie Atomique (CEA); Grenoble France
- Centre National de la Recherche Scientifique (CNRS); Grenoble France
- Brazilian National Laboratory for Biosciences (LNBio); CNPEM; Campinas São Paulo Brazil
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23
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Nag S, Larsson M, Robinson RC, Burtnick LD. Gelsolin: The tail of a molecular gymnast. Cytoskeleton (Hoboken) 2013; 70:360-84. [DOI: 10.1002/cm.21117] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 05/24/2013] [Indexed: 12/14/2022]
Affiliation(s)
| | - Mårten Larsson
- Institute of Molecular and Cell Biology, A*STAR; Singapore
| | | | - Leslie D. Burtnick
- Department of Chemistry and Centre for Blood Research; Life Sciences Institute, University of British Columbia; Vancouver; British Columbia; Canada
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24
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Castro JP, Jung T, Grune T, Almeida H. Actin carbonylation: from cell dysfunction to organism disorder. J Proteomics 2013; 92:171-80. [PMID: 23684956 DOI: 10.1016/j.jprot.2013.05.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 05/03/2013] [Accepted: 05/06/2013] [Indexed: 12/22/2022]
Abstract
Protein carbonylation is an important event in the context of proteostasis because of its frequency, non-enzymatic nature and irreversible effects. The carbonylation of proteins disturbs their function and leads to protein aggregates, which may precede cellular senescence and cell death. Actin, an evolutionarily conserved cytoskeletal protein that is involved in important cellular processes, is one of the proteins most susceptible to carbonylation. Conditions resulting in oxidative stress are likely to lead to its carbonylation, loss of function and aggregate formation. In this review, we summarise actin susceptibility to carbonylation, as verified in cell free extracts, cell lines and animal models, and review its fate through the activation of cell mechanisms aimed at removing damaged proteins. Their insufficient activity may underlie age-related diseases and the ageing process. This article is part of a Special Issue entitled: Posttranslational Protein modifications in biology and Medicine.
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Affiliation(s)
- José Pedro Castro
- Departamento de Biologia Experimental, Faculdade de Medicina da Universidade do Porto, 4200-319 Porto, Portugal; IBMC-Instituto de Biologia Molecular e Celular, 4150-180 Porto, Portugal; Institute of Nutrition, Friedrich Schiller Universität Jena, Dornburger Str. 24, 07743 Jena, Germany
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25
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Wang L, Wang M, Wang S, Qi T, Guo L, Li J, Qi W, Ampah KK, Ba X, Zeng X. Actin polymerization negatively regulates p53 function by impairing its nuclear import in response to DNA damage. PLoS One 2013; 8:e60179. [PMID: 23565200 PMCID: PMC3615075 DOI: 10.1371/journal.pone.0060179] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 02/25/2013] [Indexed: 11/29/2022] Open
Abstract
Actin, one of the most evolutionarily conservative proteins in eukaryotes, is distributed both in the cytoplasm and the nucleus, and its dynamics plays important roles in numerous cellular processes. Previous evidence has shown that actin interacts with p53 and this interaction increases in the process of p53 responding to DNA damage, but the physiological significance of their interaction remains elusive. Here, we show that DNA damage induces both actin polymerization and p53 accumulation. To further understand the implication of actin polymerization in p53 function, cells were treated with actin aggregation agent. We find that the protein level of p53 decrease. The change in p53 is a consequence of the polymeric actin anchoring p53 in the cytoplasm, thus impairing p53 nuclear import. Analysis of phosphorylation and ubiquitination of p53 reveals that actin polymerization promotes the p53 phosphorylation at Ser315 and reduces the stabilization of p53 by recruiting Aurora kinase A. Taken together, our results suggest that the actin polymerization serves as a negative modulator leading to the impairment of nuclear import and destabilization of p53. On the basis of our results, we propose that actin polymerization might be a factor participating in the process of orchestrating p53 function in response to DNA damage.
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Affiliation(s)
- Ling Wang
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Min Wang
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Shuyan Wang
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Tianyang Qi
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Lijing Guo
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Jinjiao Li
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Wenjing Qi
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Khamal Kwesi Ampah
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
| | - Xueqing Ba
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
- * E-mail: (XB); (XZ)
| | - Xianlu Zeng
- Key Laboratory of Molecular Epigenetics of MOE and the Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin, China
- * E-mail: (XB); (XZ)
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26
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Persson M, Gullberg M, Tolf C, Lindberg AM, Månsson A, Kocer A. Transportation of nanoscale cargoes by myosin propelled actin filaments. PLoS One 2013; 8:e55931. [PMID: 23437074 PMCID: PMC3578877 DOI: 10.1371/journal.pone.0055931] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 01/03/2013] [Indexed: 02/04/2023] Open
Abstract
Myosin II propelled actin filaments move ten times faster than kinesin driven microtubules and are thus attractive candidates as cargo-transporting shuttles in motor driven lab-on-a-chip devices. In addition, actomyosin-based transportation of nanoparticles is useful in various fundamental studies. However, it is poorly understood how actomyosin function is affected by different number of nanoscale cargoes, by cargo size, and by the mode of cargo-attachment to the actin filament. This is studied here using biotin/fluorophores, streptavidin, streptavidin-coated quantum dots, and liposomes as model cargoes attached to monomers along the actin filaments (“side-attached”) or to the trailing filament end via the plus end capping protein CapZ. Long-distance transportation (>100 µm) could be seen for all cargoes independently of attachment mode but the fraction of motile filaments decreased with increasing number of side-attached cargoes, a reduction that occurred within a range of 10–50 streptavidin molecules, 1–10 quantum dots or with just 1 liposome. However, as observed by monitoring these motile filaments with the attached cargo, the velocity was little affected. This also applied for end-attached cargoes where the attachment was mediated by CapZ. The results with side-attached cargoes argue against certain models for chemomechanical energy transduction in actomyosin and give important insights of relevance for effective exploitation of actomyosin-based cargo-transportation in molecular diagnostics and other nanotechnological applications. The attachment of quantum dots via CapZ, without appreciable modulation of actomyosin function, is useful in fundamental studies as exemplified here by tracking with nanometer accuracy.
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Affiliation(s)
- Malin Persson
- School of Natural Sciences, Linnaeus University, Kalmar, Sweden
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27
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Fan J, Saunders MG, Voth GA. Coarse-graining provides insights on the essential nature of heterogeneity in actin filaments. Biophys J 2013; 103:1334-42. [PMID: 22995506 DOI: 10.1016/j.bpj.2012.08.029] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 06/21/2012] [Accepted: 08/08/2012] [Indexed: 10/27/2022] Open
Abstract
Experiments have shown that actin is structurally polymorphic, but knowledge of the details of molecular level heterogeneity in both the dynamics of a single subunit and the interactions between subunits is still lacking. Here, using atomistic molecular dynamics simulations of the actin filament, we identify domains of atoms that move in a correlated fashion, quantify interactions between these domains using coarse-grained (CG) analysis methods, and perform CG simulations to explore the importance of filament heterogeneity. The persistence length and torsional stiffness calculated from molecular dynamics simulation data agree with experimental values. We additionally observe that distinct actin conformations coexist in actin filaments. The filaments also exhibit random twist angles that are broadly distributed. CG analysis reveals that interactions between equivalent CG pairs vary from one subunit to another. To explore the importance of heterogeneity on filament dynamics, we perform CG simulations using different methods of parameterization to show that only by including heterogeneous interactions can we reproduce the twist angles and related properties. Free energy calculations further suggest that in general the actin filament is best represented as a set of subunits with differing CG sites and interactions, and the incorporating heterogeneity into the CG interactions is more important than including that in the CG sites. Our work therefore presents a systematic method to explore molecular level detail in this large and complex biopolymer.
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Affiliation(s)
- Jun Fan
- Department of Chemistry, Institute for Biophysical Dynamics, James Franck Institute, University of Chicago, Chicago, Illinois, USA
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28
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Fan J, Saunders MG, Haddadian EJ, Freed KF, De La Cruz EM, Voth GA. Molecular origins of cofilin-linked changes in actin filament mechanics. J Mol Biol 2013; 425:1225-40. [PMID: 23352932 DOI: 10.1016/j.jmb.2013.01.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 01/14/2013] [Accepted: 01/16/2013] [Indexed: 10/27/2022]
Abstract
The actin regulatory protein cofilin plays a central role in actin assembly dynamics by severing filaments and increasing the concentration of ends from which subunits add and dissociate. Cofilin binding modifies the average structure and mechanical properties of actin filaments, thereby promoting fragmentation of partially decorated filaments at boundaries of bare and cofilin-decorated segments. Despite extensive evidence for cofilin-dependent changes in filament structure and mechanics, it is unclear how the two processes are linked at the molecular level. Here, we use molecular dynamics simulations and coarse-grained analyses to evaluate the molecular origins of the changes in filament compliance due to cofilin binding. Filament subunits with bound cofilin are less flat and maintain a significantly more open nucleotide cleft than bare filament subunits. Decorated filament segments are less twisted, thinner (considering only actin), and less connected than their bare counterparts, which lowers the filament bending persistence length and torsional stiffness. Using coarse-graining as an analysis method reveals that cofilin binding increases the average distance between the adjacent long-axis filament subunit, thereby weakening their interaction. In contrast, a fraction of lateral filament subunit contacts are closer and presumably stronger with cofilin binding. A cofilactin interface contact identified by cryo-electron microscopy is unstable during simulations carried out at 310K, suggesting that this particular interaction may be short lived at ambient temperatures. These results reveal the molecular origins of cofilin-dependent changes in actin filament mechanics that may promote filament severing.
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Affiliation(s)
- Jun Fan
- Department of Chemistry, James Franck Institute, Computation Institute, University of Chicago, 5735 South Ellis Avenue, Chicago, IL 60637, USA
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29
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Wong GTH, Chang RCC, Law ACK. A breach in the scaffold: the possible role of cytoskeleton dysfunction in the pathogenesis of major depression. Ageing Res Rev 2013; 12:67-75. [PMID: 22995339 DOI: 10.1016/j.arr.2012.08.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 08/31/2012] [Accepted: 08/31/2012] [Indexed: 11/29/2022]
Abstract
Depression is one of the most common psychiatric disorders with inadequately understood disease mechanisms. It has long been considered that dendritic regression and decrease in the number of dendritic spines are involved in depression. Dendrites made up of microtubules and actin filaments form synapses with neighboring neurons, which come together as an important communication network. Cytoskeletal proteins undergo post-translational modifications to define their structure and function. In depression and other psychiatric disorders, post-translational modifications may be disrupted that can result in altered cytoskeletal functions. The disruption of microtubule and actin in terms of morphology and functions may be a leading cause of dendritic regression and decrease in dendritic spine in depression.
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Affiliation(s)
- Ginger Tsz-Hin Wong
- Neurodysfunction Research Laboratory, Department of Psychiatry, LKS Faculty of Medicine, Hong Kong Special Administrative Region, China
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Kumar S, ten Siethoff L, Persson M, Lard M, te Kronnie G, Linke H, Månsson A. Antibodies covalently immobilized on actin filaments for fast myosin driven analyte transport. PLoS One 2012; 7:e46298. [PMID: 23056279 PMCID: PMC3463588 DOI: 10.1371/journal.pone.0046298] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 08/29/2012] [Indexed: 01/09/2023] Open
Abstract
Biosensors would benefit from further miniaturization, increased detection rate and independence from external pumps and other bulky equipment. Whereas transportation systems built around molecular motors and cytoskeletal filaments hold significant promise in the latter regard, recent proof-of-principle devices based on the microtubule-kinesin motor system have not matched the speed of existing methods. An attractive solution to overcome this limitation would be the use of myosin driven propulsion of actin filaments which offers motility one order of magnitude faster than the kinesin-microtubule system. Here, we realized a necessary requirement for the use of the actomyosin system in biosensing devices, namely covalent attachment of antibodies to actin filaments using heterobifunctional cross-linkers. We also demonstrated consistent and rapid myosin II driven transport where velocity and the fraction of motile actin filaments was negligibly affected by the presence of antibody-antigen complexes at rather high density (>20 µm(-1)). The results, however, also demonstrated that it was challenging to consistently achieve high density of functional antibodies along the actin filament, and optimization of the covalent coupling procedure to increase labeling density should be a major focus for future work. Despite the remaining challenges, the reported advances are important steps towards considerably faster nanoseparation than shown for previous molecular motor based devices, and enhanced miniaturization because of high bending flexibility of actin filaments.
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Affiliation(s)
- Saroj Kumar
- School of Natural Sciences, Linnaeus University, Kalmar, Sweden
| | | | - Malin Persson
- School of Natural Sciences, Linnaeus University, Kalmar, Sweden
| | - Mercy Lard
- The Nanometer Structure Consortium and Division of Solid State Physics, Lund University, Lund, Sweden
| | - Geertruy te Kronnie
- Department of Women’s and Children’s Health, University of Padua, Padova, Italy
| | - Heiner Linke
- The Nanometer Structure Consortium and Division of Solid State Physics, Lund University, Lund, Sweden
| | - Alf Månsson
- School of Natural Sciences, Linnaeus University, Kalmar, Sweden
- * E-mail:
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Ujfalusi Z, Kovács M, Nagy NT, Barkó S, Hild G, Lukács A, Nyitrai M, Bugyi B. Myosin and tropomyosin stabilize the conformation of formin-nucleated actin filaments. J Biol Chem 2012; 287:31894-904. [PMID: 22753415 PMCID: PMC3442522 DOI: 10.1074/jbc.m112.341230] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The conformational elasticity of the actin cytoskeleton is essential for its versatile biological functions. Increasing evidence supports that the interplay between the structural and functional properties of actin filaments is finely regulated by actin-binding proteins; however, the underlying mechanisms and biological consequences are not completely understood. Previous studies showed that the binding of formins to the barbed end induces conformational transitions in actin filaments by making them more flexible through long range allosteric interactions. These conformational changes are accompanied by altered functional properties of the filaments. To get insight into the conformational regulation of formin-nucleated actin structures, in the present work we investigated in detail how binding partners of formin-generated actin structures, myosin and tropomyosin, affect the conformation of the formin-nucleated actin filaments using fluorescence spectroscopic approaches. Time-dependent fluorescence anisotropy and temperature-dependent Förster-type resonance energy transfer measurements revealed that heavy meromyosin, similarly to tropomyosin, restores the formin-induced effects and stabilizes the conformation of actin filaments. The stabilizing effect of heavy meromyosin is cooperative. The kinetic analysis revealed that despite the qualitatively similar effects of heavy meromyosin and tropomyosin on the conformational dynamics of actin filaments the mechanisms of the conformational transition are different for the two proteins. Heavy meromyosin stabilizes the formin-nucleated actin filaments in an apparently single step reaction upon binding, whereas the stabilization by tropomyosin occurs after complex formation. These observations support the idea that actin-binding proteins are key elements of the molecular mechanisms that regulate the conformational and functional diversity of actin filaments in living cells.
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Affiliation(s)
- Zoltán Ujfalusi
- Department of Biophysics, Medical School, University of Pécs, Szigeti Street 12, H-7624 Pécs, Hungary
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Wiggan O, Shaw AE, DeLuca JG, Bamburg JR. ADF/cofilin regulates actomyosin assembly through competitive inhibition of myosin II binding to F-actin. Dev Cell 2012; 22:530-43. [PMID: 22421043 DOI: 10.1016/j.devcel.2011.12.026] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 12/30/2011] [Accepted: 12/31/2011] [Indexed: 11/29/2022]
Abstract
The contractile actin cortex is important for diverse fundamental cell processes, but little is known about how the assembly of F-actin and myosin II motors is regulated. We report that depletion of actin depolymerizing factor (ADF)/cofilin proteins in human cells causes increased contractile cortical actomyosin assembly. Remarkably, our data reveal that the major cellular defects resulting from ADF/cofilin depletion, including cortical F-actin accumulation, were largely due to excessive myosin II activity. We identify that ADF/cofilins from unicellular organisms to humans share a conserved activity to inhibit myosin II binding to F-actin, indicating a mechanistic rationale for our cellular results. Our study establishes an essential requirement for ADF/cofilin proteins in the control of normal cortical contractility and in processes such as mitotic karyokinesis. We propose that ADF/cofilin proteins are necessary for controlling actomyosin assembly and intracellular contractile force generation, a function of equal physiological importance to their established roles in mediating F-actin turnover.
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Affiliation(s)
- O'Neil Wiggan
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA.
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Abstract
Eukaryotic cells generate a diversity of actin filament networks in a common cytoplasm to optimally perform functions such as cell motility, cell adhesion, endocytosis and cytokinesis. Each of these networks maintains precise mechanical and dynamic properties by autonomously controlling the composition of its interacting proteins and spatial organization of its actin filaments. In this review, we discuss the chemical and physical mechanisms that target distinct sets of actin-binding proteins to distinct actin filament populations after nucleation, resulting in the assembly of actin filament networks that are optimized for specific functions.
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Affiliation(s)
- Alphée Michelot
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3202, USA.
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Uyeda TQP, Iwadate Y, Umeki N, Nagasaki A, Yumura S. Stretching actin filaments within cells enhances their affinity for the myosin II motor domain. PLoS One 2011; 6:e26200. [PMID: 22022566 PMCID: PMC3192770 DOI: 10.1371/journal.pone.0026200] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 09/22/2011] [Indexed: 11/18/2022] Open
Abstract
To test the hypothesis that the myosin II motor domain (S1) preferentially binds to specific subsets of actin filaments in vivo, we expressed GFP-fused S1 with mutations that enhanced its affinity for actin in Dictyostelium cells. Consistent with the hypothesis, the GFP-S1 mutants were localized along specific portions of the cell cortex. Comparison with rhodamine-phalloidin staining in fixed cells demonstrated that the GFP-S1 probes preferentially bound to actin filaments in the rear cortex and cleavage furrows, where actin filaments are stretched by interaction with endogenous myosin II filaments. The GFP-S1 probes were similarly enriched in the cortex stretched passively by traction forces in the absence of myosin II or by external forces using a microcapillary. The preferential binding of GFP-S1 mutants to stretched actin filaments did not depend on cortexillin I or PTEN, two proteins previously implicated in the recruitment of myosin II filaments to stretched cortex. These results suggested that it is the stretching of the actin filaments itself that increases their affinity for the myosin II motor domain. In contrast, the GFP-fused myosin I motor domain did not localize to stretched actin filaments, which suggests different preferences of the motor domains for different structures of actin filaments play a role in distinct intracellular localizations of myosin I and II. We propose a scheme in which the stretching of actin filaments, the preferential binding of myosin II filaments to stretched actin filaments, and myosin II-dependent contraction form a positive feedback loop that contributes to the stabilization of cell polarity and to the responsiveness of the cells to external mechanical stimuli.
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Affiliation(s)
- Taro Q P Uyeda
- National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan.
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