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Schaks M, Döring H, Kage F, Steffen A, Klünemann T, Blankenfeldt W, Stradal T, Rottner K. RhoG and Cdc42 can contribute to Rac-dependent lamellipodia formation through WAVE regulatory complex-binding. Small GTPases 2019; 12:122-132. [PMID: 31451035 PMCID: PMC7849749 DOI: 10.1080/21541248.2019.1657755] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Cell migration frequently involves the formation of lamellipodial protrusions, the initiation of which requires Rac GTPases signalling to heteropentameric WAVE regulatory complex (WRC). While Rac-related RhoG and Cdc42 can potently stimulate lamellipodium formation, so far presumed to occur by upstream signalling to Rac activation, we show here that the latter can be bypassed by RhoG and Cdc42 given that WRC has been artificially activated. This evidence arises from generation of B16-F1 cells simultaneously lacking both Rac GTPases and WRC, followed by reconstitution of lamellipodia formation with specific Rho-GTPase and differentially active WRC variant combinations. We conclude that formation of canonical lamellipodia requires WRC activation through Rac, but can possibly be tuned, in addition, by WRC interactions with RhoG and Cdc42.
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Affiliation(s)
- Matthias Schaks
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig , Braunschweig, Germany.,Cell Biology, Helmholtz Centre for Infection Research , Braunschweig, Germany
| | - Hermann Döring
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig , Braunschweig, Germany.,Cell Biology, Helmholtz Centre for Infection Research , Braunschweig, Germany
| | - Frieda Kage
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig , Braunschweig, Germany.,Cell Biology, Helmholtz Centre for Infection Research , Braunschweig, Germany
| | - Anika Steffen
- Cell Biology, Helmholtz Centre for Infection Research , Braunschweig, Germany
| | - Thomas Klünemann
- Structure and Function of Proteins, Helmholtz Centre for Infection Research , Braunschweig, Germany
| | - Wulf Blankenfeldt
- Structure and Function of Proteins, Helmholtz Centre for Infection Research , Braunschweig, Germany
| | - Theresia Stradal
- Cell Biology, Helmholtz Centre for Infection Research , Braunschweig, Germany
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig , Braunschweig, Germany.,Cell Biology, Helmholtz Centre for Infection Research , Braunschweig, Germany
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52
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The Architecture of Traveling Actin Waves Revealed by Cryo-Electron Tomography. Structure 2019; 27:1211-1223.e5. [PMID: 31230946 DOI: 10.1016/j.str.2019.05.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/12/2019] [Accepted: 05/17/2019] [Indexed: 02/06/2023]
Abstract
Actin waves are dynamic supramolecular structures involved in cell migration, cytokinesis, adhesion, and neurogenesis. Although wave-like propagation of actin networks is a widespread phenomenon, the actin architecture underlying wave propagation remained unknown. In situ cryo-electron tomography of Dictyostelium cells unveils the wave architecture and provides evidence for wave progression by de novo actin nucleation. Subtomogram averaging reveals the structure of Arp2/3 complex-mediated branch junctions in their native state, and enables quantitative analysis of the 3D organization of branching within the waves. We find an excess of branches directed toward the substrate-attached membrane, and tent-like structures at sites of branch clustering. Fluorescence imaging shows that Arp2/3 clusters follow accumulation of the elongation factor VASP. We propose that filament growth toward the membrane lifts up the actin network as the wave propagates, until depolymerization of oblique filaments at the back causes the collapse of horizontal filaments into a compact layer.
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53
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Umeki N, Shibata K, Noguchi TQP, Hirose K, Sako Y, Uyeda TQP. K336I mutant actin alters the structure of neighbouring protomers in filaments and reduces affinity for actin-binding proteins. Sci Rep 2019; 9:5353. [PMID: 30926871 PMCID: PMC6441083 DOI: 10.1038/s41598-019-41795-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 03/18/2019] [Indexed: 12/16/2022] Open
Abstract
Mutation of the Lys-336 residue of actin to Ile (K336I) or Asp (K336E) causes congenital myopathy. To understand the effect of this mutation on the function of actin filaments and gain insight into the mechanism of disease onset, we prepared and biochemically characterised K336I mutant actin from Dictyostelium discoideum. Subtilisin cleavage assays revealed that the structure of the DNase-I binding loop (D-loop) of monomeric K336I actin, which would face the adjacent actin-protomer in filaments, differed from that of wild type (WT) actin. Although K336I actin underwent normal salt-dependent reversible polymerisation and formed apparently normal filaments, interactions of K336I filaments with alpha-actinin, myosin II, and cofilin were disrupted. Furthermore, co-filaments of K336I and WT actins also exhibited abnormal interactions with cofilin, implying that K336I actin altered the structure of the neighbouring WT actin protomers such that interaction between cofilin and the WT actin protomers was prevented. We speculate that disruption of the interactions between co-filaments and actin-binding proteins is the primary reason why the K336I mutation induces muscle disease in a dominant fashion.
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Affiliation(s)
- Nobuhisa Umeki
- Cellular Informatics Lab., RIKEN, Wako, Saitama, 351-0198, Japan. .,Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8562, Japan.
| | - Keitaro Shibata
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8562, Japan.,Advanced ICT Research Institute, National Institute of Information and Communications Technology (NICT), Kobe, Hyogo, 651-2492, Japan
| | - Taro Q P Noguchi
- National Institute of Technology, Miyakonojo College, Miyakonojo, Miyazaki, 885-8567, Japan
| | - Keiko Hirose
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8562, Japan
| | - Yasushi Sako
- Cellular Informatics Lab., RIKEN, Wako, Saitama, 351-0198, Japan
| | - Taro Q P Uyeda
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8562, Japan.,Department of Physics, Waseda University, Shinjuku, Tokyo, 169-8555, Japan
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54
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Manhart A, Icheva TA, Guerin C, Klar T, Boujemaa-Paterski R, Thery M, Blanchoin L, Mogilner A. Quantitative regulation of the dynamic steady state of actin networks. eLife 2019; 8:42413. [PMID: 30869077 PMCID: PMC6417862 DOI: 10.7554/elife.42413] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 02/26/2019] [Indexed: 12/30/2022] Open
Abstract
Principles of regulation of actin network dimensions are fundamentally important for cell functions, yet remain unclear. Using both in vitro and in silico approaches, we studied the effect of key parameters, such as actin density, ADF/Cofilin concentration and network width on the network length. In the presence of ADF/Cofilin, networks reached equilibrium and became treadmilling. At the trailing edge, the network disintegrated into large fragments. A mathematical model predicts the network length as a function of width, actin and ADF/Cofilin concentrations. Local depletion of ADF/Cofilin by binding to actin is significant, leading to wider networks growing longer. A single rate of breaking network nodes, proportional to ADF/Cofilin density and inversely proportional to the square of the actin density, can account for the disassembly dynamics. Selective disassembly of heterogeneous networks by ADF/Cofilin controls steering during motility. Our results establish general principles on how the dynamic steady state of actin network emerges from biochemical and structural feedbacks.
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Affiliation(s)
- Angelika Manhart
- Courant Institute of Mathematical Sciences, New York University, New York, United States.,Department of Biology, New York University, New York, United States
| | - Téa Aleksandra Icheva
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France
| | - Christophe Guerin
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France
| | - Tobbias Klar
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France
| | - Rajaa Boujemaa-Paterski
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France
| | - Manuel Thery
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France.,CytomorphoLab, Hôpital Saint Louis, Institut Universitaire d'Hematologie, UMRS1160, INSERM/AP-HP/Université Paris Diderot, Paris, France
| | - Laurent Blanchoin
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France.,CytomorphoLab, Hôpital Saint Louis, Institut Universitaire d'Hematologie, UMRS1160, INSERM/AP-HP/Université Paris Diderot, Paris, France
| | - Alex Mogilner
- Courant Institute of Mathematical Sciences, New York University, New York, United States.,Department of Biology, New York University, New York, United States
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55
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Holz D, Vavylonis D. Building a dendritic actin filament network branch by branch: models of filament orientation pattern and force generation in lamellipodia. Biophys Rev 2018; 10:1577-1585. [PMID: 30421277 DOI: 10.1007/s12551-018-0475-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 10/21/2018] [Indexed: 01/02/2023] Open
Abstract
We review mathematical and computational models of the structure, dynamics, and force generation properties of dendritic actin networks. These models have been motivated by the dendritic nucleation model, which provided a mechanistic picture of how the actin cytoskeleton system powers cell motility. We describe how they aimed to explain the self-organization of the branched network into a bimodal distribution of filament orientations peaked at 35° and - 35° with respect to the direction of membrane protrusion, as well as other patterns. Concave and convex force-velocity relationships were derived, depending on network organization, filament, and membrane elasticity and accounting for actin polymerization at the barbed end as a Brownian ratchet. This review also describes models that considered the kinetics and transport of actin and diffuse regulators and mechanical coupling to a substrate, together with explicit modeling of dendritic networks.
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Affiliation(s)
- Danielle Holz
- Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, PA, 18105, USA
| | - Dimitrios Vavylonis
- Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, PA, 18105, USA.
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