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Pesquisa : A11.284.430.214.190.750.050 [Categoria DeCS]
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  1 / 10339 MEDLINE  
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[PMID]:29229286
[Au] Autor:Singh RR; Dunn JW; Qadan MM; Hall N; Wang KK; Root DD
[Ad] Endereço:Department of Biological Sciences, Division of Biochemistry and Molecular Biology, University of North Texas, Denton, TX 76203, USA.
[Ti] Título:Whole length myosin binding protein C stabilizes myosin S2 as measured by gravitational force spectroscopy.
[So] Source:Arch Biochem Biophys;638:41-51, 2018 01 15.
[Is] ISSN:1096-0384
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The mechanical stability of the myosin subfragment-2 (S2) was tested with simulated force spectroscopy (SFS) and gravitational force spectroscopy (GFS). Experiments examined unzipping S2, since it required less force than stretching parallel to the coiled coil. Both GFS and SFS demonstrated that the force required to destabilize the light meromyosin (LMM) was greater than the force required to destabilize the coiled coil at each of three different locations along S2. GFS data also conveyed that the mechanical stability of the S2 region is independent from its association with the myosin thick filament using cofilaments of myosin tail and a single intact myosin. The C-terminal end of myosin binding protein C (MyBPC) binds to LMM and the N-terminal end can bind either S2 or actin. The force required to destabilize the myosin coiled coil molecule was 3 times greater in the presence of MyBPC than in its absence. Furthermore, the in vitro motility assay with full length slow skeletal MyBPC slowed down the actin filament sliding over myosin thick filaments. This study demonstrates that skeletal MyBPC both enhanced the mechanical stability of the S2 coiled coil and reduced the sliding velocity of actin filaments over polymerized myosin filaments.
[Mh] Termos MeSH primário: Proteínas de Transporte/química
Subfragmentos de Miosina/química
[Mh] Termos MeSH secundário: Citoesqueleto de Actina/química
Citoesqueleto de Actina/metabolismo
Animais
Proteínas de Transporte/metabolismo
Subfragmentos de Miosina/metabolismo
Domínios Proteicos
Estabilidade Proteica
Coelhos
Análise Espectral
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Carrier Proteins); 0 (Myosin Subfragments); 0 (myosin-binding protein C)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180214
[Lr] Data última revisão:
180214
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171213
[St] Status:MEDLINE


  2 / 10339 MEDLINE  
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[PMID]:29253848
[Au] Autor:McFadden WM; McCall PM; Gardel ML; Munro EM
[Ad] Endereço:Biophysical Sciences Program, University of Chicago, Chicago, Illinois, United States of America.
[Ti] Título:Filament turnover tunes both force generation and dissipation to control long-range flows in a model actomyosin cortex.
[So] Source:PLoS Comput Biol;13(12):e1005811, 2017 12.
[Is] ISSN:1553-7358
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Actomyosin-based cortical flow is a fundamental engine for cellular morphogenesis. Cortical flows are generated by cross-linked networks of actin filaments and myosin motors, in which active stress produced by motor activity is opposed by passive resistance to network deformation. Continuous flow requires local remodeling through crosslink unbinding and and/or filament disassembly. But how local remodeling tunes stress production and dissipation, and how this in turn shapes long range flow, remains poorly understood. Here, we study a computational model for a cross-linked network with active motors based on minimal requirements for production and dissipation of contractile stress: Asymmetric filament compliance, spatial heterogeneity of motor activity, reversible cross-links and filament turnover. We characterize how the production and dissipation of network stress depend, individually, on cross-link dynamics and filament turnover, and how these dependencies combine to determine overall rates of cortical flow. Our analysis predicts that filament turnover is required to maintain active stress against external resistance and steady state flow in response to external stress. Steady state stress increases with filament lifetime up to a characteristic time τm, then decreases with lifetime above τm. Effective viscosity increases with filament lifetime up to a characteristic time τc, and then becomes independent of filament lifetime and sharply dependent on crosslink dynamics. These individual dependencies of active stress and effective viscosity define multiple regimes of steady state flow. In particular our model predicts that when filament lifetimes are shorter than both τc and τm, the dependencies of effective viscosity and steady state stress on filament turnover cancel one another, such that flow speed is insensitive to filament turnover, and shows a simple dependence on motor activity and crosslink dynamics. These results provide a framework for understanding how animal cells tune cortical flow through local control of network remodeling.
[Mh] Termos MeSH primário: Actomiosina/fisiologia
[Mh] Termos MeSH secundário: Citoesqueleto de Actina/química
Citoesqueleto de Actina/fisiologia
Actomiosina/química
Animais
Fenômenos Biomecânicos
Biologia Computacional
Simulação por Computador
Citoesqueleto/fisiologia
Modelos Biológicos
Proteínas Motores Moleculares/química
Proteínas Motores Moleculares/fisiologia
Morfogênese
Reologia
Estresse Fisiológico
Viscosidade
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Molecular Motor Proteins); 9013-26-7 (Actomyosin)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180210
[Lr] Data última revisão:
180210
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171219
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pcbi.1005811


  3 / 10339 MEDLINE  
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[PMID]:29245882
[Au] Autor:Chang M; Oh J; Kim Y; Hohng S; Lee JB
[Ti] Título:Extended depth of field for single biomolecule optical imaging-force spectroscopy.
[So] Source:Opt Express;25(25):32189-32197, 2017 Dec 11.
[Is] ISSN:1094-4087
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Real-time optical imaging combined with single-molecule manipulation broadens the horizons for acquiring information about the spatiotemporal localization and the mechanical details of target molecules. To obtain an optical signal outside the focal plane without unintended interruption of the force signal in single-molecule optical imaging-force spectroscopy, we developed an optical method to extend the depth of field in a high numerical aperture objective (≥ 1.2), required to visualize a single fluorophore. By axial scanning, using an electrically tunable lens with a fixed sample, we were successfully able to visualize the epidermal growth factor receptor (EGFR) moving along the three-dimensionally elongated filamentous actin bundles connecting cells (intercellular nanotube), while another EGFR on the intercellular nanotube was trapped by optical tweezers in living cells. Our approach is simple, fast and inexpensive, but it is powerful for imaging target molecules axially in single-molecule optical imaging-force spectroscopy.
[Mh] Termos MeSH primário: Citoesqueleto de Actina/química
Lentes
Microscopia Confocal/métodos
Microscopia de Fluorescência/métodos
Imagem Óptica/métodos
Pinças Ópticas
Receptor do Fator de Crescimento Epidérmico/análise
Análise Espectral/métodos
[Mh] Termos MeSH secundário: Células HeLa
Seres Humanos
Microscopia de Fluorescência/instrumentação
Nanotubos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
EC 2.7.10.1 (Receptor, Epidermal Growth Factor)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180208
[Lr] Data última revisão:
180208
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171217
[St] Status:MEDLINE
[do] DOI:10.1364/OE.25.032189


  4 / 10339 MEDLINE  
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[PMID]:28469023
[Au] Autor:Tomalka A; Rode C; Schumacher J; Siebert T
[Ad] Endereço:Institute of Sport and Movement Science, University of Stuttgart, Allmandring 28, 70569 Stuttgart, Baden-Württemberg, Germany andre.tomalka@inspo.uni-stuttgart.de.
[Ti] Título:The active force-length relationship is invisible during extensive eccentric contractions in skinned skeletal muscle fibres.
[So] Source:Proc Biol Sci;284(1854), 2017 May 17.
[Is] ISSN:1471-2954
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:In contrast to experimentally observed progressive forces in eccentric contractions, cross-bridge and sliding-filament theories of muscle contraction predict that varying myofilament overlap will lead to increases and decreases in active force during eccentric contractions. Non-cross-bridge contributions potentially explain the progressive total forces. However, it is not clear whether underlying abrupt changes in the slope of the nonlinear force-length relationship are visible in long isokinetic stretches, and in which proportion cross-bridges and non-cross-bridges contribute to muscle force. Here, we show that maximally activated single skinned rat muscle fibres behave (almost across the entire working range) like linear springs. The force slope is about three times the maximum isometric force per optimal length. Cross-bridge and non-cross-bridge contributions to the muscle force were investigated using an actomyosin inhibitor. The experiments revealed a nonlinear progressive contribution of non-cross-bridge forces and suggest a nonlinear cross-bridge contribution similar to the active force-length relationship (though with increased optimal length and maximum isometric force). The linear muscle behaviour might significantly reduce the control effort. Moreover, the observed slight increase in slope with initial length is in accordance with current models attributing the non-cross-bridge force to titin.
[Mh] Termos MeSH primário: Contração Muscular
Fibras Musculares Esqueléticas/fisiologia
Músculo Esquelético/fisiologia
[Mh] Termos MeSH secundário: Citoesqueleto de Actina
Actomiosina/fisiologia
Animais
Conectina/fisiologia
Contração Isométrica
Ratos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Connectin); 9013-26-7 (Actomyosin)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180131
[Lr] Data última revisão:
180131
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170505
[St] Status:MEDLINE


  5 / 10339 MEDLINE  
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[PMID]:29211998
[Au] Autor:Rynkiewicz MJ; Prum T; Hollenberg S; Kiani FA; Fagnant PM; Marston SB; Trybus KM; Fischer S; Moore JR; Lehman W
[Ad] Endereço:Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts.
[Ti] Título:Tropomyosin Must Interact Weakly with Actin to Effectively Regulate Thin Filament Function.
[So] Source:Biophys J;113(11):2444-2451, 2017 Dec 05.
[Is] ISSN:1542-0086
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Elongated tropomyosin, associated with actin-subunits along the surface of thin filaments, makes electrostatic interactions with clusters of conserved residues, K326, K328, and R147, on actin. The association is weak, permitting low-energy cost regulatory movement of tropomyosin across the filament during muscle activation. Interestingly, acidic D292 on actin, also evolutionarily conserved, lies adjacent to the three-residue cluster of basic amino acids and thus may moderate the combined local positive charge, diminishing tropomyosin-actin interaction and facilitating regulatory-switching. Indeed, charge neutralization of D292 is connected to muscle hypotonia in individuals with D292V actin mutations and linked to congenital fiber-type disproportion. Here, the D292V mutation may predispose tropomyosin-actin positioning to a myosin-blocking state, aberrantly favoring muscle relaxation, thus mimicking the low-Ca effect of troponin even in activated muscles. To test this hypothesis, interaction energetics and in vitro function of wild-type and D292V filaments were measured. Energy landscapes based on F-actin-tropomyosin models show the mutation localizes tropomyosin in a blocked-state position on actin defined by a deeper energy minimum, consistent with augmented steric-interference of actin-myosin binding. In addition, whereas myosin-dependent motility of troponin/tropomyosin-free D292V F-actin is normal, motility is dramatically inhibited after addition of tropomyosin to the mutant actin. Thus, D292V-induced blocked-state stabilization appears to disrupt the delicately poised energy balance governing thin filament regulation. Our results validate the premise that stereospecific but necessarily weak binding of tropomyosin to F-actin is required for effective thin filament function.
[Mh] Termos MeSH primário: Citoesqueleto de Actina/metabolismo
Actinas/metabolismo
Tropomiosina/metabolismo
[Mh] Termos MeSH secundário: Actinas/química
Actinas/genética
Cálcio/metabolismo
Seres Humanos
Modelos Moleculares
Mutação
Miosinas/metabolismo
Ligação Proteica
Conformação Proteica em alfa-Hélice
Eletricidade Estática
Termodinâmica
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Actins); 0 (Tropomyosin); EC 3.6.4.1 (Myosins); SY7Q814VUP (Calcium)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180120
[Lr] Data última revisão:
180120
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171207
[St] Status:MEDLINE


  6 / 10339 MEDLINE  
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[PMID]:28743718
[Au] Autor:Stritt S; Beck S; Becker IC; Vögtle T; Hakala M; Heinze KG; Du X; Bender M; Braun A; Lappalainen P; Nieswandt B
[Ad] Endereço:Institute of Experimental Biomedicine I, University Hospital and.
[Ti] Título:Twinfilin 2a regulates platelet reactivity and turnover in mice.
[So] Source:Blood;130(15):1746-1756, 2017 10 12.
[Is] ISSN:1528-0020
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Regulated reorganization of the actin cytoskeleton is a prerequisite for proper platelet production and function. Consequently, defects in proteins controlling actin dynamics have been associated with platelet disorders in humans and mice. Twinfilin 2a (Twf2a) is a small actin-binding protein that inhibits actin filament assembly by sequestering actin monomers and capping filament barbed ends. Moreover, Twf2a binds heterodimeric capping proteins, but the role of this interaction in cytoskeletal dynamics has remained elusive. Even though Twf2a has pronounced effects on actin dynamics in vitro, only little is known about its function in vivo. Here, we report that constitutive Twf2a-deficient mice ( ) display mild macrothrombocytopenia due to a markedly accelerated platelet clearance in the spleen. platelets showed enhanced integrin activation and α-granule release in response to stimulation of (hem) immunoreceptor tyrosine-based activation motif (ITAM) and G-protein-coupled receptors, increased adhesion and aggregate formation on collagen I under flow, and accelerated clot retraction and spreading on fibrinogen. In vivo, Twf2a deficiency resulted in shortened tail bleeding times and faster occlusive arterial thrombus formation. The hyperreactivity of platelets was attributed to enhanced actin dynamics, characterized by an increased activity of n-cofilin and profilin 1, leading to a thickened cortical cytoskeleton and hence sustained integrin activation by limiting calpain-mediated integrin inactivation. In summary, our results reveal the first in vivo functions of mammalian Twf2a and demonstrate that Twf2a-controlled actin rearrangements dampen platelet activation responses in a n-cofilin- and profilin 1-dependent manner, thereby indirectly regulating platelet reactivity and half-life in mice.
[Mh] Termos MeSH primário: Plaquetas/metabolismo
Proteínas dos Microfilamentos/metabolismo
[Mh] Termos MeSH secundário: Citoesqueleto de Actina/metabolismo
Animais
Apoptose
Artérias/patologia
Integrinas/metabolismo
Camundongos
Trombocitopenia/metabolismo
Trombocitopenia/patologia
Trombose/patologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Integrins); 0 (Microfilament Proteins); 0 (TWF2 protein, mouse)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:180116
[Lr] Data última revisão:
180116
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:170727
[St] Status:MEDLINE
[do] DOI:10.1182/blood-2017-02-770768


  7 / 10339 MEDLINE  
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[PMID]:27770373
[Au] Autor:Gómez-Contreras P; Ramiro-Díaz JM; Sierra A; Stipp C; Domann FE; Weigel RJ; Lal G
[Ad] Endereço:Division of Surgical Oncology and Endocrine Surgery, Department of Surgery, University of Iowa, 200 Hawkins Drive, 4641 JCP, Iowa City, IA, 52242, USA.
[Ti] Título:Extracellular matrix 1 (ECM1) regulates the actin cytoskeletal architecture of aggressive breast cancer cells in part via S100A4 and Rho-family GTPases.
[So] Source:Clin Exp Metastasis;34(1):37-49, 2017 01.
[Is] ISSN:1573-7276
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:ECM1 overexpression is an independent predictor of poor prognosis in primary breast carcinomas, however the mechanisms by which ECM1 affects tumor progression have not been completely elucidated. ECM1 was silenced in the triple-negative breast cancer cell lines Hs578T and MDAMB231 using siRNA and the cells were evaluated for changes in morphology, migration, invasion and adhesion. Actin cytoskeleton alterations were evaluated by fluorescent staining and levels of activated Rho GTPases by pull down assays. ECM1 downregulation led to significantly diminished cell migration (p = 0.0005 for Hs578T and p = 0.02 for MDAMB231) and cell adhesion (p < 0.001 for Hs578T and p = 0.01 for MDAMB231). Cell invasion (matrigel) was reduced only in the Hs578T cells (p < 0.01). Silencing decreased the expression of the prometastatic molecules S100A4 and TGFßR2 in both cell lines and CD44 in Hs578T cells. ECM1-silenced cells also exhibited alterations in cell shape and showed bundles of F-actin across the cell (stress fibers) whereas NT-siRNA treated cells showed peripheral membrane ruffling. Downregulation of ECM1 was also associated with an increased F/G actin ratio, when compared to the cells transfected with NT siRNA (p < 0.001 for Hs578T and p < 0.00035 for MDAMB231) and a concomitant decline of activated Rho A in the Hs578T cells. Re-expression of S100A4 in ECM1-silenced cells rescued the phenotype in the Hs578T cells but not the MDAMB231 cells. We conclude that ECM1 is a key player in the metastatic process and regulates the actin cytoskeletal architecture of aggressive breast cancer cells at least in part via alterations in S100A4 and Rho A.
[Mh] Termos MeSH primário: Proteínas da Matriz Extracelular/genética
Proteínas Serina-Treonina Quinases/biossíntese
Receptores de Fatores de Crescimento Transformadores beta/biossíntese
Proteína A4 de Ligação a Cálcio da Família S100/biossíntese
Neoplasias de Mama Triplo Negativas/genética
[Mh] Termos MeSH secundário: Citoesqueleto de Actina/genética
Adesão Celular/genética
Linhagem Celular Tumoral
Movimento Celular/genética
Colágeno
Combinação de Medicamentos
Matriz Extracelular/genética
Proteínas da Matriz Extracelular/biossíntese
Feminino
Regulação Neoplásica da Expressão Gênica
Seres Humanos
Receptores de Hialuronatos/genética
Laminina
Invasividade Neoplásica/genética
Invasividade Neoplásica/patologia
Proteínas Serina-Treonina Quinases/genética
Proteoglicanas
Receptores de Fatores de Crescimento Transformadores beta/genética
Proteína A4 de Ligação a Cálcio da Família S100/genética
Neoplasias de Mama Triplo Negativas/patologia
Proteínas rho de Ligação ao GTP/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Drug Combinations); 0 (ECM1 protein, human); 0 (Extracellular Matrix Proteins); 0 (Hyaluronan Receptors); 0 (Laminin); 0 (Proteoglycans); 0 (Receptors, Transforming Growth Factor beta); 0 (S100 Calcium-Binding Protein A4); 119978-18-6 (matrigel); 142662-27-9 (S100A4 protein, human); 9007-34-5 (Collagen); EC 2.7.11.1 (Protein-Serine-Threonine Kinases); EC 2.7.11.30 (transforming growth factor-beta type II receptor); EC 3.6.5.2 (rho GTP-Binding Proteins)
[Em] Mês de entrada:1703
[Cu] Atualização por classe:180101
[Lr] Data última revisão:
180101
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161023
[St] Status:MEDLINE
[do] DOI:10.1007/s10585-016-9827-5


  8 / 10339 MEDLINE  
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[PMID]:29240845
[Au] Autor:Reimer M; Denby E; Zustiak SP; Schober JM
[Ad] Endereço:Department of Pharmaceutical Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America.
[Ti] Título:Ras GAP-related and C-terminal domain-dependent localization and tumorigenic activities of IQGAP1 in melanoma cells.
[So] Source:PLoS One;12(12):e0189589, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:IQGAP1 interacts with a number of binding partners through a calponin homology domain (CHD), a WW motif, IQ repeats, a Ras GAP-related domain (GRD), and a conserved C-terminal (CT) domain. Among various biological and cellular functions, IQGAP1 is known to play a role in actin cytoskeleton dynamics during membrane ruffling and lamellipodium protrusion. In addition, phosphorylation near the CT domain is thought to control IQGAP1 activity through regulation of intramolecular interaction. In a previous study, we discovered that IQGAP1 preferentially localizes to retracting areas in B16F10 mouse melanoma cells, not areas of membrane ruffling and lamellipodium protrusion. Nothing is known of the domains needed for retraction localization and very little is known of IQGAP1 function in the actin cytoskeleton of melanoma cells. Thus, we examined localization of IQGAP1 mutants to retracting areas, and characterized knock down phenotypes on tissue culture plastic and physiologic-stiffness hydrogels. Localization of IQGAP1 mutants (S1441E/S1443D, S1441A/S1443A, ΔCHD, ΔGRD or ΔCT) to retracting and protruding cell edges were measured. In retracting areas there was a decrease in S1441A/S1443A, ΔGRD and ΔCT localization, a minor decrease in ΔCHD localization, and normal localization of the S1441E/S1443D mutant. In areas of cell protrusion just behind the lamellipodium leading edge, we surprisingly observed both ΔGRD and ΔCT localization, and increased number of microtubules. IQGAP1 knock down caused loss of cell polarity on laminin-coated glass, decreased proliferation on tissue culture polystyrene, and abnormal spheroid growth on laminin-coated hydrogels. We propose that the GRD and CT domains regulate IQGAP1 localization to retracting actin networks to promote a tumorigenic role in melanoma cells.
[Mh] Termos MeSH primário: Melanoma Experimental/metabolismo
Proteínas Ativadoras de ras GTPase/metabolismo
[Mh] Termos MeSH secundário: Citoesqueleto de Actina/metabolismo
Animais
Carcinogênese
Linhagem Celular Tumoral
Técnicas de Silenciamento de Genes
Hidrogéis
Melanoma Experimental/patologia
Camundongos
Microtúbulos/metabolismo
Mutação
Pseudópodes/metabolismo
Proteínas Ativadoras de ras GTPase/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Hydrogels); 0 (IQ motif containing GTPase activating protein 1); 0 (ras GTPase-Activating Proteins)
[Em] Mês de entrada:1712
[Cu] Atualização por classe:171229
[Lr] Data última revisão:
171229
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171215
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0189589


  9 / 10339 MEDLINE  
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[PMID]:28448922
[Au] Autor:Wang Y; Gong J; Wirtz D; Schafer BW
[Ad] Endereço:School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
[Ti] Título:Affine and non-affine deformations quantified in cytoskeletal networks through three-dimensional form-finding model.
[So] Source:J Mech Behav Biomed Mater;72:52-65, 2017 Aug.
[Is] ISSN:1878-0180
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Actin filaments and cross-linkers are main components of cytoskeletal networks in eukaryotic cells, and they support bending moments and axial forces respectively. A three-dimensional form-finding model is proposed in this work to investigate affine and non-affine deformations in cytoskeletal networks. In recent studies, modeling of cytoskeletal networks turns out to be a key piece in the cell mechanics puzzle. We used form-finding analysis to compute and analyze cytoskeletal models. A three-dimensional model is much more flexible and contains more elements than a two-dimensional model, and non-linear finite element analysis is difficult to converge. Thus, vector form intrinsic finite element analysis is employed here for valid results. The three-dimensional model reveals new behaviors beyond earlier two-dimensional models and better aligns with available data. Relative density of actin filaments and height of the form-finding model both play important roles in determining cytoskeletal stiffness, positively and negatively, respectively. Real cytoskeletal networks are quite mixed in terms of affine and non-affine deformations, which are quantified by internal strain energy in actin filaments and cross-linkers. Results are also influenced by actin filament relative density and height of the model. The three-dimensional form-finding model does provide much more room for intensive studies on cytoskeletal networks. In our future study, microtubules, fluidics, viscoelastic-plastic cross-linkers and even the whole cell model may be taken into account gradually to improve the cytoskeletal form-finding model.
[Mh] Termos MeSH primário: Citoesqueleto de Actina/fisiologia
Actinas/fisiologia
[Mh] Termos MeSH secundário: Análise de Elementos Finitos
Seres Humanos
Microtúbulos/fisiologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Actins)
[Em] Mês de entrada:1712
[Cu] Atualização por classe:171225
[Lr] Data última revisão:
171225
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170428
[St] Status:MEDLINE


  10 / 10339 MEDLINE  
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[PMID]:28548701
[Au] Autor:Tonucci FM; Ferretti A; Almada E; Cribb P; Vena R; Hidalgo F; Favre C; Tyska MJ; Kaverina I; Larocca MC
[Ad] Endereço:Instituto de Fisiología Experimental, Consejo de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
[Ti] Título:Microtubules regulate brush border formation.
[So] Source:J Cell Physiol;233(2):1468-1480, 2018 Feb.
[Is] ISSN:1097-4652
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Most epithelial cells contain apical membrane structures associated to bundles of actin filaments, which constitute the brush border. Whereas microtubule participation in the maintenance of the brush border identity has been characterized, their contribution to de novo microvilli organization remained elusive. Hereby, using a cell model of individual enterocyte polarization, we found that nocodazole induced microtubule depolymerization prevented the de novo brush border formation. Microtubule participation in brush border actin organization was confirmed in polarized kidney tubule MDCK cells. We also found that centrosome, but not Golgi derived microtubules, were essential for the initial stages of brush border development. During this process, microtubule plus ends acquired an early asymmetric orientation toward the apical membrane, which clearly differs from their predominant basal orientation in mature epithelia. In addition, overexpression of the microtubule plus ends associated protein CLIP170, which regulate actin nucleation in different cell contexts, facilitated brush border formation. In combination, the present results support the participation of centrosomal microtubule plus ends in the activation of the polarized actin organization associated to brush border formation, unveiling a novel mechanism of microtubule regulation of epithelial polarity.
[Mh] Termos MeSH primário: Colo/fisiologia
Enterócitos/fisiologia
Células Epiteliais/fisiologia
Rim/fisiologia
Microtúbulos/fisiologia
Microvilosidades/fisiologia
[Mh] Termos MeSH secundário: Citoesqueleto de Actina/fisiologia
Animais
Polaridade Celular
Centrômero/fisiologia
Colo/efeitos dos fármacos
Colo/metabolismo
Colo/ultraestrutura
Cães
Enterócitos/efeitos dos fármacos
Enterócitos/metabolismo
Enterócitos/ultraestrutura
Células Epiteliais/efeitos dos fármacos
Células Epiteliais/metabolismo
Células Epiteliais/ultraestrutura
Seres Humanos
Rim/efeitos dos fármacos
Rim/ultraestrutura
Células Madin Darby de Rim Canino
Proteínas Associadas aos Microtúbulos/metabolismo
Microtúbulos/efeitos dos fármacos
Microtúbulos/metabolismo
Microvilosidades/efeitos dos fármacos
Microvilosidades/metabolismo
Nocodazol/farmacologia
Fatores de Tempo
Moduladores de Tubulina/farmacologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Microtubule-Associated Proteins); 0 (Tubulin Modulators); SH1WY3R615 (Nocodazole)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171215
[Lr] Data última revisão:
171215
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170527
[St] Status:MEDLINE
[do] DOI:10.1002/jcp.26033



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