1
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Khudayberdiev S, Weiss K, Heinze A, Colombaretti D, Trausch N, Linne U, Rust MB. The actin-binding protein CAP1 represses MRTF-SRF-dependent gene expression in mouse cerebral cortex. Sci Signal 2024; 17:eadj0032. [PMID: 38713765 DOI: 10.1126/scisignal.adj0032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 04/15/2024] [Indexed: 05/09/2024]
Abstract
Serum response factor (SRF) is an essential transcription factor for brain development and function. Here, we explored how an SRF cofactor, the actin monomer-sensing myocardin-related transcription factor MRTF, is regulated in mouse cortical neurons. We found that MRTF-dependent SRF activity in vitro and in vivo was repressed by cyclase-associated protein CAP1. Inactivation of the actin-binding protein CAP1 reduced the amount of actin monomers in the cytoplasm, which promoted nuclear MRTF translocation and MRTF-SRF activation. This function was independent of cofilin1 and actin-depolymerizing factor, and CAP1 loss of function in cortical neurons was not compensated by endogenous CAP2. Transcriptomic and proteomic analyses of cerebral cortex lysates from wild-type and Cap1 knockout mice supported the role of CAP1 in repressing MRTF-SRF-dependent signaling in vivo. Bioinformatic analysis identified likely MRTF-SRF target genes, which aligned with the transcriptomic and proteomic results. Together with our previous studies that implicated CAP1 in axonal growth cone function as well as the morphology and plasticity of excitatory synapses, our findings establish CAP1 as a crucial actin regulator in the brain relevant for formation of neuronal networks.
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Affiliation(s)
- Sharof Khudayberdiev
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, Hans-Meerwein-Strasse 6, 35032 Marburg, Germany
| | - Kerstin Weiss
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Anika Heinze
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Dalila Colombaretti
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Nathan Trausch
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Uwe Linne
- Department of Chemistry, Philipps-University Marburg, 35032 Marburg, Germany
| | - Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, Hans-Meerwein-Strasse 6, 35032 Marburg, Germany
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2
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Moss A, Kuttippurathu L, Srivastava A, Schwaber JS, Vadigepalli R. Dynamic dysregulation of transcriptomic networks in brainstem autonomic nuclei during hypertension development in the female spontaneously hypertensive rat. Physiol Genomics 2024; 56:283-300. [PMID: 38145287 DOI: 10.1152/physiolgenomics.00073.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 12/17/2023] [Accepted: 12/19/2023] [Indexed: 12/26/2023] Open
Abstract
Neurogenic hypertension stems from an imbalance in autonomic function that shifts the central cardiovascular control circuits toward a state of dysfunction. Using the female spontaneously hypertensive rat and the normotensive Wistar-Kyoto rat model, we compared the transcriptomic changes in three autonomic nuclei in the brainstem, nucleus of the solitary tract (NTS), caudal ventrolateral medulla, and rostral ventrolateral medulla (RVLM) in a time series at 8, 10, 12, 16, and 24 wk of age, spanning the prehypertensive stage through extended chronic hypertension. RNA-sequencing data were analyzed using an unbiased, dynamic pattern-based approach that uncovered dominant and several subtle differential gene regulatory signatures. Our results showed a persistent dysregulation across all three autonomic nuclei regardless of the stage of hypertension development as well as a cascade of transient dysregulation beginning in the RVLM at the prehypertensive stage that shifts toward the NTS at the hypertension onset. Genes that were persistently dysregulated were heavily enriched for immunological processes such as antigen processing and presentation, the adaptive immune response, and the complement system. Genes with transient dysregulation were also largely region-specific and were annotated for processes that influence neuronal excitability such as synaptic vesicle release, neurotransmitter transport, and an array of neuropeptides and ion channels. Our results demonstrate that neurogenic hypertension is characterized by brainstem region-specific transcriptomic changes that are highly dynamic with significant gene regulatory changes occurring at the hypertension onset as a key time window for dysregulation of homeostatic processes across the autonomic control circuits.NEW & NOTEWORTHY Hypertension is a major disease and is the primary risk factor for cardiovascular complications and stroke. The gene expression changes in the central nervous system circuits driving hypertension are understudied. Here, we show that coordinated and region-specific gene expression changes occur in the brainstem autonomic circuits over time during the development of a high blood pressure phenotype in a rat model of human essential hypertension.
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Affiliation(s)
- Alison Moss
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
| | - Lakshmi Kuttippurathu
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
| | - Ankita Srivastava
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
| | - James S Schwaber
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
| | - Rajanikanth Vadigepalli
- Daniel Baugh Institute for Functional Genomics and Computational Biology, Department of Pathology and Genomic Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
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Francis CR, Bell ML, Skripnichuk MM, Kushner EJ. Arf6 is required for endocytosis and filamentous actin assembly during angiogenesis in vitro. Microcirculation 2023; 30:e12831. [PMID: 37750425 PMCID: PMC10688150 DOI: 10.1111/micc.12831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/24/2023] [Accepted: 09/13/2023] [Indexed: 09/27/2023]
Abstract
OBJECTIVE Endocytosis is a process vital to angiogenesis and vascular homeostasis. In pathologies where supraphysiological growth factor signaling underlies disease etiology, such as in diabetic retinopathy and solid tumors, strategies to limit chronic growth factor signaling by way of blunting endocytic processes have been shown to have tremendous clinical value. ADP ribosylation factor 6 (Arf6) is a small GTPase that promotes the assembly of actin necessary for clathrin-mediated and clathrin-independent endocytosis. In its absence, growth factor signaling is greatly diminished, which has been shown to ameliorate pathological signaling input in diseased vasculature. However, it is less clear if there are bystander effects related to loss of Arf6 on angiogenic behaviors. Our goal was to provide an analysis of Arf6's function in angiogenic endothelium, focusing on its role in actin and endocytosis as well as sprouting morphogenesis. METHODS Primary endothelial cells were cultured in both 2D and 3D environments. Here, endothelial cells were fixed and stained for various proteins or transfected with fluorescently-tagged constructs for live-cell imaging. RESULTS We found that Arf6 localized to both filamentous actin and sites of endocytosis in two-dimensional culture. Loss of Arf6 distorted both apicobasal polarity and reduced the total cellular filamentous actin content, which may be the primary driver underlying gross sprouting dysmorphogenesis in its absence. CONCLUSIONS Our findings highlight that endothelial Arf6 is a potent mediator of both actin regulation and endocytosis and is required for proper sprout formation.
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Affiliation(s)
| | - Makenzie L. Bell
- Department of Biological Sciences, University of Denver, Denver, CO
| | | | - Erich J. Kushner
- Department of Biological Sciences, University of Denver, Denver, CO
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Chen X, Li Y, Guo M, Xu B, Ma Y, Zhu H, Feng XQ. Polymerization force-regulated actin filament-Arp2/3 complex interaction dominates self-adaptive cell migrations. Proc Natl Acad Sci U S A 2023; 120:e2306512120. [PMID: 37639611 PMCID: PMC10483647 DOI: 10.1073/pnas.2306512120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 07/23/2023] [Indexed: 08/31/2023] Open
Abstract
Cells migrate by adapting their leading-edge behaviors to heterogeneous extracellular microenvironments (ECMs) during cancer invasions and immune responses. Yet it remains poorly understood how such complicated dynamic behaviors emerge from millisecond-scale assembling activities of protein molecules, which are hard to probe experimentally. To address this gap, we establish a spatiotemporal "resistance-adaptive propulsion" theory based on the interactions between Arp2/3 complexes and polymerizing actin filaments and a multiscale dynamic modeling system spanning from molecular proteins to the cell. We quantitatively find that cells can accurately self-adapt propulsive forces to overcome heterogeneous ECMs via a resistance-triggered positive feedback mechanism, dominated by polymerization-induced actin filament bending and the bending-regulated actin-Arp2/3 binding. However, for high resistance regions, resistance triggers a negative feedback, hindering branched filament assembly, which adapts cellular morphologies to circumnavigate the obstacles. Strikingly, the synergy of the two opposite feedbacks not only empowers the cell with both powerful and flexible migratory capabilities to deal with complex ECMs but also enables efficient utilization of intracellular proteins by the cell. In addition, we identify that the nature of cell migration velocity depending on ECM history stems from the inherent temporal hysteresis of cytoskeleton remodeling. We also show that directional cell migration is dictated by the competition between the local stiffness of ECMs and the local polymerizing rate of actin network caused by chemotactic cues. Our results reveal that it is the polymerization force-regulated actin filament-Arp2/3 complex binding interaction that dominates self-adaptive cell migrations in complex ECMs, and we provide a predictive theory and a spatiotemporal multiscale modeling system at the protein level.
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Affiliation(s)
- Xindong Chen
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing100084, China
- School of Engineering, Cardiff University, CardiffCF24 3AA, United Kingdom
| | - Yuhui Li
- CytoMorpho Lab, Laboratoire de Physiologie Cellulaire et Végétale, Interdisciplinary Research Institute of Grenoble, Commissariat à l’Énergie Atomique et aux Énergies Alternatives/CNRS/Université Grenoble Alpes, Grenoble38054, France
| | - Ming Guo
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Bowen Xu
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing100084, China
| | - Yanhui Ma
- School of Engineering, Cardiff University, CardiffCF24 3AA, United Kingdom
| | - Hanxing Zhu
- School of Engineering, Cardiff University, CardiffCF24 3AA, United Kingdom
| | - Xi-Qiao Feng
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing100084, China
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Polina I, Mishra J, Cypress MW, Landherr M, Valkov N, Chaput I, Nieto B, Mende U, Zhang P, Jhun BS, O-Uchi J. Mitochondrial Ca 2+ uniporter (MCU) variants form plasma-membrane channels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.31.551242. [PMID: 37577584 PMCID: PMC10418069 DOI: 10.1101/2023.07.31.551242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
MCU is widely recognized as a responsible gene for encoding a pore-forming subunit of highly mitochondrial-specific and Ca 2+ -selective channel, mitochondrial Ca 2+ uniporter complex (mtCUC). Here, we report a novel short variant derived from the MCU gene (termed MCU-S) which lacks mitochondria-targeted sequence and forms a Ca 2+ - permeable channel outside of mitochondria. MCU-S was ubiquitously expressed in all cell-types/tissues, with particularly high expression in human platelets. MCU-S formed Ca 2+ channels at the plasma membrane, which exhibited similar channel properties to those observed in mtCUC. MCU-S channels at the plasma membrane served as an additional Ca 2+ influx pathway for platelet activation. Our finding is completely distinct from the originally reported MCU gene function and provides novel insights into the molecular basis of MCU variant-dependent cellular Ca 2+ handling.
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6
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Zuo Y, Mei X, Singson A. CRISPR/Cas9 Mediated Fluorescent Tagging of Caenorhabditis elegans SPE-38 Reveals a Complete Localization Pattern in Live Spermatozoa. Biomolecules 2023; 13:biom13040623. [PMID: 37189371 DOI: 10.3390/biom13040623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/22/2023] [Accepted: 03/27/2023] [Indexed: 04/01/2023] Open
Abstract
The Caenorhabditis elegans spe-38 gene encodes a four-pass transmembrane molecule that is required in sperm for fertilization. In previous work, the localization of the SPE-38 protein was examined using polyclonal antibodies on spermatids and mature amoeboid spermatozoa. SPE-38 is localized to unfused membranous organelles (MOs) in nonmotile spermatids. Different fixation conditions revealed that SPE-38 either localized to fused MOs and the cell body plasma membrane or the pseudopod plasma membrane of mature sperm. To address this localization paradox in mature sperm, CRISPR/Cas9 genome editing was used to tag endogenous SPE-38 with fluorescent wrmScarlet-I. Homozygous male and hermaphrodite worms encoding SPE-38::wrmScarlet-I were fertile indicating the fluorescent tag does not interfere with SPE-38 function during sperm activation or fertilization. We found that SPE-38::wrmScarlet-I localized to MOs in spermatids consistent with previous antibody localization. In mature and motile spermatozoa we found SPE-38::wrmScarlet-I in fused MOs, the cell body plasma membrane, and the pseudopod plasma membrane. We conclude that the localization pattern observed with SPE-38::wrmScarlet-I represents the complete distribution of SPE-38 in mature spermatozoa and this localization pattern is consistent with a hypothesized role of SPE-38 directly in sperm-egg binding and/or fusion.
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Hennlein L, Ghanawi H, Gerstner F, Palominos García E, Yildirim E, Saal-Bauernschubert L, Moradi M, Deng C, Klein T, Appenzeller S, Sauer M, Briese M, Simon C, Sendtner M, Jablonka S. Plastin 3 rescues cell surface translocation and activation of TrkB in spinal muscular atrophy. J Cell Biol 2023; 222:e202204113. [PMID: 36607273 PMCID: PMC9827530 DOI: 10.1083/jcb.202204113] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 10/12/2022] [Accepted: 12/08/2022] [Indexed: 01/07/2023] Open
Abstract
Plastin 3 (PLS3) is an F-actin-bundling protein that has gained attention as a modifier of spinal muscular atrophy (SMA) pathology. SMA is a lethal pediatric neuromuscular disease caused by loss of or mutations in the Survival Motor Neuron 1 (SMN1) gene. Pathophysiological hallmarks are cellular maturation defects of motoneurons prior to degeneration. Despite the observed beneficial modifying effect of PLS3, the mechanism of how it supports F-actin-mediated cellular processes in motoneurons is not yet well understood. Our data reveal disturbed F-actin-dependent translocation of the Tropomyosin receptor kinase B (TrkB) to the cell surface of Smn-deficient motor axon terminals, resulting in reduced TrkB activation by its ligand brain-derived neurotrophic factor (BDNF). Improved actin dynamics by overexpression of hPLS3 restores membrane recruitment and activation of TrkB and enhances spontaneous calcium transients by increasing Cav2.1/2 "cluster-like" formations in SMA axon terminals. Thus, our study provides a novel role for PLS3 in supporting correct alignment of transmembrane proteins, a key mechanism for (moto)-neuronal development.
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Affiliation(s)
- Luisa Hennlein
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Hanaa Ghanawi
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Florian Gerstner
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig, Germany
| | | | - Ezgi Yildirim
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | | | - Mehri Moradi
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Chunchu Deng
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Teresa Klein
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Silke Appenzeller
- Comprehensive Cancer Center Mainfranken; Core Unit Bioinformatics, University Hospital Würzburg, Würzburg, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Michael Briese
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Christian Simon
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig, Germany
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Sibylle Jablonka
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
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8
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Francis CR, Bell ML, Skripnichuk MM, Kushner EJ. Arf6 Regulates Endocytosis and Angiogenesis by Promoting Filamentous Actin Assembly. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.22.529543. [PMID: 36865161 PMCID: PMC9980066 DOI: 10.1101/2023.02.22.529543] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Clathrin-mediated endocytosis (CME) is a process vital to angiogenesis as well as general vascular homeostasis. In pathologies where supraphysiological growth factor signaling underlies disease etiology, such as in diabetic retinopathy and solid tumors, strategies to limit chronic growth factor signaling by way of CME have been shown to have tremendous clinical value. ADP ribosylation factor 6 (Arf6) is a small GTPase that promotes the assembly of actin necessary for CME. In its absence, growth factor signaling is greatly diminished, which has been shown to ameliorate pathological signaling input in diseased vasculature. However, it is less clear if there are bystander effects related to loss of Arf6 on angiogenic behaviors. Our goal was to provide a analysis of Arf6’s function in angiogenic endothelium, focusing on its role in lumenogenesis as well as its relation to actin and CME. We found that Arf6 localized to both filamentous actin and sites of CME in 2-dimensional culture. Loss of Arf6 distorted both apicobasal polarity and reduced the total cellular filamentous actin content, and this may be the primary driver underlying gross dysmorphogenesis during angiogenic sprouting in its absence. Our findings highlight that endothelial Arf6 is a potent mediator of both actin regulation and CME.
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Affiliation(s)
| | - Makenzie L. Bell
- Department of Biological Sciences, University of Denver, Denver, CO
| | | | - Erich J. Kushner
- Department of Biological Sciences, University of Denver, Denver, CO
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Zhang X, Han J, Fan D, Wang J, Lin X, Zhang H, Zhang C, Bai J, Huang H, Gu Y. Lysine-40 succinylation of TAGLN2 induces glioma angiogenesis and tumor growth through regulating TMSB4X. Cancer Gene Ther 2023; 30:172-181. [PMID: 36131066 DOI: 10.1038/s41417-022-00534-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 08/12/2022] [Accepted: 09/06/2022] [Indexed: 01/19/2023]
Abstract
Protein lysine succinylation (Ksucc) represents an important regulatory mechanism of tumor development. In this work, the difference of protein Ksucc between HCMEC/D3 co-cultured with U87 (glioma endothelia cells, GEC) and without U87 (normal endothelia cells, NEC) was investigated using TMT labeling and affinity enrichment followed by high-resolution LC-MS/MS analysis. Interestingly, TAGLN2 was highly succinylated at K40 in GEC (15.36 folds vs. NEC). Compared to the Vector group, TAGLN2WT and a succinylation-mimetic TAGLN2K40E greatly promoted the angiogenesis of glioma in vitro and in vivo. Furthermore, the adhesion and metastasis of U87 co-cultured with GEC in the TAGLN2WT or TAGLN2K40E group were also significantly promoted. This was consistent with the increased expression of VE-cadherin and actin cytoskeleton remodeling induced by TAGLN2 K40succ in GEC. In addition, high K40succ of TAGLN2 was associated with poor prognosis in patients with glioma. Overexpression of TAGLN2K40E also markedly promoted the proliferation and migration of glioma cells, further analysis of in vivo xenograft tumors showed that there was a significant decrease in tumor size and angiogenesis in the TAGLN2K40R group. Notably, the co-localization of TMSB4X and TAGLN2 mainly in the nucleus and cytoplasm of glioma cells was detected by immunofluorescence staining. We identified TMSB4X as a potential target of TAGLN2, which was proved to interact with TAGLN2WT rather than TAGLN2K40A. And the inhibition of TMSB4X could markedly attenuate the proliferation and migration of glioma cells induced by TAGLN2 K40succ. The results revealed K40succ of TAGLN2 could be a novelty diagnosis and therapeutic target for gliomas.
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Affiliation(s)
- Xiaoyi Zhang
- Department of Pharmacology, Life Science and Biopharmaceutical Institution, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning Province, P. R. China
| | - Jin Han
- Department of Pharmacology, Life Science and Biopharmaceutical Institution, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning Province, P. R. China
| | - Di Fan
- Department of Neurosurgery, General Hospital of Northern Theater Command, Shenyang, P. R. China
| | - Jiahong Wang
- Department of Pharmacology, Life Science and Biopharmaceutical Institution, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning Province, P. R. China
| | - Xiangdan Lin
- Department of Neurosurgery, General Hospital of Northern Theater Command, Shenyang, P. R. China
| | - Hong Zhang
- Department of Pharmacology, Life Science and Biopharmaceutical Institution, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning Province, P. R. China
| | - Cai Zhang
- Department of Pharmacology, Life Science and Biopharmaceutical Institution, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning Province, P. R. China
| | - Jialing Bai
- Department of Pharmacology, Life Science and Biopharmaceutical Institution, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning Province, P. R. China
| | - Hailan Huang
- Department of Pharmacology, Life Science and Biopharmaceutical Institution, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning Province, P. R. China
| | - Yanting Gu
- Department of Pharmacology, Life Science and Biopharmaceutical Institution, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning Province, P. R. China.
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10
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Schneider F, Metz I, Rust MB. Regulation of actin filament assembly and disassembly in growth cone motility and axon guidance. Brain Res Bull 2023; 192:21-35. [PMID: 36336143 DOI: 10.1016/j.brainresbull.2022.10.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022]
Abstract
Directed outgrowth of axons is fundamental for the establishment of neuronal networks. Axon outgrowth is guided by growth cones, highly motile structures enriched in filamentous actin (F-actin) located at the axons' distal tips. Growth cones exploit F-actin-based protrusions to scan the environment for guidance cues, and they contain the sensory apparatus to translate guidance cue information into intracellular signaling cascades. These cascades act upstream of actin-binding proteins (ABP) and thereby control assembly and disassembly of F-actin. Spatiotemporally controlled F-actin dis-/assembly in growth cones steers the axon towards attractants and away from repellents, and it thereby navigates the axon through the developing nervous system. Hence, ABP that control F-actin dynamics emerged as critical regulators of neuronal network formation. In the present review article, we will summarize and discuss current knowledge of the mechanisms that control remodeling of the actin cytoskeleton in growth cones, focusing on recent progress in the field. Further, we will introduce tools and techniques that allow to study actin regulatory mechanism in growth cones.
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Affiliation(s)
- Felix Schneider
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany; DFG Research Training Group 'Membrane Plasticity in Tissue Development and Remodeling', GRK 2213, Philipps-University of Marburg, 35032 Marburg, Germany; Molecular Urooncology, Department of Urology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Isabell Metz
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany; DFG Research Training Group 'Membrane Plasticity in Tissue Development and Remodeling', GRK 2213, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany; DFG Research Training Group 'Membrane Plasticity in Tissue Development and Remodeling', GRK 2213, Philipps-University of Marburg, 35032 Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032 Marburg, Germany.
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11
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Li Y, Wang D, Ge H, Güngör C, Gong X, Chen Y. Cytoskeletal and Cytoskeleton-Associated Proteins: Key Regulators of Cancer Stem Cell Properties. Pharmaceuticals (Basel) 2022; 15:1369. [PMID: 36355541 PMCID: PMC9698833 DOI: 10.3390/ph15111369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 11/02/2022] [Accepted: 11/06/2022] [Indexed: 08/08/2023] Open
Abstract
Cancer stem cells (CSCs) are a subpopulation of cancer cells possessing stemness characteristics that are closely associated with tumor proliferation, recurrence and resistance to therapy. Recent studies have shown that different cytoskeletal components and remodeling processes have a profound impact on the behavior of CSCs. In this review, we outline the different cytoskeletal components regulating the properties of CSCs and discuss current and ongoing therapeutic strategies targeting the cytoskeleton. Given the many challenges currently faced in targeted cancer therapy, a deeper comprehension of the molecular events involved in the interaction of the cytoskeleton and CSCs will help us identify more effective therapeutic strategies to eliminate CSCs and ultimately improve patient survival.
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Affiliation(s)
- Yuqiang Li
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- NHC Key Laboratory of Cancer Proteomics, Laboratory of Structural Biology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Dan Wang
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- Department of General Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Heming Ge
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- Department of General Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Cenap Güngör
- Department of General Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Xuejun Gong
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Yongheng Chen
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, China
- NHC Key Laboratory of Cancer Proteomics, Laboratory of Structural Biology, Xiangya Hospital, Central South University, Changsha 410008, China
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Francis CR, Kincross H, Kushner EJ. Rab35 governs apicobasal polarity through regulation of actin dynamics during sprouting angiogenesis. Nat Commun 2022; 13:5276. [PMID: 36075898 PMCID: PMC9458672 DOI: 10.1038/s41467-022-32853-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 08/17/2022] [Indexed: 12/01/2022] Open
Abstract
In early blood vessel development, trafficking programs, such as those using Rab GTPases, are tasked with delivering vesicular cargo with high spatiotemporal accuracy. However, the function of many Rab trafficking proteins remain ill-defined in endothelial tissue; therefore, their relevance to blood vessel development is unknown. Rab35 has been shown to play an enigmatic role in cellular behaviors which differs greatly between tissue-type and organism. Importantly, Rab35 has never been characterized for its potential contribution in sprouting angiogenesis; thus, our goal was to map Rab35’s primary function in angiogenesis. Our results demonstrate that Rab35 is critical for sprout formation; in its absence, apicobasal polarity is entirely lost in vitro and in vivo. To determine mechanism, we systematically explored established Rab35 effectors and show that none are operative in endothelial cells. However, we find that Rab35 partners with DENNd1c, an evolutionarily divergent guanine exchange factor, to localize to actin. Here, Rab35 regulates actin polymerization through limiting Rac1 and RhoA activity, which is required to set up proper apicobasal polarity during sprout formation. Our findings establish that Rab35 is a potent brake of actin remodeling during blood vessel development. The promiscuous GTPase Rab35 has been shown to be involved in many important cellular functions. In this article, Francis et al. illustrate how Rab35 acts as a critical brake to actin remodeling during sprouting angiogenesis and how it is necessary for proper blood vessel development.
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Affiliation(s)
- Caitlin R Francis
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Hayle Kincross
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Erich J Kushner
- Department of Biological Sciences, University of Denver, Denver, CO, USA.
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13
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Pimm ML, Liu X, Tuli F, Heritz J, Lojko A, Henty-Ridilla JL. Visualizing molecules of functional human profilin. eLife 2022; 11:e76485. [PMID: 35666129 PMCID: PMC9249392 DOI: 10.7554/elife.76485] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 06/06/2022] [Indexed: 11/20/2022] Open
Abstract
Profilin-1 (PFN1) is a cytoskeletal protein that regulates the dynamics of actin and microtubule assembly. Thus, PFN1 is essential for the normal division, motility, and morphology of cells. Unfortunately, conventional fusion and direct labeling strategies compromise different facets of PFN1 function. As a consequence, the only methods used to determine known PFN1 functions have been indirect and often deduced in cell-free biochemical assays. We engineered and characterized two genetically encoded versions of tagged PFN1 that behave identical to each other and the tag-free protein. In biochemical assays purified proteins bind to phosphoinositide lipids, catalyze nucleotide exchange on actin monomers, stimulate formin-mediated actin filament assembly, and bound tubulin dimers (kD = 1.89 µM) to impact microtubule dynamics. In PFN1-deficient mammalian cells, Halo-PFN1 or mApple-PFN1 (mAp-PEN1) restored morphological and cytoskeletal functions. Titrations of self-labeling Halo-ligands were used to visualize molecules of PFN1. This approach combined with specific function-disrupting point-mutants (Y6D and R88E) revealed PFN1 bound to microtubules in live cells. Cells expressing the ALS-associated G118V disease variant did not associate with actin filaments or microtubules. Thus, these tagged PFN1s are reliable tools for studying the dynamic interactions of PFN1 with actin or microtubules in vitro as well as in important cell processes or disease-states.
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Affiliation(s)
- Morgan L Pimm
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Xinbei Liu
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Farzana Tuli
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Jennifer Heritz
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Ashley Lojko
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Jessica L Henty-Ridilla
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
- Department of Neuroscience and Physiology, SUNY Upstate Medical UniversitySyracuseUnited States
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14
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Rempel SK, Welch MJ, Ludwig AL, Phillips MJ, Kancherla Y, Zack DJ, Gamm DM, Gómez TM. Human photoreceptors switch from autonomous axon extension to cell-mediated process pulling during synaptic marker redistribution. Cell Rep 2022; 39:110827. [PMID: 35584680 DOI: 10.1016/j.celrep.2022.110827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 03/18/2022] [Accepted: 04/26/2022] [Indexed: 11/19/2022] Open
Abstract
Photoreceptors (PRs) are the primary visual sensory cells, and their loss leads to blindness that is currently incurable. Although cell replacement therapy holds promise, success is hindered by our limited understanding of PR axon growth during development and regeneration. Here, we generate retinal organoids from human pluripotent stem cells to study the mechanisms of PR process extension. We find that early-born PRs exhibit autonomous axon extension from dynamic terminals. However, as PRs age from 40 to 80 days of differentiation, they lose dynamic terminals on 2D substrata and in 3D retinal organoids. Interestingly, PRs without motile terminals are still capable of extending axons but only by process stretching via attachment to motile non-PR cells. Immobile PR terminals of late-born PRs have fewer and less organized actin filaments but more synaptic proteins compared with early-born PR terminals. These findings may help inform the development of PR transplantation therapies.
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Affiliation(s)
- Sarah K Rempel
- Department of Neuroscience, University of Wisconsin - Madison, Madison, WI 53706, USA; McPherson Eye Research Institute, University of Wisconsin - Madison, Madison, WI 53706, USA
| | - Madalynn J Welch
- Department of Neuroscience, University of Wisconsin - Madison, Madison, WI 53706, USA
| | - Allison L Ludwig
- Department of Ophthalmology and Visual Sciences, University of Wisconsin - Madison, Madison, WI 53705, USA; McPherson Eye Research Institute, University of Wisconsin - Madison, Madison, WI 53706, USA; Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - M Joseph Phillips
- McPherson Eye Research Institute, University of Wisconsin - Madison, Madison, WI 53706, USA; Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Yochana Kancherla
- Department of Neuroscience, University of Wisconsin - Madison, Madison, WI 53706, USA
| | - Donald J Zack
- Department of Ophthalmology, Johns Hopkins University, Baltimore, MD 21287, USA
| | - David M Gamm
- Department of Ophthalmology and Visual Sciences, University of Wisconsin - Madison, Madison, WI 53705, USA; McPherson Eye Research Institute, University of Wisconsin - Madison, Madison, WI 53706, USA; Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Timothy M Gómez
- Department of Neuroscience, University of Wisconsin - Madison, Madison, WI 53706, USA; McPherson Eye Research Institute, University of Wisconsin - Madison, Madison, WI 53706, USA.
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15
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Liu X, Pimm ML, Haarer B, Brawner AT, Henty-Ridilla JL. Biochemical characterization of actin assembly mechanisms with ALS-associated profilin variants. Eur J Cell Biol 2022; 101:151212. [PMID: 35248815 PMCID: PMC10163920 DOI: 10.1016/j.ejcb.2022.151212] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/23/2022] [Accepted: 02/25/2022] [Indexed: 12/26/2022] Open
Abstract
Eight separate mutations in the actin-binding protein profilin-1 have been identified as a rare cause of amyotrophic lateral sclerosis (ALS). Profilin is essential for many neuronal cell processes through its regulation of lipids, nuclear signals, and cytoskeletal dynamics, including actin filament assembly. Direct interactions between profilin and actin monomers inhibit actin filament polymerization. In contrast, profilin can also stimulate polymerization by simultaneously binding actin monomers and proline-rich tracts found in other proteins. Whether the ALS-associated mutations in profilin compromise these actin assembly functions is unclear. We performed a quantitative biochemical comparison of the direct and formin mediated impact for the eight ALS-associated profilin variants on actin assembly using classic protein-binding and single-filament microscopy assays. We determined that the binding constant of each profilin for actin monomers generally correlates with the actin nucleation strength associated with each ALS-related profilin. In the presence of formin, the A20T, R136W, Q139L, and C71G variants failed to activate the elongation phase of actin assembly. This diverse range of formin-activities is not fully explained through profilin-poly-L-proline (PLP) interactions, as all ALS-associated variants bind a formin-derived PLP peptide with similar affinities. However, chemical denaturation experiments suggest that the folding stability of these profilins impact some of these effects on actin assembly. Thus, changes in profilin protein stability and alterations in actin filament polymerization may both contribute to the profilin-mediated actin disruptions in ALS.
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Affiliation(s)
- Xinbei Liu
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Morgan L Pimm
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Brian Haarer
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Andrew T Brawner
- Department of Neuroscience & Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Jessica L Henty-Ridilla
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Department of Neuroscience & Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
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16
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Oxidative Stress Modulation by Carnosine in Scaffold Free Human Dermis Spheroids Model: A Proteomic Study. Int J Mol Sci 2022; 23:ijms23031468. [PMID: 35163388 PMCID: PMC8836079 DOI: 10.3390/ijms23031468] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/23/2022] [Accepted: 01/25/2022] [Indexed: 12/11/2022] Open
Abstract
Carnosine is an endogenous β-alanyl-L-histidine dipeptide endowed with antioxidant and carbonyl scavenger properties, which is able to significantly prevent the visible signs of aging and photoaging. To investigate the mechanism of action of carnosine on human skin proteome, a 3D scaffold-free spheroid model of primary dermal fibroblasts from a 50-year-old donor was adopted in combination with quantitative proteomics for the first time. The label free proteomics approach based on high-resolution mass spectrometry, integrated with network analyses, provided a highly sensitive and selective method to describe the human dermis spheroid model during long-term culture and upon carnosine treatment. Overall, 2171 quantified proteins allowed the in-depth characterization of the 3D dermis phenotype during growth and differentiation, at 14 versus 7 days of culture. A total of 485 proteins were differentially regulated by carnosine at 7 days, an intermediate time of culture. Of the several modulated pathways, most are involved in mitochondrial functionality, such as oxidative phosphorylation, TCA cycle, extracellular matrix reorganization and apoptosis. In long-term culture, functional modules related to oxidative stress were upregulated, inducing the aging process of dermis spheroids, while carnosine treatment prevented this by the downregulation of the same functional modules. The application of quantitative proteomics, coupled to advanced and relevant in vitro scaffold free spheroids, represents a new concrete application for personalized therapies and a novel care approach.
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17
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Dynamics of the Actin Cytoskeleton at Adhesion Complexes. BIOLOGY 2021; 11:biology11010052. [PMID: 35053050 PMCID: PMC8773209 DOI: 10.3390/biology11010052] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/22/2021] [Accepted: 12/24/2021] [Indexed: 01/06/2023]
Abstract
The shape of cells is altered to allow cells to adapt to their changing environments, including responding to internally generated and externally applied force. Force is sensed by cell surface adhesion proteins that are enriched in sites where cells bind to the extracellular matrix (focal adhesions) and neighboring cells (cell-cell or adherens junctions). Receptors at these adhesion sites stimulate intracellular signal transduction cascades that culminate in dramatic changes in the actin cytoskeleton. New actin filaments form, and/or new and existing filaments can be cleaved, branched, or bundled. Here, we discuss the actin cytoskeleton and its functions. We will examine the current understanding for how the actin cytoskeleton is tethered to adhesion sites. Finally, we will highlight recent studies describing how the actin cytoskeleton at these adhesion sites is remodeled in response to force.
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18
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Edwards P, Skruber K, Milićević N, Heidings JB, Read TA, Bubenik P, Vitriol EA. TDAExplore: Quantitative analysis of fluorescence microscopy images through topology-based machine learning. PATTERNS 2021; 2:100367. [PMID: 34820649 PMCID: PMC8600226 DOI: 10.1016/j.patter.2021.100367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/31/2021] [Accepted: 09/20/2021] [Indexed: 11/02/2022]
Abstract
Recent advances in machine learning have greatly enhanced automatic methods to extract information from fluorescence microscopy data. However, current machine-learning-based models can require hundreds to thousands of images to train, and the most readily accessible models classify images without describing which parts of an image contributed to classification. Here, we introduce TDAExplore, a machine learning image analysis pipeline based on topological data analysis. It can classify different types of cellular perturbations after training with only 20–30 high-resolution images and performs robustly on images from multiple subjects and microscopy modes. Using only images and whole-image labels for training, TDAExplore provides quantitative, spatial information, characterizing which image regions contribute to classification. Computational requirements to train TDAExplore models are modest and a standard PC can perform training with minimal user input. TDAExplore is therefore an accessible, powerful option for obtaining quantitative information about imaging data in a wide variety of applications. TDAExplore combines topological data analysis with machine learning classification As few as 20–30 high-resolution images can be used to train TDAExplore models TDAExplore is robust to different microscopy modes, dataset size, image features TDAExplore quantifies where and how much each image resembles the training data
Traditional intensity-based measurements of fluorescent microscopy data limit its potential to reveal new information about its sample. Here, we present an image analysis pipeline called TDAExplore, which is based on topological data analysis and machine learning classification. In addition to being highly accurate in assigning images to their correct group, TDAExplore quantifies how much images resemble the training data and identifies which parts are different, an improvement over other machine learning models that do not permit insight into how classification tasks were made. The next steps for TDAExplore will be to expand its capabilities into three-dimensional, multivariate, and time series datasets. This work represents progress into a future where machine learning identifies and describes nuanced image features in ways that allow researchers to answer important biological questions and generate new hypotheses for future studies.
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19
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Murk K, Ornaghi M, Schiweck J. Profilin Isoforms in Health and Disease - All the Same but Different. Front Cell Dev Biol 2021; 9:681122. [PMID: 34458253 PMCID: PMC8387879 DOI: 10.3389/fcell.2021.681122] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 07/12/2021] [Indexed: 12/11/2022] Open
Abstract
Profilins are small actin binding proteins, which are structurally conserved throughout evolution. They are probably best known to promote and direct actin polymerization. However, they also participate in numerous cell biological processes beyond the roles typically ascribed to the actin cytoskeleton. Moreover, most complex organisms express several profilin isoforms. Their cellular functions are far from being understood, whereas a growing number of publications indicate that profilin isoforms are involved in the pathogenesis of various diseases. In this review, we will provide an overview of the profilin family and "typical" profilin properties including the control of actin dynamics. We will then discuss the profilin isoforms of higher animals in detail. In terms of cellular functions, we will focus on the role of Profilin 1 (PFN1) and Profilin 2a (PFN2a), which are co-expressed in the central nervous system. Finally, we will discuss recent findings that link PFN1 and PFN2a to neurological diseases, such as amyotrophic lateral sclerosis (ALS), Fragile X syndrome (FXS), Huntington's disease and spinal muscular atrophy (SMA).
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Affiliation(s)
- Kai Murk
- Institute of Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Marta Ornaghi
- Institute of Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Juliane Schiweck
- Institute of Biochemistry, Charité Universitätsmedizin Berlin, Berlin, Germany
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20
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Sharma VP, Williams J, Leung E, Sanders J, Eddy R, Castracane J, Oktay MH, Entenberg D, Condeelis JS. SUN-MKL1 Crosstalk Regulates Nuclear Deformation and Fast Motility of Breast Carcinoma Cells in Fibrillar ECM Microenvironment. Cells 2021; 10:1549. [PMID: 34205257 PMCID: PMC8234170 DOI: 10.3390/cells10061549] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 06/16/2021] [Indexed: 12/14/2022] Open
Abstract
Aligned collagen fibers provide topography for the rapid migration of single tumor cells (streaming migration) to invade the surrounding stroma, move within tumor nests towards blood vessels to intravasate and form distant metastases. Mechanisms of tumor cell motility have been studied extensively in the 2D context, but the mechanistic understanding of rapid single tumor cell motility in the in vivo context is still lacking. Here, we show that streaming tumor cells in vivo use collagen fibers with diameters below 3 µm. Employing 1D migration assays with matching in vivo fiber dimensions, we found a dependence of tumor cell motility on 1D substrate width, with cells moving the fastest and the most persistently on the narrowest 1D fibers (700 nm-2.5 µm). Interestingly, we also observed nuclear deformation in the absence of restricting extracellular matrix pores during high speed carcinoma cell migration in 1D, similar to the nuclear deformation observed in tumor cells in vivo. Further, we found that actomyosin machinery is aligned along the 1D axis and actomyosin contractility synchronously regulates cell motility and nuclear deformation. To further investigate the link between cell speed and nuclear deformation, we focused on the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex proteins and SRF-MKL1 signaling, key regulators of mechanotransduction, actomyosin contractility and actin-based cell motility. Analysis of The Cancer Genome Atlas dataset showed a dramatic decrease in the LINC complex proteins SUN1 and SUN2 in primary tumor compared to the normal tissue. Disruption of LINC complex by SUN1 + 2 KD led to multi-lobular elongated nuclei, increased tumor cell motility and concomitant increase in F-actin, without affecting Lamin proteins. Mechanistically, we found that MKL1, an effector of changes in cellular G-actin to F-actin ratio, is required for increased 1D motility seen in SUN1 + 2 KD cells. Thus, we demonstrate a previously unrecognized crosstalk between SUN proteins and MKL1 transcription factor in modulating nuclear shape and carcinoma cell motility in an in vivo relevant 1D microenvironment.
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Affiliation(s)
- Ved P. Sharma
- Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (E.L.); (R.E.); (M.H.O.); (D.E.)
- Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - James Williams
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA; (J.W.); (J.S.); (J.C.)
| | - Edison Leung
- Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (E.L.); (R.E.); (M.H.O.); (D.E.)
| | - Joe Sanders
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA; (J.W.); (J.S.); (J.C.)
| | - Robert Eddy
- Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (E.L.); (R.E.); (M.H.O.); (D.E.)
| | - James Castracane
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA; (J.W.); (J.S.); (J.C.)
| | - Maja H. Oktay
- Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (E.L.); (R.E.); (M.H.O.); (D.E.)
- Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Integrated Imaging Program, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - David Entenberg
- Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (E.L.); (R.E.); (M.H.O.); (D.E.)
- Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Integrated Imaging Program, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - John S. Condeelis
- Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (E.L.); (R.E.); (M.H.O.); (D.E.)
- Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Integrated Imaging Program, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Surgery, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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21
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Gübeli RJ, Bertoldo D, Shimada K, Gerhold CB, Hurst V, Takahashi Y, Harada K, Mothukuri GK, Wilbs J, Harata M, Gasser SM, Heinis C. In Vitro-Evolved Peptides Bind Monomeric Actin and Mimic Actin-Binding Protein Thymosin-β4. ACS Chem Biol 2021; 16:820-828. [PMID: 33843189 DOI: 10.1021/acschembio.0c00825] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Actin is the most abundant protein in eukaryotic cells and is key to many cellular functions. The filamentous form of actin (F-actin) can be studied with help of natural products that specifically recognize it, as for example fluorophore-labeled probes of the bicyclic peptide phalloidin, but no synthetic probes exist for the monomeric form of actin (G-actin). Herein, we have panned a phage display library consisting of more than 10 billion bicyclic peptides against G-actin and isolated binders with low nanomolar affinity and greater than 1000-fold selectivity over F-actin. Sequence analysis revealed a strong similarity to a region of thymosin-β4, a protein that weakly binds G-actin, and competition binding experiments confirmed a common binding region at the cleft between actin subdomains 1 and 3. Together with F-actin-specific peptides that we also isolated, we evaluated the G-actin peptides as probes in pull-down, imaging, and competition binding experiments. While the F-actin peptides were applied successfully for capturing actin in cell lysates and for imaging, the G-actin peptides did not bind in the cellular context, most likely due to competition with thymosin-β4 or related endogenous proteins for the same binding site.
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Affiliation(s)
- Raphael J. Gübeli
- Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Davide Bertoldo
- Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Kenji Shimada
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Christian B. Gerhold
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Verena Hurst
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
- Faculty of Natural Sciences, University of Basel, 4056 Basel, Switzerland
| | - Yuichiro Takahashi
- Laboratory of Molecular Biology, Tohoku University, Tsutsumidori-Amamiyamachi 1-1, Aoba-ku, Sendai 981-8555, Japan
| | - Kai Harada
- Laboratory of Molecular Biology, Tohoku University, Tsutsumidori-Amamiyamachi 1-1, Aoba-ku, Sendai 981-8555, Japan
| | - Ganesh K. Mothukuri
- Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Jonas Wilbs
- Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Masahiko Harata
- Laboratory of Molecular Biology, Tohoku University, Tsutsumidori-Amamiyamachi 1-1, Aoba-ku, Sendai 981-8555, Japan
| | - Susan M. Gasser
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
- Faculty of Natural Sciences, University of Basel, 4056 Basel, Switzerland
| | - Christian Heinis
- Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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22
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Yu J, Oentaryo MJ, Lee CW. Local protein synthesis of neuronal MT1-MMP for agrin-induced presynaptic development. Development 2021; 148:268316. [PMID: 34015092 DOI: 10.1242/dev.199000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 05/02/2021] [Indexed: 01/15/2023]
Abstract
Upon the stimulation of extracellular cues, a significant number of proteins are synthesized distally along the axon. Although local protein synthesis is crucial for various stages throughout neuronal development, its involvement in presynaptic differentiation at developing neuromuscular junctions remains unknown. By using axon severing and microfluidic chamber assays, we first showed that treatment of a protein synthesis inhibitor, cycloheximide, inhibits agrin-induced presynaptic differentiation in cultured Xenopus spinal neurons. Newly synthesized proteins are prominently detected, as revealed by the staining of click-reactive cell-permeable puromycin analog O-propargyl-puromycin, at agrin bead-neurite contacts involving the mTOR/4E-BP1 pathway. Next, live-cell time-lapse imaging demonstrated the local capturing and immobilization of ribonucleoprotein granules upon agrin bead stimulation. Given that our recent study reported the roles of membrane-type 1 matrix metalloproteinase (MT1-MMP) in agrin-induced presynaptic differentiation, here we further showed that MT1-MMP mRNA is spatially enriched and locally translated at sites induced by agrin beads. Taken together, this study reveals an essential role for axonal MT1-MMP translation, on top of the well-recognized long-range transport of MT1-MMP proteins synthesized from neuronal cell bodies, in mediating agrin-induced presynaptic differentiation.
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Affiliation(s)
- Jun Yu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Marilyn Janice Oentaryo
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Chi Wai Lee
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
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23
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Abstract
A new study reports that the actin-monomer-binding protein profilin 1 dictates protrusion character at the cell edge. These findings help explain how distinct, tunable actin polymerization pathways collaborate to form higher-order cellular structures.
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24
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Pinto-Costa R, Sousa SC, Leite SC, Nogueira-Rodrigues J, Ferreira da Silva T, Machado D, Marques J, Costa AC, Liz MA, Bartolini F, Brites P, Costell M, Fässler R, Sousa MM. Profilin 1 delivery tunes cytoskeletal dynamics toward CNS axon regeneration. J Clin Invest 2020; 130:2024-2040. [PMID: 31945017 DOI: 10.1172/jci125771] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/14/2020] [Indexed: 12/12/2022] Open
Abstract
After trauma, regeneration of adult CNS axons is abortive, causing devastating neurologic deficits. Despite progress in rehabilitative care, there is no effective treatment that stimulates axonal growth following injury. Using models with different regenerative capacities, followed by gain- and loss-of-function analysis, we identified profilin 1 (Pfn1) as a coordinator of actin and microtubules (MTs), powering axonal growth and regeneration. In growth cones, Pfn1 increased actin retrograde flow, MT growth speed, and invasion of filopodia by MTs, orchestrating cytoskeletal dynamics toward axonal growth. In vitro, active Pfn1 promoted MT growth in a formin-dependent manner, whereas localization of MTs to growth cone filopodia was facilitated by direct MT binding and interaction with formins. In vivo, Pfn1 ablation limited regeneration of growth-competent axons after sciatic nerve and spinal cord injury. Adeno-associated viral (AAV) delivery of constitutively active Pfn1 to rodents promoted axonal regeneration, neuromuscular junction maturation, and functional recovery of injured sciatic nerves, and increased the ability of regenerating axons to penetrate the inhibitory spinal cord glial scar. Thus, we identify Pfn1 as an important regulator of axonal regeneration and suggest that AAV-mediated delivery of constitutively active Pfn1, together with the identification of modulators of Pfn1 activity, should be considered to treat the injured nervous system.
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Affiliation(s)
- Rita Pinto-Costa
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and.,Graduate Program in Molecular and Cell Biology, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Sara C Sousa
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and.,Graduate Program in Molecular and Cell Biology, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Sérgio C Leite
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and
| | - Joana Nogueira-Rodrigues
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and.,Graduate Program in Molecular and Cell Biology, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Tiago Ferreira da Silva
- NeuroLipid Biology Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, Universidade do Porto, Porto, Portugal
| | - Diana Machado
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and
| | - Joana Marques
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and
| | - Ana Catarina Costa
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and
| | - Márcia A Liz
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and
| | - Francesca Bartolini
- Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
| | - Pedro Brites
- NeuroLipid Biology Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, Universidade do Porto, Porto, Portugal
| | - Mercedes Costell
- Department of Biochemistry and Molecular Biology and Estructura de Reserca Interdisciplinar en Biotecnologia i Biomedicina, Universitat de València, Valencia, Spain
| | - Reinhard Fässler
- Department of Molecular Medicine, Max Plank Institute of Biochemistry, Martinsried, Germany
| | - Mónica M Sousa
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and
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25
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Leite SC, Pinto-Costa R, Sousa MM. Actin dynamics in the growth cone: a key player in axon regeneration. Curr Opin Neurobiol 2020; 69:11-18. [PMID: 33359956 DOI: 10.1016/j.conb.2020.11.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 01/01/2023]
Abstract
Neuronal development, maintenance and function depends on the tight regulation of cytoskeleton organization and dynamics. Following injury, adult central nervous system neurons have a limited ability to regenerate and to recapitulate their robust developmental axon growth. This decreased regenerative capacity is set by their inability to establish regeneration-competent growth cones. Growth cones are actin-enriched structures that regulate axon extension rate and direction. During neuronal development, increasing actin dynamics in the growth cone through the regulation of the activity of specific actin-binding proteins leads to increased axon elongation. Here, we will focus on recent findings showing that enhanced axon regeneration in the adult nervous system can be achieved by promoting actin dynamics, or by decreasing actomyosin contraction in the growth cone. These discoveries underscore the importance of actin organization in the growth cone as a key factor to promote axon (re)growth that should be further explored in the future.
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Affiliation(s)
- Sérgio Carvalho Leite
- Institute of Psychiatry and Neurosciences of Paris, INSERM U1266, Université de Paris, 75014 Paris, France
| | - Rita Pinto-Costa
- Nerve Regeneration Group, i3S- Instituto de Investigação e Inovação em Saúde and IBMC- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Monica Mendes Sousa
- Nerve Regeneration Group, i3S- Instituto de Investigação e Inovação em Saúde and IBMC- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
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26
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Padmanabhan K, Grobe H, Cohen J, Soffer A, Mahly A, Adir O, Zaidel-Bar R, Luxenburg C. Thymosin β4 is essential for adherens junction stability and epidermal planar cell polarity. Development 2020; 147:dev.193425. [PMID: 33310787 PMCID: PMC7758630 DOI: 10.1242/dev.193425] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 10/27/2020] [Indexed: 01/19/2023]
Abstract
Planar cell polarity (PCP) is essential for tissue morphogenesis and homeostasis; however, the mechanisms that orchestrate the cell shape and packing dynamics required to establish PCP are poorly understood. Here, we identified a major role for the globular (G)-actin-binding protein thymosin-β4 (TMSB4X) in PCP establishment and cell adhesion in the developing epidermis. Depletion of Tmsb4x in mouse embryos hindered eyelid closure and hair-follicle angling owing to PCP defects. Tmsb4x depletion did not preclude epidermal cell adhesion in vivo or in vitro; however, it resulted in abnormal structural organization and stability of adherens junction (AJ) due to defects in filamentous (F)-actin and G-actin distribution. In cultured keratinocytes, TMSB4X depletion increased the perijunctional G/F-actin ratio and decreased G-actin incorporation into junctional actin networks, but it did not change the overall actin expression level or cellular F-actin content. A pharmacological treatment that increased the G/F-actin ratio and decreased actin polymerization mimicked the effects of Tmsb4x depletion on both AJs and PCP. Our results provide insights into the regulation of the actin pool and its involvement in AJ function and PCP establishment. Highlighted Article: By regulating actin pool distribution and incorporation into junctional actin networks, thymosin β4 regulates cell–cell adhesion, planar cell polarity and epidermal morphogenesis.
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Affiliation(s)
- Krishnanand Padmanabhan
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv 69978, Israel
| | - Hanna Grobe
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv 69978, Israel
| | - Jonathan Cohen
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv 69978, Israel
| | - Arad Soffer
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv 69978, Israel
| | - Adnan Mahly
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv 69978, Israel
| | - Orit Adir
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv 69978, Israel
| | - Ronen Zaidel-Bar
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv 69978, Israel
| | - Chen Luxenburg
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, P.O. Box 39040, Tel Aviv 69978, Israel
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27
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Pollitt SL, Myers KR, Yoo J, Zheng JQ. LIM and SH3 protein 1 localizes to the leading edge of protruding lamellipodia and regulates axon development. Mol Biol Cell 2020; 31:2718-2732. [PMID: 32997597 PMCID: PMC7927181 DOI: 10.1091/mbc.e20-06-0366] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The actin cytoskeleton drives cell motility and is essential for neuronal development and function. LIM and SH3 protein 1 (LASP1) is a unique actin-binding protein that is expressed in a wide range of cells including neurons, but its roles in cellular motility and neuronal development are not well understood. We report that LASP1 is expressed in rat hippocampus early in development, and this expression is maintained through adulthood. High-resolution imaging reveals that LASP1 is selectively concentrated at the leading edge of lamellipodia in migrating cells and axonal growth cones. This local enrichment of LASP1 is dynamically associated with the protrusive activity of lamellipodia, depends on the barbed ends of actin filaments, and requires both the LIM domain and the nebulin repeats of LASP1. Knockdown of LASP1 in cultured rat hippocampal neurons results in a substantial reduction in axonal outgrowth and arborization. Finally, loss of the Drosophila homologue Lasp from a subset of commissural neurons in the developing ventral nerve cord produces defasciculated axon bundles that do not reach their targets. Together, our data support a novel role for LASP1 in actin-based lamellipodial protrusion and establish LASP1 as a positive regulator of both in vitro and in vivo axon development.
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Affiliation(s)
| | | | - Jin Yoo
- Emory College, Emory University, Atlanta, GA 30322
| | - James Q Zheng
- Department of Cell Biology and.,Department of Neurology and Center for Neurodegenerative Diseases, Emory University School of Medicine, and
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28
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Skruber K, Warp PV, Shklyarov R, Thomas JD, Swanson MS, Henty-Ridilla JL, Read TA, Vitriol EA. Arp2/3 and Mena/VASP Require Profilin 1 for Actin Network Assembly at the Leading Edge. Curr Biol 2020; 30:2651-2664.e5. [PMID: 32470361 DOI: 10.1016/j.cub.2020.04.085] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 03/09/2020] [Accepted: 04/29/2020] [Indexed: 12/27/2022]
Abstract
Cells have many types of actin structures, which must assemble from a common monomer pool. Yet, it remains poorly understood how monomers are distributed to and shared between different filament networks. Simplified model systems suggest that monomers are limited and heterogeneous, which alters actin network assembly through biased polymerization and internetwork competition. However, less is known about how monomers influence complex actin structures, where different networks competing for monomers overlap and are functionally interdependent. One example is the leading edge of migrating cells, which contains filament networks generated by multiple assembly factors. The leading edge dynamically switches between the formation of different actin structures, such as lamellipodia or filopodia, by altering the balance of these assembly factors' activities. Here, we sought to determine how the monomer-binding protein profilin 1 (PFN1) controls the assembly and organization of actin in mammalian cells. Actin polymerization in PFN1 knockout cells was severely disrupted, particularly at the leading edge, where both Arp2/3 and Mena/VASP-based filament assembly was inhibited. Further studies showed that in the absence of PFN1, Arp2/3 no longer localizes to the leading edge and Mena/VASP is non-functional. Additionally, we discovered that discrete stages of internetwork competition and collaboration between Arp2/3 and Mena/VASP networks exist at different PFN1 concentrations. Low levels of PFN1 caused filopodia to form exclusively at the leading edge, while higher concentrations inhibited filopodia and favored lamellipodia and pre-filopodia bundles. These results demonstrate that dramatic changes to actin architecture can be made simply by modifying PFN1 availability.
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Affiliation(s)
- Kristen Skruber
- Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Peyton V Warp
- Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Rachael Shklyarov
- Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - James D Thomas
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Jessica L Henty-Ridilla
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, NY 13210, USA
| | - Tracy-Ann Read
- Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Eric A Vitriol
- Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, College of Medicine, Gainesville, FL 32610, USA.
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29
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Abstract
Cell migration is an essential process, both in unicellular organisms such as amoeba and as individual or collective motility in highly developed multicellular organisms like mammals. It is controlled by a variety of activities combining protrusive and contractile forces, normally generated by actin filaments. Here, we summarize actin filament assembly and turnover processes, and how respective biochemical activities translate into different protrusion types engaged in migration. These actin-based plasma membrane protrusions include actin-related protein 2/3 complex-dependent structures such as lamellipodia and membrane ruffles, filopodia as well as plasma membrane blebs. We also address observed antagonisms between these protrusion types, and propose a model - also inspired by previous literature - in which a complex balance between specific Rho GTPase signaling pathways dictates the protrusion mechanism employed by cells. Furthermore, we revisit published work regarding the fascinating antagonism between Rac and Rho GTPases, and how this intricate signaling network can define cell behavior and modes of migration. Finally, we discuss how the assembly of actin filament networks can feed back onto their regulators, as exemplified for the lamellipodial factor WAVE regulatory complex, tightly controlling accumulation of this complex at specific subcellular locations as well as its turnover.
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30
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Schill Y, Bijata M, Kopach O, Cherkas V, Abdel-Galil D, Böhm K, Schwab MH, Matsuda M, Compan V, Basu S, Bijata K, Wlodarczyk J, Bard L, Cole N, Dityatev A, Zeug A, Rusakov DA, Ponimaskin E. Serotonin 5-HT 4 receptor boosts functional maturation of dendritic spines via RhoA-dependent control of F-actin. Commun Biol 2020; 3:76. [PMID: 32060357 PMCID: PMC7021812 DOI: 10.1038/s42003-020-0791-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/23/2020] [Indexed: 01/24/2023] Open
Abstract
Activity-dependent remodeling of excitatory connections underpins memory formation in the brain. Serotonin receptors are known to contribute to such remodeling, yet the underlying molecular machinery remains poorly understood. Here, we employ high-resolution time-lapse FRET imaging in neuroblastoma cells and neuronal dendrites to establish that activation of serotonin receptor 5-HT4 (5-HT4R) rapidly triggers spatially-restricted RhoA activity and G13-mediated phosphorylation of cofilin, thus locally boosting the filamentous actin fraction. In neuroblastoma cells, this leads to cell rounding and neurite retraction. In hippocampal neurons in situ, 5-HT4R-mediated RhoA activation triggers maturation of dendritic spines. This is paralleled by RhoA-dependent, transient alterations in cell excitability, as reflected by increased spontaneous synaptic activity, apparent shunting of evoked synaptic responses, and enhanced long-term potentiation of excitatory transmission. The 5-HT4R/G13/RhoA signaling thus emerges as a previously unrecognized molecular pathway underpinning use-dependent functional remodeling of excitatory synaptic connections.
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Affiliation(s)
- Yvonne Schill
- Cellular Neurophysiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany
| | - Monika Bijata
- Cellular Neurophysiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteur Str. 3, 02-093, Warsaw, Poland
| | - Olga Kopach
- UCL Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Volodymyr Cherkas
- Cellular Neurophysiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany
| | - Dalia Abdel-Galil
- Cellular Neurophysiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany
| | - Katrin Böhm
- German Center for Neurodegenerative Diseases (DZNE), Leipziger Str. 44, 39120, Magdeburg, Germany
| | - Markus H Schwab
- Cellular Neurophysiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany
| | - Michiyuki Matsuda
- Bioimaging and Cell Signaling, Kyoto University, Kyoto, 606-8501, Japan
| | | | - Subhadip Basu
- Cellular Neurophysiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany
- Computer Science and Engineering, Jadavpur University, Kolkata, 700032, India
| | - Krystian Bijata
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteur Str. 3, 02-093, Warsaw, Poland
| | - Jakub Wlodarczyk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteur Str. 3, 02-093, Warsaw, Poland
| | - Lucie Bard
- UCL Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Nicholas Cole
- UCL Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Alexander Dityatev
- German Center for Neurodegenerative Diseases (DZNE), Leipziger Str. 44, 39120, Magdeburg, Germany
- Medical Faculty, Otto-von-Guericke-University, Magdeburg, Leipziger Str. 44, 39120, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Andre Zeug
- Cellular Neurophysiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany
| | - Dmitri A Rusakov
- UCL Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Evgeni Ponimaskin
- Cellular Neurophysiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany.
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31
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Faust JJ, Millis BA, Tyska MJ. Profilin-Mediated Actin Allocation Regulates the Growth of Epithelial Microvilli. Curr Biol 2019; 29:3457-3465.e3. [PMID: 31607529 DOI: 10.1016/j.cub.2019.08.051] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 07/17/2019] [Accepted: 08/20/2019] [Indexed: 01/18/2023]
Abstract
Transporting epithelial cells, like those that line the intestinal tract, are specialized for solute processing and uptake. One defining feature is the brush border, an array of microvilli that serves to amplify apical membrane surface area and increase functional capacity. During differentiation, upon exit from stem-cell-containing crypts, enterocytes build thousands of microvilli, each supported by a parallel bundle of actin filaments several microns in length. Given the high concentration of actin residing in mature brush borders, we sought to determine whether enterocytes were resource (i.e., actin monomer) limited in assembling this domain. To examine this possibility, we inhibited Arp2/3, the ubiquitous branched actin nucleator, to increase G-actin availability during brush border assembly. In native intestinal tissues, Arp2/3 inhibition led to increased microvilli length on the surface of crypt, but not villus, enterocytes. In a cell culture model of brush border assembly, Arp2/3 inhibition accelerated the growth and increased the length of microvilli; it also led to a redistribution of F-actin from cortical lateral networks into the brush border. Effects on brush border growth were rescued by treatment with the G-actin sequestering drug, latrunculin A. G-actin binding protein, profilin-1, colocalized in the terminal web with G-actin, and knockdown of this factor compromised brush border growth in a concentration-dependent manner. Finally, the acceleration in brush border assembly induced by Arp2/3 inhibition was abrogated by profilin-1 knockdown. Thus, brush border assembly is limited by G-actin availability, and profilin-1 directs unallocated actin monomers into microvillar core bundles during enterocyte differentiation.
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Affiliation(s)
- James J Faust
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Bryan A Millis
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Biomedical Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA; Cell Imaging Shared Resource, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Vanderbilt Biophotonics Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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32
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Sukumar UK, Packirisamy G. Fabrication of Nanofibrous Scaffold Grafted with Gelatin Functionalized Polystyrene Microspheres for Manifesting Nanomechanical Cues of Stretch Stimulated Fibroblast. ACS APPLIED BIO MATERIALS 2019; 2:5323-5339. [DOI: 10.1021/acsabm.9b00580] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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33
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Brettle M, Stefen H, Djordjevic A, Fok SYY, Chan JW, van Hummel A, van der Hoven J, Przybyla M, Volkerling A, Ke YD, Delerue F, Ittner LM, Fath T. Developmental Expression of Mutant PFN1 in Motor Neurons Impacts Neuronal Growth and Motor Performance of Young and Adult Mice. Front Mol Neurosci 2019; 12:231. [PMID: 31611772 PMCID: PMC6776973 DOI: 10.3389/fnmol.2019.00231] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/10/2019] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease with limited treatment and no cure. Mutations in profilin 1 were identified as a cause of familial ALS (fALS) in 2012. We investigated the functional impact of mutant profilin 1 expression in spinal cords during mouse development. We developed a novel mouse model with the expression of profilin 1 C71G under the control of the Hb9 promoter, targeting expression to α-motor neurons in the spinal cord during development. Embryos of transgenic mice showed evidence of a significant reduction of brachial nerve diameter and a loss of Mendelian inheritance. Despite the lack of transgene expression, adult mice presented with significant motor deficits. Transgenic mice had a significant reduction in the number of motor neurons in the spinal cord. Further analysis of these motor neurons in aged transgenic mice revealed reduced levels of TDP-43 and ChAT expression. Although profilin 1 C71G was only expressed during development, adult mice presented with some ALS-associated pathology and motor symptoms. This study highlights the effect of profilin 1 during neurodevelopment and the impact that this may have in later ALS.
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Affiliation(s)
- Merryn Brettle
- School of Medical Sciences, Faculty of Medicine, UNSW Sydney, Randwick, NSW, Australia.,Biomedical Imaging Facility, Mark Wainwright Analytical Centre, UNSW Sydney, Randwick, NSW, Australia
| | - Holly Stefen
- Dementia Research Centre and Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Aleksandra Djordjevic
- School of Medical Sciences, Faculty of Medicine, UNSW Sydney, Randwick, NSW, Australia
| | - Sandra Y Y Fok
- School of Medical Sciences, Faculty of Medicine, UNSW Sydney, Randwick, NSW, Australia.,Biomedical Imaging Facility, Mark Wainwright Analytical Centre, UNSW Sydney, Randwick, NSW, Australia
| | - Josephine W Chan
- School of Medical Sciences, Faculty of Medicine, UNSW Sydney, Randwick, NSW, Australia
| | - Annika van Hummel
- Dementia Research Centre and Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Julia van der Hoven
- Dementia Research Centre and Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Magdalena Przybyla
- Dementia Research Centre and Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Alexander Volkerling
- School of Medical Sciences, Faculty of Medicine, UNSW Sydney, Randwick, NSW, Australia
| | - Yazi D Ke
- Dementia Research Centre and Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Fabien Delerue
- Dementia Research Centre and Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Lars M Ittner
- Dementia Research Centre and Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Thomas Fath
- School of Medical Sciences, Faculty of Medicine, UNSW Sydney, Randwick, NSW, Australia.,Dementia Research Centre and Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
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34
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Yamashiro S, Watanabe N. Quantitative high-precision imaging of myosin-dependent filamentous actin dynamics. J Muscle Res Cell Motil 2019; 41:163-173. [PMID: 31313218 DOI: 10.1007/s10974-019-09541-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/10/2019] [Indexed: 12/20/2022]
Abstract
Over recent decades, considerable effort has been made to understand how mechanical stress applied to the actin network alters actin assembly and disassembly dynamics. However, there are conflicting reports concerning the issue both in vitro and in cells. In this review, we discuss concerns regarding previous quantitative live-cell experiments that have attempted to evaluate myosin regulation of filamentous actin (F-actin) turnover. In particular, we highlight an error-generating mechanism in quantitative live-cell imaging, namely convection-induced misdistribution of actin-binding probes. Direct observation of actin turnover at the single-molecule level using our improved electroporation-based Single-Molecule Speckle (eSiMS) microscopy technique overcomes these concerns. We introduce our recent single-molecule analysis that unambiguously demonstrates myosin-dependent regulation of F-actin stability in live cells. We also discuss the possible application of eSiMS microscopy in the analysis of actin remodeling in striated muscle cells.
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Affiliation(s)
- Sawako Yamashiro
- Laboratory of Single-Molecule Cell Biology, Kyoto University Graduate School of Biostudies, Yoshida Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan. .,Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| | - Naoki Watanabe
- Laboratory of Single-Molecule Cell Biology, Kyoto University Graduate School of Biostudies, Yoshida Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan.,Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan
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35
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Chakrabarty N, Jung P. Stochastic models of polymerization-based axonal actin transport. Phys Biol 2019; 16:056001. [PMID: 31195374 DOI: 10.1088/1478-3975/ab29cd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Recent advances in live cell imaging of F-actin structures, combined with pulse-chase imaging and computational modeling have suggested that actin is transported along the axon via biased polymerization of metastable actin fibers (actin trails). This mechanism is distinct from motor driven polymer transport, such as for neurofilaments and can be best described as molecular hitchhiking, where G-actin molecules are intermittently incorporated into actin fibers which grow preferentially in the anterograde direction. In this paper, we discuss how various axonal and actin trail parameters like axon diameter, trail nucleation rates, basal G-actin concentration, and trail length influence the transport rate. These predictions can help guide future experiments to verify this novel protein transport mechanism. We introduce a simplified, analytically solvable model of actin transport which relates these parameters to experimentally measurable quantities. We also discuss why a simple diffusion-based transport mechanism cannot explain bulk actin transport in the axon.
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Affiliation(s)
- Nilaj Chakrabarty
- Department of Physics and Astronomy, Neuroscience Program and Quantitative Biology Institute, Athens, OH 45701, United States of America
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36
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Gong Z, Fang C, You R, Shao X, Wei X, Chang RCC, Lin Y. Distinct relaxation timescales of neurites revealed by rate-dependent indentation, relaxation and micro-rheology tests. SOFT MATTER 2019; 15:166-174. [PMID: 30420982 DOI: 10.1039/c8sm01747f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Although the dynamic response of neurites is believed to play crucial roles in processes like axon outgrowth and formation of the neural network, the dynamic mechanical properties of such protrusions remain poorly understood. In this study, by using AFM (atomic force microscopy) indentation, we systematically examined the dynamic behavior of well-developed neurites on primary neurons under different loading modes (step loading, oscillating loading and ramp loading). Interestingly, the response was found to be strongly rate-dependent, with an apparent initial and long-term elastic modulus around 800 and 80 Pa, respectively. To better analyze the measurement data and extract information of key interest, the finite element simulation method (FEM) was also conducted where the neurite was treated as a viscoelastic solid consisting of multiple characteristic relaxation times. It was found that a minimum of three relaxation timescales, i.e. ∼0.01, 0.1 and 1 seconds, are needed to explain the observed relaxation curve as well as fit simulation results to the indentation and rheology data under different loading rates and driving frequencies. We further demonstrated that these three characteristic relaxation times likely originate from the thermal fluctuations of the microtubule, membrane relaxation and cytosol viscosity, respectively. By identifying key parameters describing the time-dependent behavior of neurites, as well as revealing possible physical mechanisms behind, this study could greatly help us understand how neural cells perform their biological duties over a wide spectrum of timescales.
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Affiliation(s)
- Ze Gong
- Department of Mechanical Engineering, University of Hong Kong, Hong Kong SAR, China.
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37
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Patel VB, Zhabyeyev P, Chen X, Wang F, Paul M, Fan D, McLean BA, Basu R, Zhang P, Shah S, Dawson JF, Pyle WG, Hazra M, Kassiri Z, Hazra S, Vanhaesebroeck B, McCulloch CA, Oudit GY. PI3Kα-regulated gelsolin activity is a critical determinant of cardiac cytoskeletal remodeling and heart disease. Nat Commun 2018; 9:5390. [PMID: 30568254 PMCID: PMC6300608 DOI: 10.1038/s41467-018-07812-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 11/28/2018] [Indexed: 12/21/2022] Open
Abstract
Biomechanical stress and cytoskeletal remodeling are key determinants of cellular homeostasis and tissue responses to mechanical stimuli and injury. Here we document the increased activity of gelsolin, an actin filament severing and capping protein, in failing human hearts. Deletion of gelsolin prevents biomechanical stress-induced adverse cytoskeletal remodeling and heart failure in mice. We show that phosphatidylinositol (3,4,5)-triphosphate (PIP3) lipid suppresses gelsolin actin-severing and capping activities. Accordingly, loss of PI3Kα, the key PIP3-producing enzyme in the heart, increases gelsolin-mediated actin-severing activities in the myocardium in vivo, resulting in dilated cardiomyopathy in response to pressure-overload. Mechanical stretching of adult PI3Kα-deficient cardiomyocytes disrupts the actin cytoskeleton, which is prevented by reconstituting cells with PIP3. The actin severing and capping activities of recombinant gelsolin are effectively suppressed by PIP3. Our data identify the role of gelsolin-driven cytoskeletal remodeling in heart failure in which PI3Kα/PIP3 act as negative regulators of gelsolin activity.
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Affiliation(s)
- Vaibhav B Patel
- Division of Cardiology, Department of Medicine, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
- Department of Physiology and Pharmacology and Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, HMRB-71, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
| | - Pavel Zhabyeyev
- Division of Cardiology, Department of Medicine, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
| | - Xueyi Chen
- Division of Cardiology, Department of Medicine, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
| | - Faqi Wang
- Division of Cardiology, Department of Medicine, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
| | - Manish Paul
- Department of Biotechnology, North Orissa University, Baripada, 757003, Odisha, India
| | - Dong Fan
- Mazankowski Alberta Heart Institute, University of Alberta, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
- Department of Physiology, University of Alberta, HMRC-407, 116 St 85 Ave, Edmonton, AB T6G 2S2, Canada
| | - Brent A McLean
- Mazankowski Alberta Heart Institute, University of Alberta, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
- Department of Physiology, University of Alberta, HMRC-407, 116 St 85 Ave, Edmonton, AB T6G 2S2, Canada
| | - Ratnadeep Basu
- Mazankowski Alberta Heart Institute, University of Alberta, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
- Department of Physiology, University of Alberta, HMRC-407, 116 St 85 Ave, Edmonton, AB T6G 2S2, Canada
| | - Pu Zhang
- Mazankowski Alberta Heart Institute, University of Alberta, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
- Department of Physiology, University of Alberta, HMRC-407, 116 St 85 Ave, Edmonton, AB T6G 2S2, Canada
| | - Saumya Shah
- Division of Cardiology, Department of Medicine, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
- Mazankowski Alberta Heart Institute, University of Alberta, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
| | - John F Dawson
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
- Centre of Cardiovascular Investigations, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - W Glen Pyle
- Centre of Cardiovascular Investigations, University of Guelph, Guelph, ON, N1G 2W1, Canada
- Department of Biomedical Sciences, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Mousumi Hazra
- Department of Botany and Microbiology, Gurukula Kangri University, Haridwar, 249404, Uttarakhand, India
| | - Zamaneh Kassiri
- Mazankowski Alberta Heart Institute, University of Alberta, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada
- Department of Physiology, University of Alberta, HMRC-407, 116 St 85 Ave, Edmonton, AB T6G 2S2, Canada
| | - Saugata Hazra
- Department of Biotechnology, Indian Institute of Technology, Roorkee, 247667, Uttarakhand, India
- Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, London, WC1E 6BT, England, UK
| | - Christopher A McCulloch
- Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, M5S 3E2, Canada
| | - Gavin Y Oudit
- Division of Cardiology, Department of Medicine, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada.
- Mazankowski Alberta Heart Institute, University of Alberta, 2C2, 8440-112 St, Edmonton, AB T6G 2B7, Canada.
- Department of Physiology, University of Alberta, HMRC-407, 116 St 85 Ave, Edmonton, AB T6G 2S2, Canada.
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38
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Miller KE, Suter DM. An Integrated Cytoskeletal Model of Neurite Outgrowth. Front Cell Neurosci 2018; 12:447. [PMID: 30534055 PMCID: PMC6275320 DOI: 10.3389/fncel.2018.00447] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/07/2018] [Indexed: 12/27/2022] Open
Abstract
Neurite outgrowth underlies the wiring of the nervous system during development and regeneration. Despite a significant body of research, the underlying cytoskeletal mechanics of growth and guidance are not fully understood, and the relative contributions of individual cytoskeletal processes to neurite growth are controversial. Here, we review the structural organization and biophysical properties of neurons to make a semi-quantitative comparison of the relative contributions of different processes to neurite growth. From this, we develop the idea that neurons are active fluids, which generate strong contractile forces in the growth cone and weaker contractile forces along the axon. As a result of subcellular gradients in forces and material properties, actin flows rapidly rearward in the growth cone periphery, and microtubules flow forward in bulk along the axon. With this framework, an integrated model of neurite outgrowth is proposed that hopefully will guide new approaches to stimulate neuronal growth.
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Affiliation(s)
- Kyle E Miller
- Department of Integrative Biology, Michigan State University, East Lansing, MI, United States
| | - Daniel M Suter
- Department of Biological Sciences, Purdue University, West Lafayette, IN, United States.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, United States.,Bindley Bioscience Center, Purdue University, West Lafayette, IN, United States.,Birck Nanotechnology Center, Purdue University, West Lafayette, IN, United States
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39
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Yamashiro S, Taniguchi D, Tanaka S, Kiuchi T, Vavylonis D, Watanabe N. Convection-Induced Biased Distribution of Actin Probes in Live Cells. Biophys J 2018; 116:142-150. [PMID: 30558885 DOI: 10.1016/j.bpj.2018.11.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 11/02/2018] [Accepted: 11/16/2018] [Indexed: 11/20/2022] Open
Abstract
Fluorescent markers that bind endogenous target proteins are frequently employed for quantitative live-cell imaging. To visualize the actin cytoskeleton in live cells, several actin-binding probes have been widely used. Among them, Lifeact is the most popular probe with ideal properties, including fast exchangeable binding kinetics. Because of its fast kinetics, Lifeact is generally believed to distribute evenly throughout cellular actin structures. In this study, however, we demonstrate misdistribution of Lifeact toward the rear of lamellipodia where actin filaments continuously move inward along the retrograde flow. Similarly, phalloidin showed biased misdistribution toward the rear of lamellipodia in live cells. We show evidence of convection-induced misdistribution of actin probes by both experimental data and physical models. Our findings warn about the potential error arising from the use of target-binding probes in quantitative live imaging.
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Affiliation(s)
- Sawako Yamashiro
- Laboratory of Single-Molecule Cell Biology, Kyoto University Graduate School of Medicine, Kyoto Japan; Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto Japan.
| | - Daisuke Taniguchi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto Japan
| | - Soichiro Tanaka
- Laboratory of Single-Molecule Cell Biology, Tohoku University Graduate School of Life Sciences, Sendai, Miyagi, Japan
| | - Tai Kiuchi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto Japan
| | | | - Naoki Watanabe
- Laboratory of Single-Molecule Cell Biology, Kyoto University Graduate School of Medicine, Kyoto Japan; Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto Japan.
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40
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Parreno J, Fowler VM. Multifunctional roles of tropomodulin-3 in regulating actin dynamics. Biophys Rev 2018; 10:1605-1615. [PMID: 30430457 DOI: 10.1007/s12551-018-0481-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/08/2018] [Indexed: 12/12/2022] Open
Abstract
Tropomodulins (Tmods) are proteins that cap the slow-growing (pointed) ends of actin filaments (F-actin). The basis for our current understanding of Tmod function comes from studies in cells with relatively stable and highly organized F-actin networks, leading to the view that Tmod capping functions principally to preserve F-actin stability. However, not only is Tmod capping dynamic, but it also can play major roles in regulating diverse cellular processes involving F-actin remodeling. Here, we highlight the multifunctional roles of Tmod with a focus on Tmod3. Like other Tmods, Tmod3 binds tropomyosin (Tpm) and actin, capping pure F-actin at submicromolar and Tpm-coated F-actin at nanomolar concentrations. Unlike other Tmods, Tmod3 can also bind actin monomers and its ability to bind actin is inhibited by phosphorylation of Tmod3 by Akt2. Tmod3 is ubiquitously expressed and is present in a diverse array of cytoskeletal structures, including contractile structures such as sarcomere-like units of actomyosin stress fibers and in the F-actin network encompassing adherens junctions. Tmod3 participates in F-actin network remodeling in lamellipodia during cell migration and in the assembly of specialized F-actin networks during exocytosis. Furthermore, Tmod3 is required for development, regulating F-actin mesh formation during meiosis I of mouse oocytes, erythroblast enucleation in definitive erythropoiesis, and megakaryocyte morphogenesis in the mouse fetal liver. Thus, Tmod3 plays vital roles in dynamic and stable F-actin networks in cell physiology and development, with further research required to delineate the mechanistic details of Tmod3 regulation in the aforementioned processes, or in other yet to be discovered processes.
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Affiliation(s)
- Justin Parreno
- Department of Molecular Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Velia M Fowler
- Department of Molecular Medicine, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA, 92037, USA.
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41
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Tropomodulin Isoform-Specific Regulation of Dendrite Development and Synapse Formation. J Neurosci 2018; 38:10271-10285. [PMID: 30301754 DOI: 10.1523/jneurosci.3325-17.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 09/25/2018] [Accepted: 10/02/2018] [Indexed: 11/21/2022] Open
Abstract
Neurons of the CNS elaborate highly branched dendritic arbors that host numerous dendritic spines, which serve as the postsynaptic platform for most excitatory synapses. The actin cytoskeleton plays an important role in dendrite development and spine formation, but the underlying mechanisms remain incompletely understood. Tropomodulins (Tmods) are a family of actin-binding proteins that cap the slow-growing (pointed) end of actin filaments, thereby regulating the stability, length, and architecture of complex actin networks in diverse cell types. Three members of the Tmod family, Tmod1, Tmod2, and Tmod3 are expressed in the vertebrate CNS, but their function in neuronal development is largely unknown. In this study, we present evidence that Tmod1 and Tmod2 exhibit distinct roles in regulating spine development and dendritic arborization, respectively. Using rat hippocampal tissues from both sexes, we find that Tmod1 and Tmod2 are expressed with distinct developmental profiles: Tmod2 is expressed early during hippocampal development, whereas Tmod1 expression coincides with synaptogenesis. We then show that knockdown of Tmod2, but not Tmod1, severely impairs dendritic branching. Both Tmod1 and Tmod2 are localized to a distinct subspine region where they regulate local F-actin stability. However, the knockdown of Tmod1, but not Tmod2, disrupts spine morphogenesis and impairs synapse formation. Collectively, these findings demonstrate that regulation of the actin cytoskeleton by different members of the Tmod family plays an important role in distinct aspects of dendrite and spine development.SIGNIFICANCE STATEMENT The Tropomodulin family of molecules is best known for controlling the length and stability of actin myofilaments in skeletal muscles. While several Tropomodulin members are expressed in the brain, fundamental knowledge about their role in neuronal function is limited. In this study, we show the unique expression profile and subcellular distribution of Tmod1 and Tmod2 in hippocampal neurons. While both Tmod1 and Tmod2 regulate F-actin stability, we find that they exhibit isoform-specific roles in dendrite development and synapse formation: Tmod2 regulates dendritic arborization, whereas Tmod1 is required for spine development and synapse formation. These findings provide novel insight into the actin regulatory mechanisms underlying neuronal development, thereby shedding light on potential pathways disrupted in a number of neurological disorders.
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42
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Assembling actin filaments for protrusion. Curr Opin Cell Biol 2018; 56:53-63. [PMID: 30278304 DOI: 10.1016/j.ceb.2018.09.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/10/2018] [Accepted: 09/17/2018] [Indexed: 12/31/2022]
Abstract
Cell migration entails a plethora of activities combining the productive exertion of protrusive and contractile forces to allow cells to push and squeeze themselves through cell clumps, interstitial tissues or tissue borders. All these activities require the generation and turnover of actin filaments that arrange into specific, subcellular structures. The most prominent structures mediating the protrusion at the leading edges of cells include lamellipodia and filopodia as well as plasma membrane blebs. Moreover, in cells migrating on planar substratum, mechanical support is being provided by an additional, more proximally located structure termed the lamella. Here, we systematically dissect the literature concerning the mechanisms driving actin filament nucleation and elongation in the best-studied protrusive structure, the lamellipodium. Recent work has shed light on open questions in lamellipodium protrusion, including the relative contributions of nucleation versus elongation to the assembly of both individual filaments and the lamellipodial network as a whole. However, much remains to be learned concerning the specificity and relevance of individual factors, their cooperation and their site-specific functions relative to the importance of global actin monomer and filament homeostasis.
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43
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Zepeta-Flores N, Valverde M, Lopez-Saavedra A, Rojas E. Glutathione depletion triggers actin cytoskeleton changes via actin-binding proteins. Genet Mol Biol 2018; 41:475-487. [PMID: 29870570 PMCID: PMC6082235 DOI: 10.1590/1678-4685-gmb-2017-0158] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 11/18/2017] [Indexed: 11/30/2022] Open
Abstract
The importance of glutathione (GSH) in alternative cellular roles to the
canonically proposed, were analyzed in a model unable to synthesize GSH. Gene
expression analysis shows that the regulation of the actin cytoskeleton pathway
is strongly impacted by the absence of GSH. To test this hypothesis, we evaluate
the effect of GSH depletion via buthionine sulfoximine (5 and 12.5 mM) in human
neuroblastoma MSN cells. In the present study, 70% of GSH reduction did not
induce reactive oxygen species, lipoperoxidation, or cytotoxicity, which enabled
us to evaluate the effect of glutathione in the absence of oxidative stress. The
cells with decreasing GSH levels acquired morphology changes that depended on
the actin cytoskeleton and not on tubulin. We evaluated the expression of three
actin-binding proteins: thymosin β4, profilin and gelsolin, showing a reduced
expression, both at gene and protein levels at 24 hours of treatment; however,
this suppression disappears after 48 hours of treatment. These changes were
sufficient to trigger the co-localization of the three proteins towards
cytoplasmic projections. Our data confirm that a decrease in GSH in the absence
of oxidative stress can transiently inhibit the actin binding proteins and that
this stimulus is sufficient to induce changes in cellular morphology via the
actin cytoskeleton.
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Affiliation(s)
- Nahum Zepeta-Flores
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F., Mexico
| | - Mahara Valverde
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F., Mexico
| | - Alejandro Lopez-Saavedra
- Unidad Biomédica de Investigación en Cáncer, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Instituto Nacional de Cancerología, México. D.F., Mexico
| | - Emilio Rojas
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México D.F., Mexico
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44
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Lopata A, Hughes R, Tiede C, Heissler SM, Sellers JR, Knight PJ, Tomlinson D, Peckham M. Affimer proteins for F-actin: novel affinity reagents that label F-actin in live and fixed cells. Sci Rep 2018; 8:6572. [PMID: 29700342 PMCID: PMC5920084 DOI: 10.1038/s41598-018-24953-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 04/10/2018] [Indexed: 01/21/2023] Open
Abstract
Imaging the actin cytoskeleton in cells uses a wide range of approaches. Typically, a fluorescent derivative of the small cyclic peptide phalloidin is used to image F-actin in fixed cells. Lifeact and F-tractin are popular for imaging the cytoskeleton in live cells. Here we characterised novel affinity reagents called Affimers that specifically bind to F-actin in vitro to determine if they are suitable alternatives as eGFP-fusion proteins, to label actin in live cells, or for labeling F-actin in fixed cells. In vitro experiments showed that 3 out of the 4 Affimers (Affimers 6, 14 and 24) tested bind tightly to purified F-actin, and appear to have overlapping binding sites. As eGFP-fusion proteins, the same 3 Affimers label F-actin in live cells. FRAP experiments suggest that eGFP-Affimer 6 behaves most similarly to F-tractin and Lifeact. However, it does not colocalise with mCherry-actin in dynamic ruffles, and may preferentially bind stable actin filaments. All 4 Affimers label F-actin in methanol fixed cells, while only Affimer 14 labels F-actin after paraformaldehyde fixation. eGFP-Affimer 6 has potential for use in selectively imaging the stable actin cytoskeleton in live cells, while all 4 Affimers are strong alternatives to phalloidin for labelling F-actin in fixed cells.
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Affiliation(s)
- Anna Lopata
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK.,Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, Bethesda, MD, 20892, USA
| | - Ruth Hughes
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Christian Tiede
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Sarah M Heissler
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, Bethesda, MD, 20892, USA
| | - James R Sellers
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, Bethesda, MD, 20892, USA
| | - Peter J Knight
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Darren Tomlinson
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Michelle Peckham
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK.
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45
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Fu Y, Yu W, Cai H, Lu A. Forecast of actin-binding proteins as the oncotarget in osteosarcoma - a review of mechanism, diagnosis and therapy. Onco Targets Ther 2018; 11:1553-1561. [PMID: 29593421 PMCID: PMC5865567 DOI: 10.2147/ott.s159894] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Osteosarcoma (OS) is the most common bone malignant tumor with a high rate of lung metastasis and principally emerges in children and adolescents. Although neoadjuvant chemotherapy is widely used around the world, a high rate of chemoresistance occurs and frequently generates a poor prognosis. Therefore, finding a new appropriate prognostic marker for OS is a valuable research direction, which will give patients a better chance to receive proper therapy. Actin-binding proteins (ABPs) are a group of proteins that interact with actin cytoskeleton and play a crucial role in the regulation of the cell motility and morphology in eukaryotes. Meanwhile, ABPs also act as a bridge between the cytomembrane and nucleus, which transmit the outside-in and inside-out signals in cytoplasm. Furthermore, ABPs alter the dynamic structure of actin and regulate the invasion and metastasis of cancer. Hence, ABPs have a wide application in predicting the prognosis, and may be new targets, in tumor therapy. This review focuses on a series of ABPs and discusses their modulatory functions. It provides a new insight into the classification of ABPs’ functions in the process of invasion and metastasis in OS and illuminates the potential ability in predicting the prognosis of OS patients.
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Affiliation(s)
- Yucheng Fu
- Department of Surgical Intensive Care Unit, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, People's Republic of China
| | - Wei Yu
- Department of Orthopedics, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, People's Republic of China
| | - Hongliu Cai
- Department of Surgical Intensive Care Unit, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, People's Republic of China
| | - Anwei Lu
- Department of Surgical Intensive Care Unit, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, People's Republic of China
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46
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Skruber K, Read TA, Vitriol EA. Reconsidering an active role for G-actin in cytoskeletal regulation. J Cell Sci 2018; 131:131/1/jcs203760. [PMID: 29321224 DOI: 10.1242/jcs.203760] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Globular (G)-actin, the actin monomer, assembles into polarized filaments that form networks that can provide structural support, generate force and organize the cell. Many of these structures are highly dynamic and to maintain them, the cell relies on a large reserve of monomers. Classically, the G-actin pool has been thought of as homogenous. However, recent work has shown that actin monomers can exist in distinct groups that can be targeted to specific networks, where they drive and modify filament assembly in ways that can have profound effects on cellular behavior. This Review focuses on the potential factors that could create functionally distinct pools of actin monomers in the cell, including differences between the actin isoforms and the regulation of G-actin by monomer binding proteins, such as profilin and thymosin β4. Owing to difficulties in studying and visualizing G-actin, our knowledge over the precise role that specific actin monomer pools play in regulating cellular actin dynamics remains incomplete. Here, we discuss some of these unanswered questions and also provide a summary of the methodologies currently available for the imaging of G-actin.
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Affiliation(s)
- Kristen Skruber
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
| | - Tracy-Ann Read
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
| | - Eric A Vitriol
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
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Bartle EI, Rao TC, Urner TM, Mattheyses AL. Bridging the gap: Super-resolution microscopy of epithelial cell junctions. Tissue Barriers 2018; 6:e1404189. [PMID: 29420122 PMCID: PMC5823550 DOI: 10.1080/21688370.2017.1404189] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 10/26/2017] [Accepted: 10/30/2017] [Indexed: 02/02/2023] Open
Abstract
Cell junctions are critical for cell adhesion and communication in epithelial tissues. It is evident that the cellular distribution, size, and architecture of cell junctions play a vital role in regulating function. These details of junction architecture have been challenging to elucidate in part due to the complexity and size of cell junctions. A major challenge in understanding these features is attaining high resolution spatial information with molecular specificity. Fluorescence microscopy allows localization of specific proteins to junctions, but with a resolution on the same scale as junction size, rendering internal protein organization unobtainable. Super-resolution microscopy provides a bridge between fluorescence microscopy and nanoscale approaches, utilizing fluorescent tags to reveal protein organization below the resolution limit. Here we provide a brief introduction to super-resolution microscopy and discuss novel findings into the organization, structure and function of epithelial cell junctions.
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Affiliation(s)
- Emily I. Bartle
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tejeshwar C. Rao
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tara M. Urner
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alexa L. Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
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Chang M, Li Z, Huang S. Monomeric G-actin is uniformly distributed in pollen tubes and is rapidly redistributed via cytoplasmic streaming during pollen tube growth. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 92:509-519. [PMID: 28845534 DOI: 10.1111/tpj.13668] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 08/11/2017] [Accepted: 08/18/2017] [Indexed: 05/25/2023]
Abstract
Dynamic assembly and disassembly of the actin cytoskeleton has been implicated in the regulation of pollen germination and subsequent tube growth. It is widely accepted that actin filaments are arrayed into distinct structures within different regions of the pollen tube. Maintenance of the equilibrium between monomeric globular actin (G-actin) and filamentous actin (F-actin) is crucial for actin assembly and array construction, and the local concentration of G-actin thus directly impacts actin assembly. The localization and dynamics of G-actin in the pollen tube, however, remain to be determined conclusively. To address this question, we created a series of fusion proteins between green fluorescent protein (GFP) and the Arabidopsis reproductive actin ACT11. Expression of a fusion protein with GFP inserted after methionine at position 49 within the DNase I-binding loop of ACT11 (GFPMet49 -ACT11) rescued the phenotypes in act11 mutants. Consistent with the notion that the majority of actin is in its monomeric form, GFPMet49 -ACT11 and GFP fusion proteins of four other reproductive actins generated with the same strategy do not obviously label filamentous structures. In further support of the functionality of these fusion proteins, we found that they can be incorporated into filamentous structures in jasplakinolide (Jasp)-treated pollen tubes. Careful observations showed that G-actin is distributed uniformly in the pollen tube and is rapidly redistributed via cytoplasmic streaming during pollen tube growth. Our study suggests that G-actin is readily available in the cytoplasm to support continuous actin polymerization during rapid pollen tube growth.
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Affiliation(s)
- Ming Chang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Zhankun Li
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
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Raz-Ben Aroush D, Ofer N, Abu-Shah E, Allard J, Krichevsky O, Mogilner A, Keren K. Actin Turnover in Lamellipodial Fragments. Curr Biol 2017; 27:2963-2973.e14. [PMID: 28966086 DOI: 10.1016/j.cub.2017.08.066] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 07/21/2017] [Accepted: 08/29/2017] [Indexed: 10/18/2022]
Abstract
Actin turnover is the central driving force underlying lamellipodial motility. The molecular components involved are largely known, and their properties have been studied extensively in vitro. However, a comprehensive picture of actin turnover in vivo is still missing. We focus on fragments from fish epithelial keratocytes, which are essentially stand-alone motile lamellipodia. The geometric simplicity of the fragments and the absence of additional actin structures allow us to characterize the spatiotemporal lamellipodial actin organization with unprecedented detail. We use fluorescence recovery after photobleaching, fluorescence correlation spectroscopy, and extraction experiments to show that about two-thirds of the lamellipodial actin diffuses in the cytoplasm with nearly uniform density, whereas the rest forms the treadmilling polymer network. Roughly a quarter of the diffusible actin pool is in filamentous form as diffusing oligomers, indicating that severing and debranching are important steps in the disassembly process generating oligomers as intermediates. The remaining diffusible actin concentration is orders of magnitude higher than the in vitro actin monomer concentration required to support the observed polymerization rates, implying that the majority of monomers are transiently kept in a non-polymerizable "reserve" pool. The actin network disassembles and reassembles throughout the lamellipodium within seconds, so the lamellipodial network turnover is local. The diffusible actin transport, on the other hand, is global: actin subunits typically diffuse across the entire lamellipodium before reassembling into the network. This combination of local network turnover and global transport of dissociated subunits through the cytoplasm makes actin transport robust yet rapidly adaptable and amenable to regulation.
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Affiliation(s)
- Dikla Raz-Ben Aroush
- Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Noa Ofer
- Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel; Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Enas Abu-Shah
- Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel; Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Jun Allard
- Department of Mathematics, Center for Complex Biological Systems and Department of Physics and Astronomy, University of California at Irvine, Irvine, CA 92697, USA
| | - Oleg Krichevsky
- Physics Department and Ilse Kats Center for Nanoscience, Ben-Gurion University, Beer-Sheva 84105, Israel
| | - Alex Mogilner
- Courant Institute of Mathematical Sciences and Department of Biology, New York University, New York, NY 10012, USA.
| | - Kinneret Keren
- Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel; Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel; Network Biology Research Laboratories, Technion-Israel Institute of Technology, Haifa 32000, Israel.
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Boujemaa-Paterski R, Suarez C, Klar T, Zhu J, Guérin C, Mogilner A, Théry M, Blanchoin L. Network heterogeneity regulates steering in actin-based motility. Nat Commun 2017; 8:655. [PMID: 28935896 PMCID: PMC5608943 DOI: 10.1038/s41467-017-00455-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 06/29/2017] [Indexed: 11/10/2022] Open
Abstract
The growth of branched actin networks powers cell-edge protrusions and motility. A heterogeneous density of actin, which yields to a tunable cellular response, characterizes these dynamic structures. We study how actin organization controls both the rate and the steering during lamellipodium growth. We use a high-resolution surface structuration assay combined with mathematical modeling to describe the growth of a reconstituted lamellipodium. We demonstrate that local monomer depletion at the site of assembly negatively impacts the network growth rate. At the same time, network architecture tunes the protrusion efficiency, and regulates the rate of growth. One consequence of this interdependence between monomer depletion and network architecture effects is the ability of heterogeneous network to impose steering during motility. Therefore, we have established that the general principle, by which the cell can modulate the rate and the direction of a protrusion, is by varying both density and architecture of its actin network. Protrusive cellular structures contain a heterogeneous density of actin, but whether this influences motility is not known. Using an in vitro system and modelling, here the authors show that local actin monomer depletion and network architecture can tune the rate of network growth to impose steering during motility.
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Affiliation(s)
- Rajaa Boujemaa-Paterski
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, 38054, Grenoble, France
| | - Cristian Suarez
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, 38054, Grenoble, France
| | - Tobias Klar
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, 38054, Grenoble, France
| | - Jie Zhu
- Courant Institute of Mathematical Sciences and Department of Biology, New York University, New York, NY, 10012, USA
| | - Christophe Guérin
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, 38054, Grenoble, France
| | - Alex Mogilner
- Courant Institute of Mathematical Sciences and Department of Biology, New York University, New York, NY, 10012, USA.
| | - Manuel Théry
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, 38054, Grenoble, France. .,CytomorphoLab, Hôpital Saint Louis, Institut Universitaire d'Hematologie, UMRS1160, INSERM/AP-HP/Université Paris Diderot, 75010, Paris, France.
| | - Laurent Blanchoin
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, 38054, Grenoble, France. .,CytomorphoLab, Hôpital Saint Louis, Institut Universitaire d'Hematologie, UMRS1160, INSERM/AP-HP/Université Paris Diderot, 75010, Paris, France.
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