1
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Harrell MA, Liu Z, Campbell BF, Chinsen O, Hong T, Das M. Arp2/3-dependent endocytosis ensures Cdc42 oscillations by removing Pak1-mediated negative feedback. J Cell Biol 2024; 223:e202311139. [PMID: 39012625 PMCID: PMC11259211 DOI: 10.1083/jcb.202311139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 05/10/2024] [Accepted: 07/01/2024] [Indexed: 07/17/2024] Open
Abstract
The GTPase Cdc42 regulates polarized growth in most eukaryotes. In the bipolar yeast Schizosaccharomyces pombe, Cdc42 activation cycles periodically at sites of polarized growth. These periodic cycles are caused by alternating positive feedback and time-delayed negative feedback loops. At each polarized end, negative feedback is established when active Cdc42 recruits the Pak1 kinase to prevent further Cdc42 activation. It is unclear how Cdc42 activation returns to each end after Pak1-dependent negative feedback. We find that disrupting branched actin-mediated endocytosis disables Cdc42 reactivation at the cell ends. Using experimental and mathematical approaches, we show that endocytosis-dependent Pak1 removal from the cell ends allows the Cdc42 activator Scd1 to return to that end to enable reactivation of Cdc42. Moreover, we show that Pak1 elicits its own removal via activation of endocytosis. These findings provide a deeper insight into the self-organization of Cdc42 regulation and reveal previously unknown feedback with endocytosis in the establishment of cell polarity.
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Affiliation(s)
| | - Ziyi Liu
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | | | - Olivia Chinsen
- Biology Department, Boston College, Chestnut Hill, MA, USA
| | - Tian Hong
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Maitreyi Das
- Biology Department, Boston College, Chestnut Hill, MA, USA
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2
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Yan Q, Gomis Perez C, Karatekin E. Cell Membrane Tension Gradients, Membrane Flows, and Cellular Processes. Physiology (Bethesda) 2024; 39:0. [PMID: 38501962 DOI: 10.1152/physiol.00007.2024] [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: 01/30/2024] [Revised: 03/18/2024] [Accepted: 03/18/2024] [Indexed: 03/20/2024] Open
Abstract
Cell membrane tension affects and is affected by many fundamental cellular processes, yet it is poorly understood. Recent experiments show that membrane tension can propagate at vastly different speeds in different cell types, reflecting physiological adaptations. Here we briefly review the current knowledge about membrane tension gradients, membrane flows, and their physiological context.
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Affiliation(s)
- Qi Yan
- Cellular and Molecular Physiology, Yale University, New Haven, Connecticut, United States
- Nanobiology Institute, Yale University, West Haven, Connecticut, United States
| | - Carolina Gomis Perez
- Cellular and Molecular Physiology, Yale University, New Haven, Connecticut, United States
- Nanobiology Institute, Yale University, West Haven, Connecticut, United States
| | - Erdem Karatekin
- Cellular and Molecular Physiology, Yale University, New Haven, Connecticut, United States
- Nanobiology Institute, Yale University, West Haven, Connecticut, United States
- Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States
- Wu Tsai Institute, Yale University, New Haven, Connecticut, United States
- Saints-Pères Paris Institute for the Neurosciences (SPPIN), Centre National de la Recherche Scientifique (CNRS), Paris, France
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3
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Sakai K, Aoki K, Goto Y. Live-cell fluorescence imaging and optogenetic control of PKA kinase activity in fission yeast Schizosaccharomyces pombe. Yeast 2024; 41:349-363. [PMID: 38583078 DOI: 10.1002/yea.3937] [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: 01/16/2024] [Revised: 02/21/2024] [Accepted: 03/20/2024] [Indexed: 04/08/2024] Open
Abstract
The cAMP-PKA signaling pathway plays a crucial role in sensing and responding to nutrient availability in the fission yeast Schizosaccharomyces pombe. This pathway monitors external glucose levels to control cell growth and sexual differentiation. However, the temporal dynamics of the cAMP-PKA pathway in response to external stimuli remains unclear mainly due to the lack of tools to quantitatively visualize the activity of the pathway. Here, we report the development of the kinase translocation reporter (KTR)-based biosensor spPKA-KTR1.0, which allows us to measure the dynamics of PKA activity in fission yeast cells. The spPKA-KTR1.0 is derived from the transcription factor Rst2, which translocates from the nucleus to the cytoplasm upon PKA activation. We found that spPKA-KTR1.0 translocates between the nucleus and cytoplasm in a cAMP-PKA pathway-dependent manner, indicating that the spPKA-KTR1.0 is a reliable indicator of the PKA activity in fission yeast cells. In addition, we implemented a system that simultaneously visualizes and manipulates the cAMP-PKA signaling dynamics by introducing bPAC, a photoactivatable adenylate cyclase, in combination with spPKA-KTR1.0. This system offers an opportunity for investigating the role of the signaling dynamics of the cAMP-PKA pathway in fission yeast cells with higher temporal resolution.
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Affiliation(s)
- Keiichiro Sakai
- Quantitative Biology Research Group, Department of Creative Research, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi, Japan
- Division of Quantitative Biology, National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi, Japan
| | - Kazuhiro Aoki
- Quantitative Biology Research Group, Department of Creative Research, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi, Japan
- Division of Quantitative Biology, National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi, Japan
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi, Japan
- Center for Living Systems Information Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
- Division of Integrated Life Science, Department of Gene Mechanisms, Laboratory of Cell Cycle Regulation, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Yuhei Goto
- Quantitative Biology Research Group, Department of Creative Research, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi, Japan
- Division of Quantitative Biology, National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi, Japan
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi, Japan
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4
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Bement WM, Goryachev AB, Miller AL, von Dassow G. Patterning of the cell cortex by Rho GTPases. Nat Rev Mol Cell Biol 2024; 25:290-308. [PMID: 38172611 DOI: 10.1038/s41580-023-00682-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2023] [Indexed: 01/05/2024]
Abstract
The Rho GTPases - RHOA, RAC1 and CDC42 - are small GTP binding proteins that regulate basic biological processes such as cell locomotion, cell division and morphogenesis by promoting cytoskeleton-based changes in the cell cortex. This regulation results from active (GTP-bound) Rho GTPases stimulating target proteins that, in turn, promote actin assembly and myosin 2-based contraction to organize the cortex. This basic regulatory scheme, well supported by in vitro studies, led to the natural assumption that Rho GTPases function in vivo in an essentially linear matter, with a given process being initiated by GTPase activation and terminated by GTPase inactivation. However, a growing body of evidence based on live cell imaging, modelling and experimental manipulation indicates that Rho GTPase activation and inactivation are often tightly coupled in space and time via signalling circuits and networks based on positive and negative feedback. In this Review, we present and discuss this evidence, and we address one of the fundamental consequences of coupled activation and inactivation: the ability of the Rho GTPases to self-organize, that is, direct their own transition from states of low order to states of high order. We discuss how Rho GTPase self-organization results in the formation of diverse spatiotemporal cortical patterns such as static clusters, oscillatory pulses, travelling wave trains and ring-like waves. Finally, we discuss the advantages of Rho GTPase self-organization and pattern formation for cell function.
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Affiliation(s)
- William M Bement
- Center for Quantitative Cell Imaging, Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Andrew B Goryachev
- Center for Engineering Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
| | - Ann L Miller
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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5
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Barbieri S, Gotta M. Order from chaos: cellular asymmetries explained with modelling. Trends Cell Biol 2024; 34:122-135. [PMID: 37574346 DOI: 10.1016/j.tcb.2023.06.009] [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: 03/21/2023] [Revised: 06/26/2023] [Accepted: 06/28/2023] [Indexed: 08/15/2023]
Abstract
Molecules inside cells are subject to physical forces and undergo biochemical interactions, continuously changing their physical properties and dynamics. Despite this, cells achieve highly ordered molecular patterns that are crucial to regulate various cellular functions and to specify cell fate. In the Caenorhabditis elegans one-cell embryo, protein asymmetries are established in the narrow time window of a cell division. What are the mechanisms that allow molecules to establish asymmetries, defying the randomness imposed by Brownian motion? Mathematical and computational models have paved the way to the understanding of protein dynamics up to the 'single-molecule level' when resolution represents an issue for precise experimental measurements. Here we review the models that interpret cortical and cytoplasmic asymmetries in the one-cell C. elegans embryo.
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Affiliation(s)
- Sofia Barbieri
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland.
| | - Monica Gotta
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland
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6
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Honerkamp-Smith AR. Forces and Flows at Cell Surfaces. J Membr Biol 2023; 256:331-340. [PMID: 37773346 PMCID: PMC10947748 DOI: 10.1007/s00232-023-00293-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 09/08/2023] [Indexed: 10/01/2023]
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7
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Harrell M, Liu Z, Campbell BF, Chinsen O, Hong T, Das M. The Arp2/3 complex promotes periodic removal of Pak1-mediated negative feedback to facilitate anticorrelated Cdc42 oscillations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.566261. [PMID: 38106068 PMCID: PMC10723479 DOI: 10.1101/2023.11.08.566261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The conserved GTPase Cdc42 is a major regulator of polarized growth in most eukaryotes. Cdc42 periodically cycles between active and inactive states at sites of polarized growth. These periodic cycles are caused by positive feedback and time-delayed negative feedback loops. In the bipolar yeast S. pombe, both growing ends must regulate Cdc42 activity. At each cell end, Cdc42 activity recruits the Pak1 kinase which prevents further Cdc42 activation thus establishing negative feedback. It is unclear how Cdc42 activation returns to the end after Pak1-dependent negative feedback. Using genetic and chemical perturbations, we find that disrupting branched actin-mediated endocytosis disables Cdc42 reactivation at the cell ends. With our experimental data and mathematical models, we show that endocytosis-dependent Pak1 removal from the cell ends allows the Cdc42 activator Scd1 to return to that end to enable reactivation of Cdc42. Moreover, we show that Pak1 elicits its own removal via activation of endocytosis. In agreement with these observations, our model and experimental data show that in each oscillatory cycle, Cdc42 activation increases followed by an increase in Pak1 recruitment at that end. These findings provide a deeper insight into the self-organization of Cdc42 regulation and reveal previously unknown feedback with endocytosis in the establishment of cell polarity.
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Affiliation(s)
- Marcus Harrell
- Biology Department, Boston College, Chestnut Hill, MA, 02467
| | - Ziyi Liu
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, TN, 37916
| | | | - Olivia Chinsen
- Biology Department, Boston College, Chestnut Hill, MA, 02467
| | - Tian Hong
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, TN, 37916
| | - Maitreyi Das
- Biology Department, Boston College, Chestnut Hill, MA, 02467
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8
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Opalko H, Geng S, Hall AR, Vavylonis D, Moseley JB. Design principles of Cdr2 node patterns in fission yeast cells. Mol Biol Cell 2023; 34:br18. [PMID: 37610834 PMCID: PMC10559309 DOI: 10.1091/mbc.e23-04-0135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/24/2023] [Accepted: 08/14/2023] [Indexed: 08/25/2023] Open
Abstract
Pattern-forming networks have diverse roles in cell biology. Rod-shaped fission yeast cells use pattern formation to control the localization of mitotic signaling proteins and the cytokinetic ring. During interphase, the kinase Cdr2 forms membrane-bound multiprotein complexes termed nodes, which are positioned in the cell middle due in part to the node inhibitor Pom1 enriched at cell tips. Node positioning is important for timely cell cycle progression and positioning of the cytokinetic ring. Here, we combined experimental and modeling approaches to investigate pattern formation by the Pom1-Cdr2 system. We found that Cdr2 nodes accumulate near the nucleus, and Cdr2 undergoes nucleocytoplasmic shuttling when cortical anchoring is reduced. We generated particle-based simulations based on tip inhibition, nuclear positioning, and cortical anchoring. We tested model predictions by investigating Pom1-Cdr2 localization patterns after perturbing each positioning mechanism, including in both anucleate and multinucleated cells. Experiments show that tip inhibition and cortical anchoring alone are sufficient for the assembly and positioning of nodes in the absence of the nucleus, but that the nucleus and Pom1 facilitate the formation of unexpected node patterns in multinucleated cells. These findings have implications for spatial control of cytokinesis by nodes and for spatial patterning in other biological systems.
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Affiliation(s)
- Hannah Opalko
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Shuhan Geng
- Department of Physics, Lehigh University, Bethlehem, PA 18016
| | - Aaron R. Hall
- Department of Physics, Lehigh University, Bethlehem, PA 18016
| | - Dimitrios Vavylonis
- Department of Physics, Lehigh University, Bethlehem, PA 18016
- Center for Computational Biology, Flatiron Institute, New York, NY 10010
| | - James B. Moseley
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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9
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Guan K, Curtis ER, Lew DJ, Elston TC. Particle-based simulations reveal two positive feedback loops allow relocation and stabilization of the polarity site during yeast mating. PLoS Comput Biol 2023; 19:e1011523. [PMID: 37782676 PMCID: PMC10569529 DOI: 10.1371/journal.pcbi.1011523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 10/12/2023] [Accepted: 09/17/2023] [Indexed: 10/04/2023] Open
Abstract
Many cells adjust the direction of polarized growth or migration in response to external directional cues. The yeast Saccharomyces cerevisiae orient their cell fronts (also called polarity sites) up pheromone gradients in the course of mating. However, the initial polarity site is often not oriented towards the eventual mating partner, and cells relocate the polarity site in an indecisive manner before developing a stable orientation. During this reorientation phase, the polarity site displays erratic assembly-disassembly behavior and moves around the cell cortex. The mechanisms underlying this dynamic behavior remain poorly understood. Particle-based simulations of the core polarity circuit revealed that molecular-level fluctuations are unlikely to overcome the strong positive feedback required for polarization and generate relocating polarity sites. Surprisingly, inclusion of a second pathway that promotes polarity site orientation generated relocating polarity sites with properties similar to those observed experimentally. This pathway forms a second positive feedback loop involving the recruitment of receptors to the cell membrane and couples polarity establishment to gradient sensing. This second positive feedback loop also allows cells to stabilize their polarity site once the site is aligned with the pheromone gradient.
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Affiliation(s)
- Kaiyun Guan
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Erin R. Curtis
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Daniel J. Lew
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Timothy C. Elston
- Department of Pharmacology and Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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10
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Rutkowski DM, Vincenzetti V, Vavylonis D, Martin SG. Cdc42 mobility and membrane flows regulate fission yeast cell shape and survival. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.21.550042. [PMID: 37503115 PMCID: PMC10370159 DOI: 10.1101/2023.07.21.550042] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Local Cdc42 GTPase activation promotes polarized exocytosis, resulting in membrane flows that deplete low-mobility membrane-associated proteins from the growth region. To investigate the self-organizing properties of the Cdc42 secretion-polarization system under membrane flow, we developed a reaction-diffusion particle model. The model includes positive feedback activation of Cdc42, hydrolysis by GTPase-activating proteins (GAPs), and flow-induced displacement by exo/endocytosis. Simulations show how polarization relies on flow-induced depletion of low mobility GAPs. To probe the role of Cdc42 mobility in the fission yeast Schizosaccharomyces pombe, we changed its membrane binding properties by replacing its prenylation site with 1, 2 or 3 repeats of the Rit1 C terminal membrane binding domain (ritC), yielding alleles with progressively lower unbinding and diffusion rates. Concordant modelling predictions and experimental observations show that lower Cdc42 mobility results in lower Cdc42 activation level and wider patches. Indeed, while Cdc42-1ritC cells are viable and polarized, Cdc42-2ritC polarize poorly and Cdc42-3ritC is inviable. The model further predicts that GAP depletion increases Cdc42 activity at the expense of loss of polarization. Experiments confirm this prediction, as deletion of Cdc42 GAPs restores viability to Cdc42-3ritC cells. Our combined experimental and modelling studies demonstrate how membrane flows are an integral part of Cdc42-driven pattern formation.
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Affiliation(s)
| | | | | | - Sophie G. Martin
- Department of Fundamental Microbiology, University of Lausanne, Switzerland
- Department of Molecular and Cellular Biology, University of Geneva, Quai Ernest-Ansermet 30, 1205 Geneva
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11
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Opalko H, Geng S, Hall AR, Vavylonis D, Moseley JB. Design principles of Cdr2 node patterns in fission yeast cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.537536. [PMID: 37131752 PMCID: PMC10153186 DOI: 10.1101/2023.04.19.537536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Pattern forming networks have diverse roles in cell biology. Rod-shaped fission yeast cells use pattern formation to control the localization of mitotic signaling proteins and the cytokinetic ring. During interphase, the kinase Cdr2 forms membrane-bound multiprotein complexes termed nodes, which are positioned in the cell middle due in part to the node inhibitor Pom1 enriched at cell tips. Node positioning is important for timely cell cycle progression and positioning of the cytokinetic ring. Here, we combined experimental and modeling approaches to investigate pattern formation by the Pom1-Cdr2 system. We found that Cdr2 nodes accumulate near the nucleus, and Cdr2 undergoes nucleocytoplasmic shuttling when cortical anchoring is reduced. We generated particle-based simulations based on tip inhibition, nuclear positioning, and cortical anchoring. We tested model predictions by investigating Pom1-Cdr2 localization patterns after perturbing each positioning mechanism, including in both anucleate and multinucleated cells. Experiments show that tip inhibition and cortical anchoring alone are sufficient for the assembly and positioning of nodes in the absence of the nucleus, but that the nucleus and Pom1 facilitate the formation of unexpected node patterns in multinucleated cells. These findings have implications for spatial control of cytokinesis by nodes and for spatial patterning in other biological systems.
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Affiliation(s)
- Hannah Opalko
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, NH
| | - Shuhan Geng
- Department of Physics, Lehigh University, Bethlehem, PA
| | - Aaron R. Hall
- Department of Physics, Lehigh University, Bethlehem, PA
| | - Dimitrios Vavylonis
- Department of Physics, Lehigh University, Bethlehem, PA
- Center for Computational Biology, Flatiron Institute, New York, NY
| | - James B. Moseley
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, NH
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12
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Ratajczak AM, Sasidharan S, Rivera Gonzalez XI, Miller EJ, Socrier L, Anthony AA, Honerkamp-Smith AR. Measuring flow-mediated protein drift across stationary supported lipid bilayers. Biophys J 2023; 122:1720-1731. [PMID: 37020419 PMCID: PMC10183372 DOI: 10.1016/j.bpj.2023.03.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 03/13/2023] [Accepted: 03/29/2023] [Indexed: 04/07/2023] Open
Abstract
Fluid flow near biological membranes influences cell functions such as development, motility, and environmental sensing. Flow can laterally transport extracellular membrane proteins located at the cell-fluid interface. To determine whether this transport contributes to flow signaling in cells, quantitative knowledge of the forces acting on membrane proteins is required. Here, we demonstrate a method for measuring flow-mediated lateral transport of lipid-anchored proteins. We rupture giant unilamellar vesicles to form discrete patches of supported membrane inside rectangular microchannels and then allow proteins to bind to the upper surface of the membrane. While applying flow, we observe the formation of protein concentration gradients that span the membrane patch. By observing how these gradients dynamically respond to changes in applied shear stress, we determine the flow mobility of the lipid-anchored protein. We use simplified model membranes and proteins to demonstrate our method's sensitivity and reproducibility. Our intention was to design a quantitative, reliable method and analysis for protein mobility that we will use to compare flow transport for a variety of proteins, lipid anchors, and membranes in model systems and on living cells.
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Affiliation(s)
| | | | | | - Ethan J Miller
- Department of Physics, Lehigh University, Bethlehem, Pennsylvania
| | - Larissa Socrier
- Department of Physics, Lehigh University, Bethlehem, Pennsylvania
| | - Autumn A Anthony
- Department of Physics, Lehigh University, Bethlehem, Pennsylvania
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13
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Gerganova V, Martin SG. Going with the membrane flow: the impact of polarized secretion on bulk plasma membrane flows. FEBS J 2023; 290:669-676. [PMID: 34797957 PMCID: PMC10078680 DOI: 10.1111/febs.16287] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/07/2021] [Accepted: 11/18/2021] [Indexed: 02/04/2023]
Abstract
Even the simplest cells show a remarkable degree of intracellular patterning. Like developing multicellular organisms, single cells break symmetry to establish polarity axes, pattern their cortex and interior, and undergo morphogenesis to acquire sometimes complex shapes. Symmetry-breaking and molecular patterns can be established through coupling of negative and positive feedback reactions in biochemical reaction-diffusion systems. Physical forces, perhaps best studied in the contraction of the metazoan acto-myosin cortex, which induces cortical and cytoplasmic flows, also serve to pattern-associated components. A less investigated physical perturbation is the in-plane flow of plasma membrane material caused by membrane trafficking. In this review, we discuss how bulk membrane flows can be generated at sites of active polarized secretion and growth, how they affect the distribution of membrane-associated proteins, and how they may be harnessed for patterning and directional movement in cells across the tree of life.
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Affiliation(s)
- Veneta Gerganova
- Department of Fundamental Microbiology, University of Lausanne, Switzerland
| | - Sophie G Martin
- Department of Fundamental Microbiology, University of Lausanne, Switzerland
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14
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Weng X, Wang H. Apical vesicles: Social networking at the pollen tube tip. REPRODUCTION AND BREEDING 2022. [DOI: 10.1016/j.repbre.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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15
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Milas A, de-Carvalho J, Telley IA. Follicle cell contact maintains main body axis polarity in the Drosophila melanogaster oocyte. J Cell Biol 2022; 222:213703. [PMID: 36409222 PMCID: PMC9682419 DOI: 10.1083/jcb.202209052] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/02/2022] [Accepted: 11/04/2022] [Indexed: 11/23/2022] Open
Abstract
In Drosophila melanogaster, the anterior-posterior body axis is maternally established and governed by differential localization of partitioning defective (Par) proteins within the oocyte. At mid-oogenesis, Par-1 accumulates at the oocyte posterior end, while Par-3/Bazooka is excluded there but maintains its localization along the remaining oocyte cortex. Past studies have proposed the need for somatic cells at the posterior end to initiate oocyte polarization by providing a trigger signal. To date, neither the molecular identity nor the nature of the signal is known. Here, we provide evidence that mechanical contact of posterior follicle cells (PFCs) with the oocyte cortex causes the posterior exclusion of Bazooka and maintains oocyte polarity. We show that Bazooka prematurely accumulates exclusively where posterior follicle cells have been mechanically detached or ablated. Furthermore, we provide evidence that PFC contact maintains Par-1 and oskar mRNA localization and microtubule cytoskeleton polarity in the oocyte. Our observations suggest that cell-cell contact mechanics modulates Par protein binding sites at the oocyte cortex.
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Affiliation(s)
- Ana Milas
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Rua da Quinta Grande, Portugal
| | - Jorge de-Carvalho
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Rua da Quinta Grande, Portugal
| | - Ivo A. Telley
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, Rua da Quinta Grande, Portugal,Correspondence to Ivo A. Telley:
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16
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Wei W, Zheng B, Zheng S, Wu D, Chu Y, Zhang S, Wang D, Ma X, Liu X, Yao X, Fu C. The Cdc42 GAP Rga6 promotes monopolar outgrowth of spores. J Biophys Biochem Cytol 2022; 222:213678. [PMID: 36355349 PMCID: PMC9652770 DOI: 10.1083/jcb.202202064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 09/01/2022] [Accepted: 10/18/2022] [Indexed: 11/11/2022] Open
Abstract
The molecular mechanisms underlying the establishment of the monopolar growth of fission yeast spores have been less characterized. Here, we report that the Cdc42 GTPase-activating protein (GAP) Rga6 is required for promoting monopolar growth during spore germination. The absence of Rga6 increases the number of spores that grow in a bipolar fashion. Rga6 decorates the non-growing cortical region, binds phosphatidylinositol 4,5-bisphosphate, and colocalizes with the phosphatidylinositol 4,5-bisphosphate-binding protein Opy1. Overexpression of Opy1 diminishes the cortical localization of Rga6. The characteristic localization of Rga6 on the cell cortex depends on the C-terminal PBR region of Rga6. Moreover, engineered chimera composed of the Rga6 C-terminal PBR region fused to the GAP domain of Rga3 or Rga4 are sufficient to rescue the spore growth phenotype caused by the absence of Rga6. Hence, our work establishes a paradigm in which the lipid composition of the plasma membrane directs polarized cell growth by specifying the cortical localization of a GAP protein.
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Affiliation(s)
- Wenfan Wei
- MOE Key Laboratory for Cellular Dynamics and School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Biyu Zheng
- MOE Key Laboratory for Cellular Dynamics and School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Shengnan Zheng
- MOE Key Laboratory for Cellular Dynamics and School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Daqiang Wu
- MOE Key Laboratory for Cellular Dynamics and School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yongkang Chu
- MOE Key Laboratory for Cellular Dynamics and School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Shenghao Zhang
- MOE Key Laboratory for Cellular Dynamics and School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Dongmei Wang
- MOE Key Laboratory for Cellular Dynamics and School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Xiaopeng Ma
- Department of General Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Xing Liu
- MOE Key Laboratory for Cellular Dynamics and School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Xuebiao Yao
- MOE Key Laboratory for Cellular Dynamics and School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China,Xuebiao Yao:
| | - Chuanhai Fu
- MOE Key Laboratory for Cellular Dynamics and School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China,Correspondence to Chuanhai Fu:
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17
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Condensation of the fusion focus by the intrinsically disordered region of the formin Fus1 is essential for cell-cell fusion. Curr Biol 2022; 32:4752-4761.e10. [DOI: 10.1016/j.cub.2022.09.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 08/18/2022] [Accepted: 09/13/2022] [Indexed: 11/06/2022]
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18
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Radler P, Baranova N, Caldas P, Sommer C, López-Pelegrín M, Michalik D, Loose M. In vitro reconstitution of Escherichia coli divisome activation. Nat Commun 2022; 13:2635. [PMID: 35550516 PMCID: PMC9098913 DOI: 10.1038/s41467-022-30301-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: 11/22/2021] [Accepted: 04/25/2022] [Indexed: 01/02/2023] Open
Abstract
The actin-homologue FtsA is essential for E. coli cell division, as it links FtsZ filaments in the Z-ring to transmembrane proteins. FtsA is thought to initiate cell constriction by switching from an inactive polymeric to an active monomeric conformation, which recruits downstream proteins and stabilizes the Z-ring. However, direct biochemical evidence for this mechanism is missing. Here, we use reconstitution experiments and quantitative fluorescence microscopy to study divisome activation in vitro. By comparing wild-type FtsA with FtsA R286W, we find that this hyperactive mutant outperforms FtsA WT in replicating FtsZ treadmilling dynamics, FtsZ filament stabilization and recruitment of FtsN. We could attribute these differences to a faster exchange and denser packing of FtsA R286W below FtsZ filaments. Using FRET microscopy, we also find that FtsN binding promotes FtsA self-interaction. We propose that in the active divisome FtsA and FtsN exist as a dynamic copolymer that follows treadmilling filaments of FtsZ. In E. coli, FtsA and FtsZ control the place and time of cell division. Here, the authors use in vitro experiments to show how FtsA can follow FtsZ treadmilling and that downstream proteins form dynamic copolymers with FtsA to initiate division.
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Affiliation(s)
- Philipp Radler
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Natalia Baranova
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria.,University of Vienna, Department of Pharmaceutical Sciences, Vienna, Austria
| | - Paulo Caldas
- UCIBIO-Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade Nova de Lisboa, Caparica, Portugal
| | - Christoph Sommer
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Mar López-Pelegrín
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - David Michalik
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Martin Loose
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria.
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19
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Rich-Robinson J, Russell A, Mancini E, Das M. Cdc42 reactivation at growth sites is regulated by local cell-cycle-dependent loss of its GTPase-activating protein Rga4 in fission yeast. J Cell Sci 2021; 134:272049. [PMID: 34523683 DOI: 10.1242/jcs.259291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 12/18/2022] Open
Abstract
In fission yeast, polarized cell growth stops during division and resumes after cytokinesis completes and cells separate. It is unclear how growth reactivation is timed to occur immediately after cell separation. We uncoupled these sequential events by delaying cytokinesis with a temporary Latrunculin A treatment. Mitotic cells recovering from treatment initiate end growth during septation, displaying a polar elongation simultaneous with septation (PrESS) phenotype. PrESS cell ends reactivate Cdc42, a major regulator of polarized growth, during septation, but at a fixed time after anaphase B. A candidate screen implicates Rga4, a negative regulator of Cdc42, in this process. We show that Rga4 appears punctate at the cell sides during G2, but is diffuse during mitosis, extending to the ends. Although the Morphogenesis Orb6 (MOR) pathway is known to promote cell separation and growth by activating protein synthesis, we find that, for polarized growth, removal of Rga4 from the ends is also necessary. Therefore, we propose that growth resumes after division once the MOR pathway is activated and the ends lose Rga4 in a cell-cycle-dependent manner.
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Affiliation(s)
- Julie Rich-Robinson
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Afton Russell
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Eleanor Mancini
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Maitreyi Das
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
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