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Pérez-Mozqueda LL, Vazquez-Duhalt R, Castro-Longoria E. Role and dynamics of an agmatinase-like protein (AGM-1) in Neurospora crassa. Fungal Genet Biol 2019; 132:103264. [PMID: 31465847 DOI: 10.1016/j.fgb.2019.103264] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 08/09/2019] [Accepted: 08/22/2019] [Indexed: 10/26/2022]
Abstract
Agmatinase is known as a metalloenzyme which hydrolyzes agmatine to produce urea and putrescine, being crucial in the alternative pathway to produce polyamines. In this study, an agmatinase-like protein (AGM-1) (NCU 01348) in the filamentous fungus Neurospora crassa is reported. Purified AGM-1 from N. crassa displays enzymatic activity hydrolyzing agmatine; therefore, it can be considered as an agmatinase-like protein. However, its role in the alternative pathway to produce polyamines apparently is not its main function since only a slight reduction of polyamines concentration was detected in the Δagm-1 het strain. Moreover, the null mutant Δagm-1 (homokaryon strain) was unable to grow and the deficiency of agm-1 in the heterokaryon strain provoked a decrease in elongation rate, conidia and biomass production, despite of having de constitutive pathway via the ornithine decarboxylase (ODC). Additionally, mature hyphae of the Δagm-1 het strain presented unusual apical branching and a disorganized Spitzenkörper (Spk). Trying to reveal the role of AGM-1in N. crassa, the protein was tagged with GFP and interestingly the dynamics and intracellular localization of AGM-1 closely resembles the F-actin population. This finding was further examined in order to elucidate if AGM-1is in a close association with F-actin. Since polyamines, among them agmatine, have been reported to act as stabilizers of actin filaments, we evaluated in vitro G-actin polymerization in the presence of agmatine and the effect of purified AGM-1 from N. crassa on these polymerized actin filaments. It was found that polymerization of actin filaments increases in the presence of agmatine and the addition of purified AGM-1 from N. crassa depolymerizes these actin filaments. Also, it was determined that an intact substrate binding site of the enzyme is necessary for the localization pattern of the native AGM-1. These results suggest that in N. crassa AGM-1 has a close association with the F-actin population via its substrate agmatine, playing an essential role during cell development.
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Affiliation(s)
- Luis L Pérez-Mozqueda
- Departamento de Microbiología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, B.C., Mexico
| | - Rafael Vazquez-Duhalt
- Centro de Nanociencias y Nanotecnología (CNyN), Universidad Nacional Autónoma de México (UNAM), Ensenada, Mexico
| | - Ernestina Castro-Longoria
- Departamento de Microbiología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, B.C., Mexico.
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Gu W, Chen K, Zhao X, Geng H, Li J, Qin Y, Bai X, Chang YN, Xia S, Zhang J, Ma S, Wu Z, Xing G, Xing G. Highly Dispersed Fullerenols Hamper Osteoclast Ruffled Border Formation by Perturbing Ca 2+ Bundles. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1802549. [PMID: 30334332 DOI: 10.1002/smll.201802549] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 09/29/2018] [Indexed: 06/08/2023]
Abstract
Osteoporosis, a common and serious bone disorder affecting aged people and postmenopausal women, is characterized by osteoclast overactivity. One therapeutic strategy is suppressing the bone resorption function of hyperactive osteoclasts, but there is no effective drug in clinical practice so far. Herein, it is demonstrated that fullerenols suppress the bone resorption of osteoclasts by inhibiting ruffled borders (RBs) formation. The RBs formation, which is supported by well-aligned actin bundles (B-actins), is a critical event for osteoclast bone resorption. To facilitate this function, osteoclast RBs dynamics is regulated by variable microenvironments to bundle F-actins, protrude cell membrane, and so on. B-actin perturbation by fullerenols is determined here, offering an opportunity to regulate osteoclast function by destroying RBs. In vivo, the therapeutic effect of fullerenols on overactive osteoclasts is confirmed in a mouse model of lipopolysaccharide-induced bone erosion. Collectively, the findings suggest that fullerenols adhere to F-actin surfaces and inhibit RBs formation in osteoclasts, mainly through hampering Ca2+ from bundling F-actins, and this is likely due to the stereo-hindrance effect caused by adherent fullerenols.
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Affiliation(s)
- Weihong Gu
- CAS Key Laboratory for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Kui Chen
- CAS Key Laboratory for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaoyi Zhao
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing, 100049, China
| | - Huan Geng
- Department of Orthopedics, General Hospital of Chinese People's Armed Police Forces, Beijing, 100039, China
| | - Juan Li
- CAS Key Laboratory for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Yanxia Qin
- CAS Key Laboratory for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Xue Bai
- CAS Key Laboratory for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ya-Nan Chang
- CAS Key Laboratory for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Shibo Xia
- CAS Key Laboratory for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jiaxin Zhang
- CAS Key Laboratory for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Sihan Ma
- CAS Key Laboratory for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhonghua Wu
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing, 100049, China
| | - Gengyan Xing
- Department of Orthopedics, General Hospital of Chinese People's Armed Police Forces, Beijing, 100039, China
| | - Gengmei Xing
- CAS Key Laboratory for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
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Lopez BJ, Valentine MT. Molecular control of stress transmission in the microtubule cytoskeleton. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015. [PMID: 26225932 DOI: 10.1016/j.bbamcr.2015.07.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In this article, we will summarize recent progress in understanding the mechanical origins of rigidity, strength, resiliency and stress transmission in the MT cytoskeleton using reconstituted networks formed from purified components. We focus on the role of network architecture, crosslinker compliance and dynamics, and molecular determinants of single filament elasticity, while highlighting open questions and future directions for this work.
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Affiliation(s)
- Benjamin J Lopez
- Department of Mechanical Engineering and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106-5070, USA
| | - Megan T Valentine
- Department of Mechanical Engineering and Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106-5070, USA.
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Uncovering protein polyamination by the spermine-specific antiserum and mass spectrometric analysis. Amino Acids 2014; 47:469-81. [PMID: 25471600 DOI: 10.1007/s00726-014-1879-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 11/18/2014] [Indexed: 01/06/2023]
Abstract
The polyamines spermidine and spermine, and their precursor putrescine, have been shown to play an important role in cell migration, proliferation, and differentiation. Because of their polycationic property, polyamines are traditionally thought to be involved in DNA replication, gene expression, and protein translation. However, polyamines can also be covalently conjugated to proteins by transglutaminase 2 (TG2). This modification leads to an increase in positive charge in the polyamine-incorporated region which significantly alters the structure of proteins. It is anticipated that protein polyamine conjugation may affect the protein-protein interaction, protein localization, and protein function of the TG2 substrates. In order to investigate the roles of polyamine modification, we synthesized a spermine-conjugated antigen and generated an antiserum against spermine. In vitro TG2-catalyzed spermine incorporation assays were carried out to show that actin, tubulins, heat shock protein 70 and five types of histone proteins were modified with spermine, and modification sites were also identified by liquid chromatography and linear ion trap-orbitrap hybrid mass spectrometry. Subsequent mass spectrometry-based shotgun proteomic analysis also identified 254 polyaminated sites in 233 proteins from the HeLa cell lysate catalyzed by human TG2 with spermine, thus allowing, for the first time, a global appraisal of site-specific protein polyamination. Global analysis of mouse tissues showed that this modification really exists in vivo. Importantly, we have demonstrated that there is a new histone modification, polyamination, in cells. However, the functional significance of histone polyamination demands further investigations.
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Janmey PA, Slochower DR, Wang YH, Wen Q, Cēbers A. Polyelectrolyte properties of filamentous biopolymers and their consequences in biological fluids. SOFT MATTER 2014; 10:1439-49. [PMID: 24651463 PMCID: PMC4009494 DOI: 10.1039/c3sm50854d] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Anionic polyelectrolyte filaments are common in biological cells. DNA, RNA, the cytoskeletal filaments F-actin, microtubules, and intermediate filaments, and polysaccharides such as hyaluronan that form the pericellular matrix all have large net negative charge densities distributed over their surfaces. Several filamentous viruses with diameters and stiffnesses similar to those of cytoskeletal polymers also have similar negative charge densities. Extracellular protein filaments such collagen, fibrin and elastin, in contrast, have notably smaller charge densities and do not behave as highly charged polyelectrolytes in solution. This review summarizes data that demonstrate generic counterion-mediated effects on four structurally unrelated biopolymers of similar charge density: F-actin, vimentin, Pf1 virus, and DNA, and explores the possible biological and pathophysiological consequences of the polyelectrolyte properties of biological filaments.
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Affiliation(s)
- Paul A Janmey
- Institute for Medicine and Engineering, University of Pennsylvania, 1010 Vagelos Laboratories, 3340 Smith Walk, Philadelphia, PA 19104, USA
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Abstract
Actin exists as a monomer (G-actin) which can be polymerized to filaments) F-actin) that under the influence of actin-binding proteins and polycations bundle and contribute to the formation of the cytoskeleton. Bundled actin from lysed cells increases the viscosity of sputum in lungs of cystic fibrosis patients. The human host defense peptide LL-37 was previously shown to induce actin bundling and was thus hypothesized to contribute to the pathogenicity of this disease. In this work, interactions between actin and the cationic LL-37 were studied by optical, proteolytic and surface plasmon resonance methods and compared to those obtained with scrambled LL-37 and with the cationic protein lysozyme. We show that LL-37 binds strongly to CaATP-G-actin while scrambled LL-37 does not. While LL-37, at superstoichiometric LL-37/actin concentrations polymerizes MgATP-G-actin, at lower non-polymerizing concentrations LL-37 inhibits actin polymerization by MgCl2 or NaCl. LL-37 bundles Mg-F-actin filaments both at low and physiological ionic strength when in equimolar or higher concentrations than those of actin. The LL-37 induced bundles are significantly less sensitive to increase in ionic strength than those induced by scrambled LL-37 and lysozyme. LL-37 in concentrations lower than those needed for actin polymerization or bundling, accelerates cleavage of both monomer and polymer actin by subtilisin. Our results indicate that the LL-37-actin interaction is partially electrostatic and partially hydrophobic and that a specific actin binding sequence in the peptide is responsible for the hydrophobic interaction. LL-37-induced bundles, which may contribute to the accumulation of sputum in cystic fibrosis, are dissociated very efficiently by DNase-1 and also by cofilin.
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Nguyen LT, Hirst LS. Polymorphism of highly cross-linked F-actin networks: probing multiple length scales. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:031910. [PMID: 21517528 DOI: 10.1103/physreve.83.031910] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 12/20/2010] [Indexed: 05/30/2023]
Abstract
The assembly properties of F-actin filaments in the presence of different biological cross-linker concentrations and types have been investigated using a combined approach of fluorescence confocal microscopy and coarse-grained molecular dynamics simulation. In particular for highly cross-linked regimes, new network morphologies are observed. Complex network formation and the details of the resulting structure are strongly dependent on the ratio of cross-linkers to actin monomers and cross-linker shape but only weakly dependent on overall actin concentration and filament length. The work presented here may help to provide some fundamental understanding of how excessive cross-linkers interact with the actin filament solution, creating different structures in the cell under high cross-linker concentrations. F-actin is not only of biological importance but also, as an example of a semiflexible polymer, has attracted significant interest in its physical behavior. In combination with different cross-linkers semiflexible filaments may provide new routes to bio-materials development and act as the inspiration for new hierarchical network-based materials.
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Affiliation(s)
- Lam T Nguyen
- Department of Physics & MARTECH, Florida State University, Tallahassee, Florida 32306, USA
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Muhlrad A, Grintsevich EE, Reisler E. Polycation induced actin bundles. Biophys Chem 2011; 155:45-51. [PMID: 21411219 DOI: 10.1016/j.bpc.2011.02.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 02/18/2011] [Accepted: 02/19/2011] [Indexed: 01/17/2023]
Abstract
Three polycations, polylysine, the polyamine spermine and the polycationic protein lysozyme were used to study the formation, structure, ionic strength sensitivity and dissociation of polycation-induced actin bundles. Bundles form fast, simultaneously with the polymerization of MgATP-G-actins, upon the addition of polycations to solutions of actins at low ionic strength conditions. This indicates that nuclei and/or nascent filaments bundle due to attractive, electrostatic effect of polycations and the neutralization of repulsive interactions of negative charges on actin. The attractive forces between the filaments are strong, as shown by the low (in nanomolar range) critical concentration of their bundling at low ionic strength. These bundles are sensitive to ionic strength and disassemble partially in 100 mM NaCl, but both the dissociation and ionic strength sensitivity can be countered by higher polycation concentrations. Cys374 residues of actin monomers residing on neighboring filaments in the bundles can be cross-linked by the short span (5.4Å) MTS-1 (1,1-methanedyl bismethanethiosulfonate) cross-linker, which indicates a tight packing of filaments in the bundles. The interfilament cross-links, which connect monomers located on oppositely oriented filaments, prevent disassembly of bundles at high ionic strength. Cofilin and the polysaccharide polyanion heparin disassemble lysozyme induced actin bundles more effectively than the polylysine-induced bundles. The actin-lysozyme bundles are pathologically significant as both proteins are found in the pulmonary airways of cystic fibrosis patients. Their bundles contribute to the formation of viscous mucus, which is the main cause of breathing difficulties and eventual death in this disorder.
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Affiliation(s)
- Andras Muhlrad
- Institute of Dental Sciences, School of Dental Medicine, The Hebrew University, Jerusalem 91120, Israel.
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Wen KK, Rubenstein PA, DeMali KA. Vinculin nucleates actin polymerization and modifies actin filament structure. J Biol Chem 2009; 284:30463-73. [PMID: 19736312 DOI: 10.1074/jbc.m109.021295] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Vinculin links integrins to the actin cytoskeleton by binding F-actin. Little is known with respect to how this interaction occurs or affects actin dynamics. Here we assess the consequence of the vinculin tail (VT) on actin dynamics by examining its binding to monomeric and filamentous yeast actins. VT causes pyrene-labeled G-actin to polymerize in low ionic strength buffer (G-buffer), conditions that normally do not promote actin polymerization. Analysis by electron microscopy shows that, under these conditions, the filaments form small bundles at low VT concentrations, which gradually increase in size until saturation occurs at a ratio of 2 VT:1 actin. Addition of VT to pyrene-labeled mutant yeast G-actin (S265C) produced a fluorescence excimer band, which requires a relatively normal filament geometry. In higher ionic strength polymerization-promoting F-buffer, substoichiometric amounts of VT accelerate the polymerization of pyrene-labeled WT actin. However, the amplitude of the pyrene fluorescence caused by actin polymerization is quenched as the VT concentration increases without an effect on net actin polymerization as determined by centrifugation assays. Finally, addition of VT to preformed pyrene-labeled S265C F-actin causes a concentration-dependent decrease in the maximum amplitude of the pyrene fluorescence band demonstrating the ability of VT to remodel the conformation of the actin filament. These observations support the idea that vinculin can link adhesion plaques to the cytoskeleton by initiating the formation of bundled actin filaments or by remodeling existing filaments.
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Affiliation(s)
- Kuo-Kuang Wen
- Department of Biochemistry, University of Iowa, Roy J and Lucille A Carver College of Medicine, Iowa City, Iowa 52242, USA
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