1
|
Ueda Y, Matsunaga D, Deguchi S. Asymmetric response emerges between creation and disintegration of force-bearing subcellular structures as revealed by percolation analysis. Integr Biol (Camb) 2024; 16:zyae012. [PMID: 38900169 DOI: 10.1093/intbio/zyae012] [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: 03/23/2024] [Revised: 05/23/2024] [Indexed: 06/21/2024]
Abstract
Cells dynamically remodel their internal structures by modulating the arrangement of actin filaments (AFs). In this process, individual AFs exhibit stochastic behavior without knowing the macroscopic higher-order structures they are meant to create or disintegrate, but the mechanism allowing for such stochastic process-driven remodeling of subcellular structures remains incompletely understood. Here we employ percolation theory to explore how AFs interacting only with neighboring ones without recognizing the overall configuration can nonetheless create a substantial structure referred to as stress fibers (SFs) at particular locations. We determined the interaction probabilities of AFs undergoing cellular tensional homeostasis, a fundamental property maintaining intracellular tension. We showed that the duration required for the creation of SFs is shortened by the increased amount of preexisting actin meshwork, while the disintegration occurs independently of the presence of actin meshwork, suggesting that the coexistence of tension-bearing and non-bearing elements allows cells to promptly transition to new states in accordance with transient environmental changes. The origin of this asymmetry between creation and disintegration, consistently observed in actual cells, is elucidated through a minimal model analysis by examining the intrinsic nature of mechano-signal transmission. Specifically, unlike the symmetric case involving biochemical communication, physical communication to sense environmental changes is facilitated via AFs under tension, while other free AFs dissociated from tension-bearing structures exhibit stochastic behavior. Thus, both the numerical and minimal models demonstrate the essence of intracellular percolation, in which macroscopic asymmetry observed at the cellular level emerges not from microscopic asymmetry in the interaction probabilities of individual molecules, but rather only as a consequence of the manner of the mechano-signal transmission. These results provide novel insights into the role of the mutual interplay between distinct subcellular structures with and without tension-bearing capability. Insight: Cells continuously remodel their internal elements or structural proteins in response to environmental changes. Despite the stochastic behavior of individual structural proteins, which lack awareness of the larger subcellular structures they are meant to create or disintegrate, this self-assembly process somehow occurs to enable adaptation to the environment. Here we demonstrated through percolation simulations and minimal model analyses that there is an asymmetry in the response between the creation and disintegration of subcellular structures, which can aid environmental adaptation. This asymmetry inherently arises from the nature of mechano-signal transmission through structural proteins, namely tension-mediated information exchange within cells, despite the stochastic behavior of individual proteins lacking asymmetric characters in themselves.
Collapse
Affiliation(s)
- Yuika Ueda
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University
| | - Daiki Matsunaga
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University
| | - Shinji Deguchi
- Division of Bioengineering, Graduate School of Engineering Science, Osaka University
| |
Collapse
|
2
|
Alimov N, Hoeprich GJ, Padrick SB, Goode BL. Cyclase-associated protein interacts with actin filament barbed ends to promote depolymerization and formin displacement. J Biol Chem 2023; 299:105367. [PMID: 37863260 PMCID: PMC10692737 DOI: 10.1016/j.jbc.2023.105367] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 10/04/2023] [Accepted: 10/12/2023] [Indexed: 10/22/2023] Open
Abstract
Cyclase-associated protein (CAP) has emerged as a central player in cellular actin turnover, but its molecular mechanisms of action are not yet fully understood. Recent studies revealed that the N terminus of CAP interacts with the pointed ends of actin filaments to accelerate depolymerization in conjunction with cofilin. Here, we use in vitro microfluidics-assisted TIRF microscopy to show that the C terminus of CAP promotes depolymerization at the opposite (barbed) ends of actin filaments. In the absence of actin monomers, full-length mouse CAP1 and C-terminal halves of CAP1 (C-CAP1) and CAP2 (C-CAP2) accelerate barbed end depolymerization. Using mutagenesis and structural modeling, we show that these activities are mediated by the WH2 and CARP domains of CAP. In addition, we observe that CAP collaborates with profilin to accelerate barbed end depolymerization and that these effects depend on their direct interaction, providing the first known example of CAP-profilin collaborative effects in regulating actin. In the presence of actin monomers, CAP1 attenuates barbed end growth and promotes formin dissociation. Overall, these findings demonstrate that CAP uses distinct domains and mechanisms to interact with opposite ends of actin filaments and drive turnover. Further, they contribute to the emerging view of actin barbed ends as sites of dynamic molecular regulation, where numerous proteins compete and cooperate with each other to tune polymer dynamics, similar to the rich complexity seen at microtubule ends.
Collapse
Affiliation(s)
- Nikita Alimov
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Gregory J Hoeprich
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Shae B Padrick
- Department of Biochemistry and Molecular Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA.
| |
Collapse
|
3
|
Asante-Asamani E, Dalton M, Brazill D, Strychalski W. Modeling the dynamics of actin and myosin during bleb stabilization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.26.564082. [PMID: 37961169 PMCID: PMC10634845 DOI: 10.1101/2023.10.26.564082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The actin cortex is very dynamic during migration of eukaryotes. In cells that use blebs as leading-edge protrusions, the cortex reforms beneath the cell membrane (bleb cortex) and completely disassembles at the site of bleb initiation. Remnants of the actin cortex at the site of bleb nucleation are referred to as the actin scar. We refer to the combined process of cortex reformation along with the degradation of the actin scar during bleb-based cell migration as bleb stabilization. The molecular factors that regulate the dynamic reorganization of the cortex are not fully understood. Myosin motor protein activity has been shown to be necessary for blebbing, with its major role associated with pressure generation to drive bleb expansion. Here, we examine the role of myosin in regulating cortex dynamics during bleb stabilization. Analysis of microscopy data from protein localization experiments in Dictyostelium discoideum cells reveals a rapid formation of the bleb's cortex with a delay in myosin accumulation. In the degrading actin scar, myosin is observed to accumulate before active degradation of the cortex begins. Through a combination of mathematical modeling and data fitting, we identify that myosin helps regulate the equilibrium concentration of actin in the bleb cortex during its reformation by increasing its dissasembly rate. Our modeling and analysis also suggests that cortex degradation is driven primarily by an exponential decrease in actin assembly rate rather than increased myosin activity. We attribute the decrease in actin assembly to the separation of the cell membrane from the cortex after bleb nucleation.
Collapse
Affiliation(s)
| | - Mackenzie Dalton
- Department of Mathematics, Clarkson University, Clarkson, Potsdam, NY 13699
| | | | - Wanda Strychalski
- Department of Mathematics, Applied Mathematics, and Statistics, Case Western Reserve University, Cleveland, OH 44106
| |
Collapse
|
4
|
Extraction of accurate cytoskeletal actin velocity distributions from noisy measurements. Nat Commun 2022; 13:4749. [PMID: 35963858 PMCID: PMC9376101 DOI: 10.1038/s41467-022-31583-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 06/23/2022] [Indexed: 11/09/2022] Open
Abstract
Dynamic remodeling of the actin cytoskeleton is essential for many cellular processes. Tracking the movement of individual actin filaments can in principle shed light on how this complex behavior arises at the molecular level. However, the information that can be extracted from these measurements is often limited by low signal-to-noise ratios. We developed a Bayesian statistical approach to estimate true, underlying velocity distributions from the tracks of individual actin-associated fluorophores with quantified localization uncertainties. We found that the motion of filamentous (F)-actin in fibroblasts and endothelial cells was better described by a statistical jump process than by models in which filaments undergo continuous, diffusive movement. In particular, a model with exponentially distributed jump length- and time-scales recapitulated actin filament velocity distributions measured for the cell cortex, integrin-based adhesions, and stress fibers, suggesting that a common physical model can potentially describe actin filament dynamics in a variety of cellular contexts.
Collapse
|
5
|
Holz D, Hall AR, Usukura E, Yamashiro S, Watanabe N, Vavylonis D. A mechanism with severing near barbed ends andannealing explains structure and dynamics of dendriticactin networks. eLife 2022; 11:69031. [PMID: 35670664 PMCID: PMC9252579 DOI: 10.7554/elife.69031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/04/2022] [Indexed: 11/13/2022] Open
Abstract
Single molecule imaging has shown that part of actin disassembles within a few seconds after incorporation into the dendritic filament network in lamellipodia, suggestive of frequent destabilization near barbed ends. To investigate the mechanisms behind network remodeling, we created a stochastic model with polymerization, depolymerization, branching, capping, uncapping, severing, oligomer diffusion, annealing, and debranching. We find that filament severing, enhanced near barbed ends, can explain the single molecule actin lifetime distribution, if oligomer fragments reanneal to free ends with rate constants comparable to in vitro measurements. The same mechanism leads to actin networks consistent with measured filament, end, and branch concentrations. These networks undergo structural remodeling, leading to longer filaments away from the leading edge, at the +/- 35𝑜 orientation pattern. Imaging of actin speckle lifetimes at sub-second resolution verifies frequent disassembly of newly-assembled actin. We thus propose a unified mechanism that fits a diverse set of basic lamellipodia phenomenology.
Collapse
Affiliation(s)
| | | | - Eiji Usukura
- Laboratory of Single-Molecule Cell Biology, Kyoto University
| | | | - Naoki Watanabe
- Laboratory of Single-Molecule Cell Biology, Kyoto University
| | | |
Collapse
|
6
|
Wong DCP, Lee EHC, Er J, Yow I, Koean RAG, Ang O, Xiao J, Low BC, Ding JL. Lung Cancer Induces NK Cell Contractility and Cytotoxicity Through Transcription Factor Nuclear Localization. Front Cell Dev Biol 2022; 10:871326. [PMID: 35652099 PMCID: PMC9149376 DOI: 10.3389/fcell.2022.871326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
Actomyosin-mediated cellular contractility is highly conserved for mechanotransduction and signalling. While this phenomenon has been observed in adherent cell models, whether/how contractile forces regulate the function of suspension cells like natural killer (NK) cells during cancer surveillance, is unknown. Here, we demonstrated in coculture settings that the evolutionarily conserved NK cell transcription factor, Eomes, undergoes nuclear shuttling during lung cancer cell surveillance. Biophysical and biochemical analyses revealed mechanistic enhancement of NK cell actomyosin-mediated contractility, which is associated with nuclear flattening, thus enabling nuclear entry of Eomes associated with enhanced NK cytotoxicity. We found that NK cells responded to the presumed immunosuppressive TGFβ in the NK-lung cancer coculture medium to sustain its intracellular contractility through myosin light chain phosphorylation, thereby promoting Eomes nuclear localization. Therefore, our results demonstrate that lung cancer cells provoke NK cell contractility as an early phase activation mechanism and that Eomes is a plausible mechano-responsive protein for increased NK cytotoxicity. There is scope for strategic application of actomyosin-mediated contractility modulating drugs ex vivo, to reinvigorate NK cells prior to adoptive cancer immunotherapy in vivo (177 words).
Collapse
Affiliation(s)
- Darren Chen Pei Wong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore.,Mechanobiology Institute Singapore, National University of Singapore, Singapore, Singapore
| | - E Hui Clarissa Lee
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Junzhi Er
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Ivan Yow
- Mechanobiology Institute Singapore, National University of Singapore, Singapore, Singapore
| | | | - Owen Ang
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Jingwei Xiao
- Mechanobiology Institute Singapore, National University of Singapore, Singapore, Singapore
| | - Boon Chuan Low
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore.,Mechanobiology Institute Singapore, National University of Singapore, Singapore, Singapore.,University Scholars Programme, National University of Singapore, Singapore, Singapore
| | - Jeak Ling Ding
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore.,Integrative Sciences and Engineering Programme, National University of Singapore, Singapore, Singapore
| |
Collapse
|
7
|
Rutkowski DM, Vavylonis D. Discrete mechanical model of lamellipodial actin network implements molecular clutch mechanism and generates arcs and microspikes. PLoS Comput Biol 2021; 17:e1009506. [PMID: 34662335 PMCID: PMC8553091 DOI: 10.1371/journal.pcbi.1009506] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 10/28/2021] [Accepted: 09/30/2021] [Indexed: 01/03/2023] Open
Abstract
Mechanical forces, actin filament turnover, and adhesion to the extracellular environment regulate lamellipodial protrusions. Computational and mathematical models at the continuum level have been used to investigate the molecular clutch mechanism, calculating the stress profile through the lamellipodium and around focal adhesions. However, the forces and deformations of individual actin filaments have not been considered while interactions between actin networks and actin bundles is not easily accounted with such methods. We develop a filament-level model of a lamellipodial actin network undergoing retrograde flow using 3D Brownian dynamics. Retrograde flow is promoted in simulations by pushing forces from the leading edge (due to actin polymerization), pulling forces (due to molecular motors), and opposed by viscous drag in cytoplasm and focal adhesions. Simulated networks have densities similar to measurements in prior electron micrographs. Connectivity between individual actin segments is maintained by permanent and dynamic crosslinkers. Remodeling of the network occurs via the addition of single actin filaments near the leading edge and via filament bond severing. We investigated how several parameters affect the stress distribution, network deformation and retrograde flow speed. The model captures the decrease in retrograde flow upon increase of focal adhesion strength. The stress profile changes from compression to extension across the leading edge, with regions of filament bending around focal adhesions. The model reproduces the observed reduction in retrograde flow speed upon exposure to cytochalasin D, which halts actin polymerization. Changes in crosslinker concentration and dynamics, as well as in the orientation pattern of newly added filaments demonstrate the model's ability to generate bundles of filaments perpendicular (actin arcs) or parallel (microspikes) to the protruding direction.
Collapse
|
8
|
Li Y, Munro E. Filament-guided filament assembly provides structural memory of filament alignment during cytokinesis. Dev Cell 2021; 56:2486-2500.e6. [PMID: 34480876 DOI: 10.1016/j.devcel.2021.08.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/30/2021] [Accepted: 08/13/2021] [Indexed: 10/24/2022]
Abstract
During cytokinesis, animal cells rapidly remodel the equatorial cortex to build an aligned array of actin filaments called the contractile ring. Local reorientation of filaments by active equatorial compression is thought to underlie the emergence of filament alignment during ring assembly. Here, combining single molecule analysis and modeling in one-cell C. elegans embryos, we show that filaments turnover is far too fast for reorientation of individual filaments by equatorial compression to explain the observed alignment, even if favorably oriented filaments are selectively stabilized. By tracking single formin/CYK-1::GFP particles to monitor local filament assembly, we identify a mechanism that we call filament-guided filament assembly (FGFA), in which existing filaments serve as templates to orient the growth of new filaments. FGFA sharply increases the effective lifetime of filament orientation, providing structural memory that allows cells to build highly aligned filament arrays in response to equatorial compression, despite rapid turnover of individual filaments.
Collapse
Affiliation(s)
- Younan Li
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Edwin Munro
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA; Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, IL 60637, USA; Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA.
| |
Collapse
|
9
|
Sharma M, Jiang T, Jiang ZC, Moguel-Lehmer CE, Harris TJ. Emergence of a smooth interface from growth of a dendritic network against a mechanosensitive contractile material. eLife 2021; 10:66929. [PMID: 34423780 PMCID: PMC8410080 DOI: 10.7554/elife.66929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 08/20/2021] [Indexed: 11/13/2022] Open
Abstract
Structures and machines require smoothening of raw materials. Self-organized smoothening guides cell and tissue morphogenesis and is relevant to advanced manufacturing. Across the syncytial Drosophila embryo surface, smooth interfaces form between expanding Arp2/3-based actin caps and surrounding actomyosin networks, demarcating the circumferences of nascent dome-like compartments used for pseudocleavage. We found that forming a smooth and circular boundary of the surrounding actomyosin domain requires Arp2/3 in vivo. To dissect the physical basis of this requirement, we reconstituted the interacting networks using node-based models. In simulations of actomyosin networks with local clearances in place of Arp2/3 domains, rough boundaries persisted when myosin contractility was low. With addition of expanding Arp2/3 network domains, myosin domain boundaries failed to smoothen, but accumulated myosin nodes and tension. After incorporating actomyosin mechanosensitivity, Arp2/3 network growth locally induced a surrounding contractile actomyosin ring that smoothened the interface between the cytoskeletal domains, an effect also evident in vivo. In this way, a smooth structure can emerge from the lateral interaction of irregular active materials.
Collapse
Affiliation(s)
- Medha Sharma
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Tao Jiang
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Zi Chen Jiang
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | | | - Tony Jc Harris
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| |
Collapse
|
10
|
Articular Chondrocyte Phenotype Regulation through the Cytoskeleton and the Signaling Processes That Originate from or Converge on the Cytoskeleton: Towards a Novel Understanding of the Intersection between Actin Dynamics and Chondrogenic Function. Int J Mol Sci 2021; 22:ijms22063279. [PMID: 33807043 PMCID: PMC8004672 DOI: 10.3390/ijms22063279] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 02/08/2023] Open
Abstract
Numerous studies have assembled a complex picture, in which extracellular stimuli and intracellular signaling pathways modulate the chondrocyte phenotype. Because many diseases are mechanobiology-related, this review asked to what extent phenotype regulators control chondrocyte function through the cytoskeleton and cytoskeleton-regulating signaling processes. Such information would generate leverage for advanced articular cartilage repair. Serial passaging, pro-inflammatory cytokine signaling (TNF-α, IL-1α, IL-1β, IL-6, and IL-8), growth factors (TGF-α), and osteoarthritis not only induce dedifferentiation but also converge on RhoA/ROCK/Rac1/mDia1/mDia2/Cdc42 to promote actin polymerization/crosslinking for stress fiber (SF) formation. SF formation takes center stage in phenotype control, as both SF formation and SOX9 phosphorylation for COL2 expression are ROCK activity-dependent. Explaining how it is molecularly possible that dedifferentiation induces low COL2 expression but high SF formation, this review theorized that, in chondrocyte SOX9, phosphorylation by ROCK might effectively be sidelined in favor of other SF-promoting ROCK substrates, based on a differential ROCK affinity. In turn, actin depolymerization for redifferentiation would “free-up” ROCK to increase COL2 expression. Moreover, the actin cytoskeleton regulates COL1 expression, modulates COL2/aggrecan fragment generation, and mediates a fibrogenic/catabolic expression profile, highlighting that actin dynamics-regulating processes decisively control the chondrocyte phenotype. This suggests modulating the balance between actin polymerization/depolymerization for therapeutically controlling the chondrocyte phenotype.
Collapse
|
11
|
Schreiber C, Amiri B, Heyn JCJ, Rädler JO, Falcke M. On the adhesion-velocity relation and length adaptation of motile cells on stepped fibronectin lanes. Proc Natl Acad Sci U S A 2021; 118:e2009959118. [PMID: 33483418 PMCID: PMC7869109 DOI: 10.1073/pnas.2009959118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The biphasic adhesion-velocity relation is a universal observation in mesenchymal cell motility. It has been explained by adhesion-promoted forces pushing the front and resisting motion at the rear. Yet, there is little quantitative understanding of how these forces control cell velocity. We study motion of MDA-MB-231 cells on microlanes with fields of alternating Fibronectin densities to address this topic and derive a mathematical model from the leading-edge force balance and the force-dependent polymerization rate. It reproduces quantitatively our measured adhesion-velocity relation and results with keratocytes, PtK1 cells, and CHO cells. Our results confirm that the force pushing the leading-edge membrane drives lamellipodial retrograde flow. Forces resisting motion originate along the whole cell length. All motion-related forces are controlled by adhesion and velocity, which allows motion, even with higher Fibronectin density at the rear than at the front. We find the pathway from Fibronectin density to adhesion structures to involve strong positive feedbacks. Suppressing myosin activity reduces the positive feedback. At transitions between different Fibronectin densities, steady motion is perturbed and leads to changes of cell length and front and rear velocity. Cells exhibit an intrinsic length set by adhesion strength, which, together with the length dynamics, suggests a spring-like front-rear interaction force. We provide a quantitative mechanistic picture of the adhesion-velocity relation and cell response to adhesion changes integrating force-dependent polymerization, retrograde flow, positive feedback from integrin to adhesion structures, and spring-like front-rear interaction.
Collapse
Affiliation(s)
- Christoph Schreiber
- Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität München, 80539 Munich, Germany
| | - Behnam Amiri
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Johannes C J Heyn
- Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität München, 80539 Munich, Germany
| | - Joachim O Rädler
- Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität München, 80539 Munich, Germany;
| | - Martin Falcke
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany;
- Department of Physics, Humboldt University, 12489 Berlin, Germany
| |
Collapse
|
12
|
van Haastert PJM. Unified control of amoeboid pseudopod extension in multiple organisms by branched F-actin in the front and parallel F-actin/myosin in the cortex. PLoS One 2020; 15:e0243442. [PMID: 33296414 PMCID: PMC7725310 DOI: 10.1371/journal.pone.0243442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 11/23/2020] [Indexed: 02/06/2023] Open
Abstract
The trajectory of moving eukaryotic cells depends on the kinetics and direction of extending pseudopods. The direction of pseudopods has been well studied to unravel mechanisms for chemotaxis, wound healing and inflammation. However, the kinetics of pseudopod extension-when and why do pseudopods start and stop- is equally important, but is largely unknown. Here the START and STOP of about 4000 pseudopods was determined in four different species, at four conditions and in nine mutants (fast amoeboids Dictyostelium and neutrophils, slow mesenchymal stem cells, and fungus B.d. chytrid with pseudopod and a flagellum). The START of a first pseudopod is a random event with a probability that is species-specific (23%/s for neutrophils). In all species and conditions, the START of a second pseudopod is strongly inhibited by the extending first pseudopod, which depends on parallel filamentous actin/myosin in the cell cortex. Pseudopods extend at a constant rate by polymerization of branched F-actin at the pseudopod tip, which requires the Scar complex. The STOP of pseudopod extension is induced by multiple inhibitory processes that evolve during pseudopod extension and mainly depend on the increasing size of the pseudopod. Surprisingly, no differences in pseudopod kinetics are detectable between polarized, unpolarized or chemotactic cells, and also not between different species except for small differences in numerical values. This suggests that the analysis has uncovered the fundament of cell movement with distinct roles for stimulatory branched F-actin in the protrusion and inhibitory parallel F-actin in the contractile cortex.
Collapse
|
13
|
Tan SJ, Chang AC, Anderson SM, Miller CM, Prahl LS, Odde DJ, Dunn AR. Regulation and dynamics of force transmission at individual cell-matrix adhesion bonds. SCIENCE ADVANCES 2020; 6:eaax0317. [PMID: 32440534 PMCID: PMC7228748 DOI: 10.1126/sciadv.aax0317] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 03/05/2020] [Indexed: 05/22/2023]
Abstract
Integrin-based adhesion complexes link the cytoskeleton to the extracellular matrix (ECM) and are central to the construction of multicellular animal tissues. How biological function emerges from the tens to thousands of proteins present within a single adhesion complex remains unclear. We used fluorescent molecular tension sensors to visualize force transmission by individual integrins in living cells. These measurements revealed an underlying functional modularity in which integrin class controlled adhesion size and ECM ligand specificity, while the number and type of connections between integrins and F-actin determined the force per individual integrin. In addition, we found that most integrins existed in a state of near-mechanical equilibrium, a result not predicted by existing models of cytoskeletal force transduction. A revised model that includes reversible cross-links within the F-actin network can account for this result and suggests one means by which cellular mechanical homeostasis can arise at the molecular level.
Collapse
Affiliation(s)
- Steven J. Tan
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Alice C. Chang
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Sarah M. Anderson
- Department of Biomedical Engineering and Physical Sciences–Oncology Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Cayla M. Miller
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Louis S. Prahl
- Department of Biomedical Engineering and Physical Sciences–Oncology Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - David J. Odde
- Department of Biomedical Engineering and Physical Sciences–Oncology Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alexander R. Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
- Corresponding author.
| |
Collapse
|
14
|
Kobb AB, Rothenberg KE, Fernandez-Gonzalez R. Actin and myosin dynamics are independent during Drosophila embryonic wound repair. Mol Biol Cell 2019; 30:2901-2912. [PMID: 31553671 PMCID: PMC6822589 DOI: 10.1091/mbc.e18-11-0703] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Collective cell movements play a central role in embryonic development, tissue repair, and metastatic disease. Cell movements are often coordinated by supracellular networks formed by the cytoskeletal protein actin and the molecular motor nonmuscle myosin II. During wound closure in the embryonic epidermis, the cells around the wound migrate collectively into the damaged region. In Drosophila embryos, mechanical tension stabilizes myosin at the wound edge, facilitating the assembly of a supracellular myosin cable around the wound that coordinates cell migration. Here, we show that actin is also stabilized at the wound edge. However, loss of tension or myosin activity does not affect the dynamics of actin at the wound margin. Conversely, pharmacological stabilization of actin does not affect myosin levels or dynamics around the wound. Together, our data suggest that actin and myosin are independently regulated during embryonic wound closure, thus conferring robustness to the embryonic wound healing response.
Collapse
Affiliation(s)
- Anna B Kobb
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada.,Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Katheryn E Rothenberg
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada.,Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Rodrigo Fernandez-Gonzalez
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada.,Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada.,Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| |
Collapse
|
15
|
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.
Collapse
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
| |
Collapse
|
16
|
Rahikainen R, Öhman T, Turkki P, Varjosalo M, Hytönen VP. Talin-mediated force transmission and talin rod domain unfolding independently regulate adhesion signaling. J Cell Sci 2019; 132:jcs226514. [PMID: 30837291 DOI: 10.1242/jcs.226514] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 02/26/2019] [Indexed: 12/29/2022] Open
Abstract
Talin protein is one of the key components in integrin-mediated adhesion complexes. Talins transmit mechanical forces between β-integrin and actin, and regulate adhesion complex composition and signaling through the force-regulated unfolding of talin rod domain. Using modified talin proteins, we demonstrate that these functions contribute to different cellular processes and can be dissected. The transmission of mechanical forces regulates adhesion complex composition and phosphotyrosine signaling even in the absence of the mechanically regulated talin rod subdomains. However, the presence of the rod subdomains and their mechanical activation are required for the reinforcement of the adhesion complex, cell polarization and migration. Talin rod domain unfolding was also found to be essential for the generation of cellular signaling anisotropy, since both insufficient and excess activity of the rod domain severely inhibited cell polarization. Utilizing proteomics tools, we identified adhesome components that are recruited and activated either in a talin rod-dependent manner or independently of the rod subdomains. This study clarifies the division of roles between the force-regulated unfolding of a talin protein (talin 1) and its function as a physical linker between integrins and the cytoskeleton.
Collapse
Affiliation(s)
- Rolle Rahikainen
- Faculty of Medicine and Health Technology and BioMediTech, Tampere University, Tampere 33014, Finland
- Fimlab Laboratories, Tampere 33520, Finland
| | - Tiina Öhman
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Paula Turkki
- Faculty of Medicine and Health Technology and BioMediTech, Tampere University, Tampere 33014, Finland
- Fimlab Laboratories, Tampere 33520, Finland
| | - Markku Varjosalo
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Vesa P Hytönen
- Faculty of Medicine and Health Technology and BioMediTech, Tampere University, Tampere 33014, Finland
- Fimlab Laboratories, Tampere 33520, Finland
| |
Collapse
|
17
|
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.
Collapse
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.
| |
Collapse
|
18
|
Tang VW. Cell-cell adhesion interface: orthogonal and parallel forces from contraction, protrusion, and retraction. F1000Res 2018; 7. [PMID: 30345009 PMCID: PMC6173117 DOI: 10.12688/f1000research.15860.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/19/2018] [Indexed: 01/22/2023] Open
Abstract
The epithelial lateral membrane plays a central role in the integration of intercellular signals and, by doing so, is a principal determinant in the emerging properties of epithelial tissues. Mechanical force, when applied to the lateral cell-cell interface, can modulate the strength of adhesion and influence intercellular dynamics. Yet the relationship between mechanical force and epithelial cell behavior is complex and not completely understood. This commentary aims to provide an investigative look at the usage of cellular forces at the epithelial cell-cell adhesion interface.
Collapse
Affiliation(s)
- Vivian W Tang
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, IL, 61801, USA
| |
Collapse
|