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Chikireddy J, Lengagne L, Le Borgne R, Durieu C, Wioland H, Romet-Lemonne G, Jégou A. Fascin-induced bundling protects actin filaments from disassembly by cofilin. J Cell Biol 2024; 223:e202312106. [PMID: 38497788 PMCID: PMC10949937 DOI: 10.1083/jcb.202312106] [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: 12/20/2023] [Revised: 02/26/2024] [Accepted: 02/29/2024] [Indexed: 03/19/2024] Open
Abstract
Actin filament turnover plays a central role in shaping actin networks, yet the feedback mechanism between network architecture and filament assembly dynamics remains unclear. The activity of ADF/cofilin, the main protein family responsible for filament disassembly, has been mainly studied at the single filament level. This study unveils that fascin, by crosslinking filaments into bundles, strongly slows down filament disassembly by cofilin. We show that this is due to a markedly slower initiation of the first cofilin clusters, which occurs up to 100-fold slower on large bundles compared with single filaments. In contrast, severing at cofilin cluster boundaries is unaffected by fascin bundling. After the formation of an initial cofilin cluster on a filament within a bundle, we observed the local removal of fascin. Notably, the formation of cofilin clusters on adjacent filaments is highly enhanced, locally. We propose that this interfilament cooperativity arises from the local propagation of the cofilin-induced change in helicity from one filament to the other filaments of the bundle. Overall, taking into account all the above reactions, we reveal that fascin crosslinking slows down the disassembly of actin filaments by cofilin. These findings highlight the important role played by crosslinkers in tuning actin network turnover by modulating the activity of other regulatory proteins.
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Affiliation(s)
| | - Léana Lengagne
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Rémi Le Borgne
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Catherine Durieu
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Hugo Wioland
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | | | - Antoine Jégou
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
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2
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Chakraborty A, Nathan A, Orcholski M, Agarwal S, Shamskhou EA, Auer N, Mitra A, Guardado ES, Swaminathan G, Condon DF, Yu J, McCarra M, Juul NH, Mallory A, Guzman-Hernandez RA, Yuan K, Rojas V, Crossno JT, Yung LM, Yu PB, Spencer T, Winn RA, Frump A, Karoor V, Lahm T, Hedlin H, Fineman JR, Lafyatis R, Knutsen CNF, Alvira CM, Cornfield DN, de Jesus Perez VA. Wnt7a deficit is associated with dysfunctional angiogenesis in pulmonary arterial hypertension. Eur Respir J 2023; 61:2201625. [PMID: 37024132 PMCID: PMC10259331 DOI: 10.1183/13993003.01625-2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 02/21/2023] [Indexed: 04/08/2023]
Abstract
INTRODUCTION Pulmonary arterial hypertension (PAH) is characterised by loss of microvessels. The Wnt pathways control pulmonary angiogenesis but their role in PAH is incompletely understood. We hypothesised that Wnt activation in pulmonary microvascular endothelial cells (PMVECs) is required for pulmonary angiogenesis, and its loss contributes to PAH. METHODS Lung tissue and PMVECs from healthy and PAH patients were screened for Wnt production. Global and endothelial-specific Wnt7a -/- mice were generated and exposed to chronic hypoxia and Sugen-hypoxia (SuHx). RESULTS Healthy PMVECs demonstrated >6-fold Wnt7a expression during angiogenesis that was absent in PAH PMVECs and lungs. Wnt7a expression correlated with the formation of tip cells, a migratory endothelial phenotype critical for angiogenesis. PAH PMVECs demonstrated reduced vascular endothelial growth factor (VEGF)-induced tip cell formation as evidenced by reduced filopodia formation and motility, which was partially rescued by recombinant Wnt7a. We discovered that Wnt7a promotes VEGF signalling by facilitating Y1175 tyrosine phosphorylation in vascular endothelial growth factor receptor 2 (VEGFR2) through receptor tyrosine kinase-like orphan receptor 2 (ROR2), a Wnt-specific receptor. We found that ROR2 knockdown mimics Wnt7a insufficiency and prevents recovery of tip cell formation with Wnt7a stimulation. While there was no difference between wild-type and endothelial-specific Wnt7a -/- mice under either chronic hypoxia or SuHx, global Wnt7a +/- mice in hypoxia demonstrated higher pulmonary pressures and severe right ventricular and lung vascular remodelling. Similar to PAH, Wnt7a +/- PMVECs exhibited an insufficient angiogenic response to VEGF-A that improved with Wnt7a. CONCLUSIONS Wnt7a promotes VEGF signalling in lung PMVECs and its loss is associated with an insufficient VEGF-A angiogenic response. We propose that Wnt7a deficiency contributes to progressive small vessel loss in PAH.
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Affiliation(s)
- Ananya Chakraborty
- Division of Pulmonary and Critical Care, Stanford University, Palo Alto, CA, USA
- These authors contributed equally
| | - Abinaya Nathan
- Division of Pulmonary and Critical Care, Stanford University, Palo Alto, CA, USA
- These authors contributed equally
| | - Mark Orcholski
- Department of Medicine, University of Laval, Quebec City, QC, Canada
| | - Stuti Agarwal
- Division of Pulmonary and Critical Care, Stanford University, Palo Alto, CA, USA
| | | | - Natasha Auer
- Division of Pulmonary and Critical Care, Stanford University, Palo Alto, CA, USA
| | - Ankita Mitra
- Division of Pulmonary and Critical Care, Stanford University, Palo Alto, CA, USA
| | | | - Gowri Swaminathan
- Division of Pulmonary and Critical Care, Stanford University, Palo Alto, CA, USA
| | - David F Condon
- Division of Pulmonary and Critical Care, Stanford University, Palo Alto, CA, USA
| | - Joyce Yu
- Division of Pulmonary and Critical Care, Stanford University, Palo Alto, CA, USA
| | - Matthew McCarra
- Division of Pulmonary and Critical Care, Stanford University, Palo Alto, CA, USA
| | - Nicholas H Juul
- Division of Pulmonary and Critical Care, Stanford University, Palo Alto, CA, USA
| | | | | | - Ke Yuan
- Boston Children's Hospital, Boston, MA, USA
| | | | - Joseph T Crossno
- Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | | | - Paul B Yu
- Brigham and Women's Hospital, Boston, MA, USA
| | | | - Robert A Winn
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
| | | | | | - Tim Lahm
- National Jewish Center, Denver, CO, USA
| | - Haley Hedlin
- Division of Pulmonary and Critical Care, Stanford University, Palo Alto, CA, USA
| | - Jeffrey R Fineman
- Department of Pediatrics and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Robert Lafyatis
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Carsten N F Knutsen
- Division of Pediatric Critical Care Medicine, Stanford University, Palo Alto, CA, USA
| | - Cristina M Alvira
- Division of Pediatric Critical Care Medicine, Stanford University, Palo Alto, CA, USA
| | - David N Cornfield
- Division of Pediatric Pulmonary and Critical Care Medicine, Stanford University, Palo Alto, CA, USA
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3
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Lorenzen L, Frank D, Schwan C, Grosse R. Spatiotemporal Regulation of FMNL2 by N-Terminal Myristoylation and C-Terminal Phosphorylation Drives Rapid Filopodia Formation. Biomolecules 2023; 13:biom13030548. [PMID: 36979484 PMCID: PMC10046779 DOI: 10.3390/biom13030548] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/10/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
The actin nucleating and polymerizing formin-like 2 (FMNL2) is upregulated in several cancers and has been shown to play important roles in cell migration, invasion, cell–cell adhesion and filopodia formation. Here, using structured illumination microscopy we show that FMNL2 promotes rapid and highly dynamic filopodia formation in epithelial cells while remaining on the tip of the growing filopodia. This filopodia tip localization depends fully on its N-terminal myristoylation. We further show that FMNL2-dependent filopodia formation requires its serine 1072 phosphorylation within the diaphanous-autoregulatory domain (DAD) by protein kinase C (PKC) α. Consistent with this, filopodia formation depends on PKC activity and PKCα localizes to the base of growing filopodia. Thus, a PKCα–FMNL2 signaling module spatiotemporally controls dynamic filopodia formation.
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Affiliation(s)
- Lina Lorenzen
- Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty, University of Freiburg, 79104 Freiburg, Germany
| | - Dennis Frank
- Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty, University of Freiburg, 79104 Freiburg, Germany
| | - Carsten Schwan
- Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty, University of Freiburg, 79104 Freiburg, Germany
- Correspondence: (C.S.); (R.G.)
| | - Robert Grosse
- Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty, University of Freiburg, 79104 Freiburg, Germany
- Centre for Integrative Biological Signalling Studies—CIBSS, 79104 Freiburg, Germany
- Correspondence: (C.S.); (R.G.)
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4
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Hein JI, Scholz J, Körber S, Kaufmann T, Faix J. Unleashed Actin Assembly in Capping Protein-Deficient B16-F1 Cells Enables Identification of Multiple Factors Contributing to Filopodium Formation. Cells 2023; 12:cells12060890. [PMID: 36980231 PMCID: PMC10047565 DOI: 10.3390/cells12060890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/16/2023] Open
Abstract
Background: Filopodia are dynamic, finger-like actin-filament bundles that overcome membrane tension by forces generated through actin polymerization at their tips to allow extension of these structures a few microns beyond the cell periphery. Actin assembly of these protrusions is regulated by accessory proteins including heterodimeric capping protein (CP) or Ena/VASP actin polymerases to either terminate or promote filament growth. Accordingly, the depletion of CP in B16-F1 melanoma cells was previously shown to cause an explosive formation of filopodia. In Ena/VASP-deficient cells, CP depletion appeared to result in ruffling instead of inducing filopodia, implying that Ena/VASP proteins are absolutely essential for filopodia formation. However, this hypothesis was not yet experimentally confirmed. Methods: Here, we used B16-F1 cells and CRISPR/Cas9 technology to eliminate CP either alone or in combination with Ena/VASP or other factors residing at filopodia tips, followed by quantifications of filopodia length and number. Results: Unexpectedly, we find massive formations of filopodia even in the absence of CP and Ena/VASP proteins. Notably, combined inactivation of Ena/VASP, unconventional myosin-X and the formin FMNL3 was required to markedly impair filopodia formation in CP-deficient cells. Conclusions: Taken together, our results reveal that, besides Ena/VASP proteins, numerous other factors contribute to filopodia formation.
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Affiliation(s)
| | | | | | | | - Jan Faix
- Correspondence: ; Tel.: +49-511-532-2928
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5
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Rajan S, Kudryashov DS, Reisler E. Actin Bundles Dynamics and Architecture. Biomolecules 2023; 13:450. [PMID: 36979385 PMCID: PMC10046292 DOI: 10.3390/biom13030450] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/04/2023] Open
Abstract
Cells use the actin cytoskeleton for many of their functions, including their division, adhesion, mechanosensing, endo- and phagocytosis, migration, and invasion. Actin bundles are the main constituent of actin-rich structures involved in these processes. An ever-increasing number of proteins that crosslink actin into bundles or regulate their morphology is being identified in cells. With recent advances in high-resolution microscopy and imaging techniques, the complex process of bundles formation and the multiple forms of physiological bundles are beginning to be better understood. Here, we review the physiochemical and biological properties of four families of highly conserved and abundant actin-bundling proteins, namely, α-actinin, fimbrin/plastin, fascin, and espin. We describe the similarities and differences between these proteins, their role in the formation of physiological actin bundles, and their properties-both related and unrelated to their bundling abilities. We also review some aspects of the general mechanism of actin bundles formation, which are known from the available information on the activity of the key actin partners involved in this process.
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Affiliation(s)
- Sudeepa Rajan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH 43210, USA
| | - Emil Reisler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
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Zheng Y, Wu Z, Hou Y, Li N, Zhang Q, Lin JM. Microfluidic Engineering of Crater-Terrain Hydrogel Microparticles: Toward Novel Cell Carriers. ACS APPLIED MATERIALS & INTERFACES 2023; 15:7833-7840. [PMID: 36630085 DOI: 10.1021/acsami.2c21104] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Fabrication and application of novel anisotropic microparticles are of wide interest. Herein, a new method for producing novel crater-terrain hydrogel microparticles is presented using a concept of droplet-aerosol impact and regional polymerization. The surface pattern of microparticles is similar to the widespread "crater" texture on the lunar surface and can be regulated by the impact morphology of aerosols on the droplet surface. Methodological applicability was demonstrated by producing ionic-cross-linked (alginate) and photo-cross-linked (poly(ethylene glycol) diacrylate, PEGDA) microparticles. Additionally, the crater-terrain microparticles (CTMs) can induce nonspecific protein absorption on their surface to acquire cell affinity, and they were exploited as cell carriers to load living cells. Cells could adhere and proliferate, and a special cellular adhesion fingerprint was observed on the novel cell carrier. Therefore, the scalable manufacturing method and biological potential make the engineered microparticles promising to open a new avenue for exploring cell-biomaterial crosstalk.
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Affiliation(s)
- Yajing Zheng
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Tsinghua University, Beijing 100084, China
| | - Zengnan Wu
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Tsinghua University, Beijing 100084, China
| | - Ying Hou
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Tsinghua University, Beijing 100084, China
| | - Nan Li
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Tsinghua University, Beijing 100084, China
| | - Qiang Zhang
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Tsinghua University, Beijing 100084, China
| | - Jin-Ming Lin
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Tsinghua University, Beijing 100084, China
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7
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Liu L, Sui R, Li L, Zhang L, Zeng D, Ni X, Sun J. Light Activates Cdc42-Mediated Needle-Shaped Filopodia Formation via the Integration of Small GTPases. Cell Mol Bioeng 2022; 15:599-609. [PMID: 36531863 PMCID: PMC9751244 DOI: 10.1007/s12195-022-00743-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 09/28/2022] [Indexed: 11/28/2022] Open
Abstract
Introduction Cdc42 has been linked to multiple human cancers and is implicated in the migration of cancer cells. Cdc42 could be activated via biochemical and biophysical factors in tumor microenvironment, the precise control of Cdc42 was essential to determine its role to cell behaviors. Needle-shaped protrusions (filopodia) could sense the extracellular biochemical cues and pave the path for cell movement, which was a key structure involved in the regulation of cancer cell motility. Methods We used the photoactivatable Cdc42 to elucidate the breast cancer cell protrusions, the mutation of Cdc42 was to confirm the optogenetic results. We also inhibit the Cdc42, Rac or Rho respectively by the corresponding inhibitors. Results We identified that the activation of Cdc42 by light could greatly enhance the formation of filopodia, which was positive for the contribution of cell movement. The expression of Cdc42 active form Cdc42-Q61L in cells resulted in the longer and more filopodia while the Cdc42 inactive form Cdc42-T17N were with the shorter and less filopodia. Moreover, the inhibition of Cdc42, Rac or Rho all significantly reduced the filopodia numbers and length in the co-expression of Cdc42-Q61L, which showed that the integration of small GTPases was necessary in the formation of filopodia. Furthermore, photoactivation of Cdc42 failed to enhance the filopodia formation with the inhibition of Rac or Rho. However, with the inhibition of Cdc42, the photoactivation of Cdc42 could partially recover back the filopodia formations, which indicated that the integration of small GTPases was key for the filopodia formations. Conclusions Our work highlights that light activates Cdc42 is sufficient to promote filopodia formation without the destructive structures of small GTPases, it not only points out the novel technique to determine cell structure formations but also provides the experimental basis for the efficient small GTPases-based anti-cancer strategies.
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Affiliation(s)
- Lingling Liu
- School of Medical Laboratory Science, Chengdu Medical College, Chengdu, 610500 Sichuan China
| | - Ran Sui
- Animal Microecology Institute, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
| | - Lianxin Li
- Animal Microecology Institute, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
| | - Lin Zhang
- School of Medical Laboratory Science, Chengdu Medical College, Chengdu, 610500 Sichuan China
| | - Dong Zeng
- Animal Microecology Institute, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
| | - Xueqin Ni
- Animal Microecology Institute, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
| | - Jinghui Sun
- School of Medical Laboratory Science, Chengdu Medical College, Chengdu, 610500 Sichuan China
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8
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Clarke HJ. Transzonal projections: Essential structures mediating intercellular communication in the mammalian ovarian follicle. Mol Reprod Dev 2022; 89:509-525. [PMID: 36112806 DOI: 10.1002/mrd.23645] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/22/2022] [Accepted: 08/31/2022] [Indexed: 12/25/2022]
Abstract
The development of germ cells relies on contact and communication with neighboring somatic cells that provide metabolic support and regulatory signals. In females, contact is achieved through thin cytoplasmic processes that project from follicle cells surrounding the oocyte, extend through an extracellular matrix (ECM) that lies between them, and reach its surface. In mammals, the ECM is termed the zona pellucida and the follicular cell processes are termed transzonal projections (TZPs). TZPs become detectable when the zona pellucida is laid down during early folliculogenesis and subsequently increase in number as oocyte growth progresses. They then rapidly disappear at the time of ovulation, permanently breaking germ-soma contact. Here we review the life cycle and functions of the TZPs. We begin with an overview of the morphology and cytoskeletal structure of TZPs, in the context of actin- and tubulin-based cytoplasmic processes in other cell types. Next, we review the roles played by TZPs in mediating progression through successive stages of oocyte development. We then discuss two mechanisms that may generate TZPs-stretching at pre-existing points of granulosa cell-oocyte contact and elaboration of new processes that push through the zona pellucida-as well as gene products implicated in their formation or function. Finally, we describe the signaling pathways that cause TZPs to be retracted in response to signals that also trigger meiotic maturation and ovulation of the oocyte. The principles and mechanisms that govern TZP behavior may be relevant to understanding communication between physically separated cells in other physiological contexts.
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Affiliation(s)
- Hugh J Clarke
- Program in Child Health and Human Development, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada.,Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada
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9
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Tsai FC, Henderson JM, Jarin Z, Kremneva E, Senju Y, Pernier J, Mikhajlov O, Manzi J, Kogan K, Le Clainche C, Voth GA, Lappalainen P, Bassereau P. Activated I-BAR IRSp53 clustering controls the formation of VASP-actin-based membrane protrusions. SCIENCE ADVANCES 2022; 8:eabp8677. [PMID: 36240267 PMCID: PMC9565809 DOI: 10.1126/sciadv.abp8677] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Filopodia are actin-rich membrane protrusions essential for cell morphogenesis, motility, and cancer invasion. How cells control filopodium initiation on the plasma membrane remains elusive. We performed experiments in cellulo, in vitro, and in silico to unravel the mechanism of filopodium initiation driven by the membrane curvature sensor IRSp53 (insulin receptor substrate protein of 53 kDa). We showed that full-length IRSp53 self-assembles into clusters on membranes depending on PIP2. Using well-controlled in vitro reconstitution systems, we demonstrated that IRSp53 clusters recruit the actin polymerase VASP (vasodilator-stimulated phosphoprotein) to assemble actin filaments locally on membranes, leading to the generation of actin-filled membrane protrusions reminiscent of filopodia. By pulling membrane nanotubes from live cells, we observed that IRSp53 can only be enriched and trigger actin assembly in nanotubes at highly dynamic membrane regions. Our work supports a regulation mechanism of IRSp53 in its attributes of curvature sensation and partner recruitment to ensure a precise spatial-temporal control of filopodium initiation.
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Affiliation(s)
- Feng-Ching Tsai
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
- Corresponding author. (F.-C.T.); (G.A.V.); (P.L.); (P.B.)
| | - J. Michael Henderson
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
- Unité de Trafic Membranaire et Pathogénèse, Département de Biologie Cellulaire et Infection, Institut Pasteur, Université de Paris, CNRS UMR 3691, 75015 Paris, France
| | - Zack Jarin
- Pritzker School for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Elena Kremneva
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Yosuke Senju
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama, Japan
| | - Julien Pernier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Oleg Mikhajlov
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - John Manzi
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - Konstantin Kogan
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Christophe Le Clainche
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Gregory A. Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA
- Corresponding author. (F.-C.T.); (G.A.V.); (P.L.); (P.B.)
| | - Pekka Lappalainen
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
- Corresponding author. (F.-C.T.); (G.A.V.); (P.L.); (P.B.)
| | - Patricia Bassereau
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
- Corresponding author. (F.-C.T.); (G.A.V.); (P.L.); (P.B.)
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10
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Tsai FC, Henderson JM, Jarin Z, Kremneva E, Senju Y, Pernier J, Mikhajlov O, Manzi J, Kogan K, Le Clainche C, Voth GA, Lappalainen P, Bassereau P. Activated I-BAR IRSp53 clustering controls the formation of VASP-actin-based membrane protrusions. SCIENCE ADVANCES 2022; 8:eabp8677. [PMID: 36240267 DOI: 10.1101/2022.03.04.483020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Filopodia are actin-rich membrane protrusions essential for cell morphogenesis, motility, and cancer invasion. How cells control filopodium initiation on the plasma membrane remains elusive. We performed experiments in cellulo, in vitro, and in silico to unravel the mechanism of filopodium initiation driven by the membrane curvature sensor IRSp53 (insulin receptor substrate protein of 53 kDa). We showed that full-length IRSp53 self-assembles into clusters on membranes depending on PIP2. Using well-controlled in vitro reconstitution systems, we demonstrated that IRSp53 clusters recruit the actin polymerase VASP (vasodilator-stimulated phosphoprotein) to assemble actin filaments locally on membranes, leading to the generation of actin-filled membrane protrusions reminiscent of filopodia. By pulling membrane nanotubes from live cells, we observed that IRSp53 can only be enriched and trigger actin assembly in nanotubes at highly dynamic membrane regions. Our work supports a regulation mechanism of IRSp53 in its attributes of curvature sensation and partner recruitment to ensure a precise spatial-temporal control of filopodium initiation.
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Affiliation(s)
- Feng-Ching Tsai
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - J Michael Henderson
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
- Unité de Trafic Membranaire et Pathogénèse, Département de Biologie Cellulaire et Infection, Institut Pasteur, Université de Paris, CNRS UMR 3691, 75015 Paris, France
| | - Zack Jarin
- Pritzker School for Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Elena Kremneva
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Yosuke Senju
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama, Japan
| | - Julien Pernier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Oleg Mikhajlov
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - John Manzi
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - Konstantin Kogan
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Christophe Le Clainche
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA
| | - Pekka Lappalainen
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Patricia Bassereau
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
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11
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Nast-Kolb T, Bleicher P, Payr M, Bausch AR. VASP localization to lipid bilayers induces polymerization driven actin bundle formation. Mol Biol Cell 2022; 33:ar91. [PMID: 35830600 PMCID: PMC9582628 DOI: 10.1091/mbc.e21-11-0577] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Actin bundles constitute important cytoskeleton structures and enable a scaffold for force transmission inside cells. Actin bundles are formed by proteins, with multiple F-actin binding domains cross-linking actin filaments to each other. Vasodilator-stimulated phosphoprotein (VASP) has mostly been reported as an actin elongator, but it has been shown to be a bundling protein as well and is found in bundled actin structures at filopodia and adhesion sites. Based on in vitro experiments, it remains unclear when and how VASP can act as an actin bundler or elongator. Here we demonstrate that VASP bound to membranes facilitates the formation of large actin bundles during polymerization. The alignment by polymerization requires the fluidity of the lipid bilayers. The mobility within the bilayer enables VASP to bind to filaments and capture and track growing barbed ends. VASP itself phase separates into a protein-enriched phase on the bilayer. This VASP-rich phase nucleates and accumulates at bundles during polymerization, which in turn leads to a reorganization of the underlying lipid bilayer. Our findings demonstrate that the nature of VASP localization is decisive for its function. The up-concentration based on VASP’s affinity to actin during polymerization enables it to simultaneously fulfill the function of an elongator and a bundler.
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Affiliation(s)
- T Nast-Kolb
- Lehrstuhl für Biophysik E27, Physik-Department, Technische Universität München, Garching, Germany and
| | - P Bleicher
- Lehrstuhl für Biophysik E27, Physik-Department, Technische Universität München, Garching, Germany and.,Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892
| | - M Payr
- Lehrstuhl für Biophysik E27, Physik-Department, Technische Universität München, Garching, Germany and.,Structural and Computational Biology Unit, EMBL Heidelberg, Meyerhoferstr. 1, 69117 Heidelberg, Germany
| | - A R Bausch
- Center for Protein Assemblies (CPA), Ernst-Otto-Fischer Str. 8, 85747 Garching, Germany
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12
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Heckman CA, Ademuyiwa OM, Cayer ML. How filopodia respond to calcium in the absence of a calcium-binding structural protein: non-channel functions of TRP. Cell Commun Signal 2022; 20:130. [PMID: 36028898 PMCID: PMC9414478 DOI: 10.1186/s12964-022-00927-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 06/21/2022] [Indexed: 11/18/2022] Open
Abstract
Background For many cell types, directional locomotion depends on their maintaining filopodia at the leading edge. Filopodia lack any Ca2+-binding structural protein but respond to store-operated Ca2+ entry (SOCE). Methods SOCE was induced by first replacing the medium with Ca2+-free salt solution with cyclopiazonic acid (CPA). This lowers Ca2+ in the ER and causes stromal interacting molecule (STIM) to be translocated to the cell surface. After this priming step, CPA was washed out, and Ca2+ influx restored by addition of extracellular Ca2+. Intracellular Ca2+ levels were measured by calcium orange fluorescence. Regulatory mechanisms were identified by pharmacological treatments. Proteins mediating SOCE were localized by immunofluorescence and analyzed after image processing. Results Depletion of the ER Ca2+ increased filopodia prevalence briefly, followed by a spontaneous decline that was blocked by inhibitors of endocytosis. Intracellular Ca2+ increased continuously for ~ 50 min. STIM and a transient receptor potential canonical (TRPC) protein were found in separate compartments, but an aquaporin unrelated to SOCE was present in both. STIM1- and TRPC1-bearing vesicles were trafficked on microtubules. During depletion, STIM1 migrated to the surface where it coincided with Orai in punctae, as expected. TRPC1 was partially colocalized with Vamp2, a rapidly releasable pool marker, and with phospholipases (PLCs). TRPC1 retreated to internal compartments during ER depletion. Replenishment of extracellular Ca2+ altered the STIM1 distribution, which came to resemble that of untreated cells. Vamp2 and TRPC1 underwent exocytosis and became homogeneously distributed on the cell surface. This was accompanied by an increased prevalence of filopodia, which was blocked by inhibitors of TRPC1/4/5 and endocytosis. Conclusions Because the media were devoid of ligands that activate receptors during depletion and Ca2+ replenishment, we could attribute filopodia extension to SOCE. We propose that the Orai current stimulates exocytosis of TRPC-bearing vesicles, and that Ca2+ influx through TRPC inhibits PLC activity. This allows regeneration of the substrate, phosphatidylinositol 4,5 bisphosphate (PIP2), a platform for assembling proteins, e. g. Enabled and IRSp53. TRPC contact with PLC is required but is broken by TRPC dissemination. This explains how STIM1 regulates the cell’s ability to orient itself in response to attractive or repulsive cues. Video Abstract
Supplementary Information The online version contains supplementary material available at 10.1186/s12964-022-00927-y.
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Affiliation(s)
- C A Heckman
- Department of Biological Sciences, 217 Life Science Building, Bowling Green State University, Bowling Green, OH, 43403-0001, USA.
| | - O M Ademuyiwa
- Department of Biological Sciences, 217 Life Science Building, Bowling Green State University, Bowling Green, OH, 43403-0001, USA
| | - M L Cayer
- Center for Microscopy and Microanalysis, Bowling Green State University, Bowling Green, OH, 43403, USA
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13
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Application of piconewton forces to individual filopodia reveals mechanosensory role of L-type Ca 2+ channels. Biomaterials 2022; 284:121477. [PMID: 35395455 DOI: 10.1016/j.biomaterials.2022.121477] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 03/18/2022] [Indexed: 11/02/2022]
Abstract
Filopodia are ubiquitous membrane projections that play crucial role in guiding cell migration on rigid substrates and through extracellular matrix by utilizing yet unknown mechanosensing molecular pathways. As recent studies show that Ca2+ channels localized to filopodia play an important role in regulation of their formation and since some Ca2+ channels are known to be mechanosensitive, force-dependent activity of filopodial Ca2+ channels might be linked to filopodia's mechanosensing function. We tested this hypothesis by monitoring changes in the intra-filopodial Ca2+ level in response to application of stretching force to individual filopodia of several cell types using optical tweezers. Results show that stretching forces of tens of pN strongly promote Ca2+ influx into filopodia, causing persistent Ca2+ oscillations that last for minutes even after the force is released. Several known mechanosensitive Ca2+ channels, such as Piezo 1, Piezo 2 and TRPV4, were found to be dispensable for the observed force-dependent Ca2+ influx, while L-type Ca2+ channels appear to be a key player in the discovered phenomenon. As previous studies have shown that intra-filopodial transient Ca2+ signals play an important role in guidance of cell migration, our results suggest that the force-dependent activation of L-type Ca2+ channels may contribute to this process. Overall, our study reveals an intricate interplay between mechanical forces and Ca2+ signaling in filopodia, providing novel mechanistic insights for the force-dependent filopodia functions in guidance of cell migration.
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14
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Arthur AL, Crawford A, Houdusse A, Titus MA. VASP-mediated actin dynamics activate and recruit a filopodia myosin. eLife 2021; 10:68082. [PMID: 34042588 PMCID: PMC8352590 DOI: 10.7554/elife.68082] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/20/2021] [Indexed: 11/17/2022] Open
Abstract
Filopodia are thin, actin-based structures that cells use to interact with their environments. Filopodia initiation requires a suite of conserved proteins but the mechanism remains poorly understood. The actin polymerase VASP and a MyTH-FERM (MF) myosin, DdMyo7 in amoeba, are essential for filopodia initiation. DdMyo7 is localized to dynamic regions of the actin-rich cortex. Analysis of VASP mutants and treatment of cells with anti-actin drugs shows that myosin recruitment and activation in Dictyostelium requires localized VASP-dependent actin polymerization. Targeting of DdMyo7 to the cortex alone is not sufficient for filopodia initiation; VASP activity is also required. The actin regulator locally produces a cortical actin network that activates myosin and together they shape the actin network to promote extension of parallel bundles of actin during filopodia formation. This work reveals how filopodia initiation requires close collaboration between an actin-binding protein, the state of the actin cytoskeleton and MF myosin activity.
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Affiliation(s)
- Ashley L Arthur
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
| | - Amy Crawford
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
| | - Anne Houdusse
- Structural Motility, Institut Curie, Paris Université Sciences et Lettres, Sorbonne Université, Paris, France
| | - Margaret A Titus
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
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15
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Dobramysl U, Jarsch IK, Inoue Y, Shimo H, Richier B, Gadsby JR, Mason J, Szałapak A, Ioannou PS, Correia GP, Walrant A, Butler R, Hannezo E, Simons BD, Gallop JL. Stochastic combinations of actin regulatory proteins are sufficient to drive filopodia formation. J Cell Biol 2021; 220:e202003052. [PMID: 33740033 PMCID: PMC7980258 DOI: 10.1083/jcb.202003052] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 11/23/2020] [Accepted: 01/12/2021] [Indexed: 11/22/2022] Open
Abstract
Assemblies of actin and its regulators underlie the dynamic morphology of all eukaryotic cells. To understand how actin regulatory proteins work together to generate actin-rich structures such as filopodia, we analyzed the localization of diverse actin regulators within filopodia in Drosophila embryos and in a complementary in vitro system of filopodia-like structures (FLSs). We found that the composition of the regulatory protein complex where actin is incorporated (the filopodial tip complex) is remarkably heterogeneous both in vivo and in vitro. Our data reveal that different pairs of proteins correlate with each other and with actin bundle length, suggesting the presence of functional subcomplexes. This is consistent with a theoretical framework where three or more redundant subcomplexes join the tip complex stochastically, with any two being sufficient to drive filopodia formation. We provide an explanation for the observed heterogeneity and suggest that a mechanism based on multiple components allows stereotypical filopodial dynamics to arise from diverse upstream signaling pathways.
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Affiliation(s)
- Ulrich Dobramysl
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Iris Katharina Jarsch
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Yoshiko Inoue
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Hanae Shimo
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Benjamin Richier
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Jonathan R. Gadsby
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Julia Mason
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Alicja Szałapak
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Pantelis Savvas Ioannou
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | - Astrid Walrant
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Richard Butler
- Gurdon Institute, University of Cambridge, Cambridge, UK
| | - Edouard Hannezo
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Benjamin D. Simons
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK
| | - Jennifer L. Gallop
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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16
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Jarsch IK, Gadsby JR, Nuccitelli A, Mason J, Shimo H, Pilloux L, Marzook B, Mulvey CM, Dobramysl U, Bradshaw CR, Lilley KS, Hayward RD, Vaughan TJ, Dobson CL, Gallop JL. A direct role for SNX9 in the biogenesis of filopodia. J Cell Biol 2020; 219:151579. [PMID: 32328641 PMCID: PMC7147113 DOI: 10.1083/jcb.201909178] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/24/2020] [Accepted: 01/31/2020] [Indexed: 12/13/2022] Open
Abstract
Filopodia are finger-like actin-rich protrusions that extend from the cell surface and are important for cell-cell communication and pathogen internalization. The small size and transient nature of filopodia combined with shared usage of actin regulators within cells confounds attempts to identify filopodial proteins. Here, we used phage display phenotypic screening to isolate antibodies that alter the actin morphology of filopodia-like structures (FLS) in vitro. We found that all of the antibodies that cause shorter FLS interact with SNX9, an actin regulator that binds phosphoinositides during endocytosis and at invadopodia. In cells, we discover SNX9 at specialized filopodia in Xenopus development and that SNX9 is an endogenous component of filopodia that are hijacked by Chlamydia entry. We show the use of antibody technology to identify proteins used in filopodia-like structures, and a role for SNX9 in filopodia.
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Affiliation(s)
- Iris K Jarsch
- Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Jonathan R Gadsby
- Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Annalisa Nuccitelli
- Antibody Discovery and Protein Engineering, AstraZeneca, Granta Park, Cambridge, UK
| | - Julia Mason
- Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Hanae Shimo
- Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Ludovic Pilloux
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Bishara Marzook
- Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Claire M Mulvey
- Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Ulrich Dobramysl
- Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Charles R Bradshaw
- Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Kathryn S Lilley
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | - Tristan J Vaughan
- Antibody Discovery and Protein Engineering, AstraZeneca, Granta Park, Cambridge, UK
| | - Claire L Dobson
- Antibody Discovery and Protein Engineering, AstraZeneca, Granta Park, Cambridge, UK
| | - Jennifer L Gallop
- Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge, UK
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17
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Gallop J. Filopodia and their links with membrane traffic and cell adhesion. Semin Cell Dev Biol 2020; 102:81-89. [DOI: 10.1016/j.semcdb.2019.11.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 11/14/2019] [Accepted: 11/28/2019] [Indexed: 01/24/2023]
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18
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Christie SM, Ham TR, Gilmore GT, Toth PD, Leipzig ND, Smith AW. Covalently Immobilizing Interferon-γ Drives Filopodia Production through Specific Receptor-Ligand Interactions Independently of Canonical Downstream Signaling. Bioconjug Chem 2020; 31:1362-1369. [PMID: 32329609 PMCID: PMC10243121 DOI: 10.1021/acs.bioconjchem.0c00105] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Immobilizing a signaling protein to guide cell behavior has been employed in a wide variety of studies. This approach draws inspiration from biology, where specific, affinity-based interactions between membrane receptors and immobilized proteins in the extracellular matrix guide many developmental and homeostatic processes. Synthetic immobilization approaches, however, do not necessarily recapitulate the in vivo signaling system and potentially lead to artificial receptor-ligand interactions. To investigate the effects of one example of engineered receptor-ligand interactions, we focus on the immobilization of interferon-γ (IFN-γ), which has been used to drive differentiation of neural stem cells (NSCs). To isolate the effect of ligand immobilization, we transfected Cos-7 cells with only interferon-γ receptor 1 (IFNγR1), not IFNγR2, so that the cells could bind IFN-γ but were incapable of canonical signal transduction. We then exposed the cells to surfaces containing covalently immobilized IFN-γ and studied membrane morphology, receptor-ligand dynamics, and receptor activation. We found that exposing cells to immobilized but not soluble IFN-γ drove the formation of filopodia in both NSCs and Cos-7, showing that covalently immobilizing IFN-γ is enough to affect cell behavior, independently of canonical downstream signaling. Overall, this work suggests that synthetic growth factor immobilization can influence cell morphology beyond enhancing canonical cell responses through the prolonged signaling duration or spatial patterning enabled by protein immobilization. This suggests that differentiation of NSCs could be driven by canonical and non-canonical pathways when IFN-γ is covalently immobilized. This finding has broad implications for bioengineering approaches to guide cell behavior, as one ligand has the potential to impact multiple pathways even when cells lack the canonical signal transduction machinery.
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Affiliation(s)
- Shaun M. Christie
- Department of Chemistry, The University of Akron, 190 Buchtel Common, Akron, Ohio, 44325, United States
| | - Trevor R. Ham
- Department of Biomedical Engineering, The University of Akron, Auburn Science and Engineering Center #275, West Tower, Akron, OH 44325, United States
| | - Grant T. Gilmore
- Department of Chemistry, The University of Akron, 190 Buchtel Common, Akron, Ohio, 44325, United States
| | - Paul D. Toth
- Department of Chemistry, The University of Akron, 190 Buchtel Common, Akron, Ohio, 44325, United States
| | - Nic D. Leipzig
- Department of Biomedical Engineering, The University of Akron, Auburn Science and Engineering Center #275, West Tower, Akron, OH 44325, United States
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, 302 Buchtel Common, Akron, Ohio, 44325, United States
| | - Adam W. Smith
- Department of Chemistry, The University of Akron, 190 Buchtel Common, Akron, Ohio, 44325, United States
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19
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Damiano-Guercio J, Kurzawa L, Mueller J, Dimchev G, Schaks M, Nemethova M, Pokrant T, Brühmann S, Linkner J, Blanchoin L, Sixt M, Rottner K, Faix J. Loss of Ena/VASP interferes with lamellipodium architecture, motility and integrin-dependent adhesion. eLife 2020; 9:55351. [PMID: 32391788 PMCID: PMC7239657 DOI: 10.7554/elife.55351] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 05/08/2020] [Indexed: 01/21/2023] Open
Abstract
Cell migration entails networks and bundles of actin filaments termed lamellipodia and microspikes or filopodia, respectively, as well as focal adhesions, all of which recruit Ena/VASP family members hitherto thought to antagonize efficient cell motility. However, we find these proteins to act as positive regulators of migration in different murine cell lines. CRISPR/Cas9-mediated loss of Ena/VASP proteins reduced lamellipodial actin assembly and perturbed lamellipodial architecture, as evidenced by changed network geometry as well as reduction of filament length and number that was accompanied by abnormal Arp2/3 complex and heterodimeric capping protein accumulation. Loss of Ena/VASP function also abolished the formation of microspikes normally embedded in lamellipodia, but not of filopodia capable of emanating without lamellipodia. Ena/VASP-deficiency also impaired integrin-mediated adhesion accompanied by reduced traction forces exerted through these structures. Our data thus uncover novel Ena/VASP functions of these actin polymerases that are fully consistent with their promotion of cell migration.
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Affiliation(s)
| | - Laëtitia Kurzawa
- CytoMorphoLab, Laboratoire de Physiologie cellulaire et Végétale, Interdisciplinary ResearchInstitute of Grenoble, CEA, CNRS, INRA, Grenoble-Alpes University, Grenoble, France.,CytomorphoLab, Hôpital Saint-Louis, Institut Universitaire d'Hematologie, UMRS1160, INSERM/AP-HP/UniversitéParis Diderot, Paris, France
| | - Jan Mueller
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Georgi Dimchev
- Division of Molecular Cell Biology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany
| | - Matthias Schaks
- Division of Molecular Cell Biology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Maria Nemethova
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Thomas Pokrant
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Stefan Brühmann
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Joern Linkner
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Laurent Blanchoin
- CytoMorphoLab, Laboratoire de Physiologie cellulaire et Végétale, Interdisciplinary ResearchInstitute of Grenoble, CEA, CNRS, INRA, Grenoble-Alpes University, Grenoble, France.,CytomorphoLab, Hôpital Saint-Louis, Institut Universitaire d'Hematologie, UMRS1160, INSERM/AP-HP/UniversitéParis Diderot, Paris, France
| | - Michael Sixt
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
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20
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A Cdc42-mediated supracellular network drives polarized forces and Drosophila egg chamber extension. Nat Commun 2020; 11:1921. [PMID: 32317641 PMCID: PMC7174421 DOI: 10.1038/s41467-020-15593-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 03/13/2020] [Indexed: 01/09/2023] Open
Abstract
Actomyosin supracellular networks emerge during development and tissue repair. These cytoskeletal structures are able to generate large scale forces that can extensively remodel epithelia driving tissue buckling, closure and extension. How supracellular networks emerge, are controlled and mechanically work still remain elusive. During Drosophila oogenesis, the egg chamber elongates along the anterior-posterior axis. Here we show that a dorsal-ventral polarized supracellular F-actin network, running around the egg chamber on the basal side of follicle cells, emerges from polarized intercellular filopodia that radiate from basal stress fibers and extend penetrating neighboring cell cortexes. Filopodia can be mechanosensitive and function as cell-cell anchoring sites. The small GTPase Cdc42 governs the formation and distribution of intercellular filopodia and stress fibers in follicle cells. Finally, our study shows that a Cdc42-dependent supracellular cytoskeletal network provides a scaffold integrating local oscillatory actomyosin contractions at the tissue scale to drive global polarized forces and tissue elongation. During development, organs undergo large scale forces driven by the cytoskeleton but the precise molecular regulation of cytoskeletal networks remains unclear. Here, the authors report a Cdc42-dependent supracellular cytoskeletal network integrates local actomyosin contraction at tissue scale and drives global tissue elongation.
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21
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Martiel JL, Michelot A, Boujemaa-Paterski R, Blanchoin L, Berro J. Force Production by a Bundle of Growing Actin Filaments Is Limited by Its Mechanical Properties. Biophys J 2019; 118:182-192. [PMID: 31791547 DOI: 10.1016/j.bpj.2019.10.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 10/16/2019] [Accepted: 10/30/2019] [Indexed: 12/16/2022] Open
Abstract
Bundles of actin filaments are central to a large variety of cellular structures such as filopodia, stress fibers, cytokinetic rings, and focal adhesions. The mechanical properties of these bundles are critical for proper force transmission and force bearing. Previous mathematical modeling efforts have focused on bundles' rigidity and shape. However, it remains unknown how bundle length and buckling are controlled by external physical factors. In this work, we present a biophysical model for dynamic bundles of actin filaments submitted to an external load. In combination with in vitro motility assays of beads coated with formins, our model allowed us to characterize conditions for bead movement and bundle buckling. From the deformation profiles, we determined key biophysical properties of tethered actin bundles such as their rigidity and filament density.
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Affiliation(s)
- Jean-Louis Martiel
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France; CNRS, CHU Grenoble-Alpes, Inserm, TIMC-IMAG, University Grenoble-Alpes, Grenoble, France.
| | - Alphée Michelot
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France; CNRS, IBDM, Turing Centre for Living Systems, Aix Marseille University, Marseille, France
| | - Rajaa Boujemaa-Paterski
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France; Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Laurent Blanchoin
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France
| | - Julien Berro
- CytomorphoLab, Biosciences & Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, Université Grenoble-Alpes/CEA/CNRS/INRA, Grenoble, France; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut; Nanobiology Institute, Yale University, West Haven, Connecticut; Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut.
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22
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Liu L, Jiang H, Zhao W, Meng Y, Li J, Huang T, Sun J. Cdc42-mediated supracellular cytoskeleton induced cancer cell migration under low shear stress. Biochem Biophys Res Commun 2019; 519:134-140. [PMID: 31477271 DOI: 10.1016/j.bbrc.2019.08.149] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 08/26/2019] [Indexed: 01/29/2023]
Abstract
Tumor microenvironment is composed of biological, chemical and physical factors. Mechanical factors are more and more focused these years. Therefore, mimicking mechanical factors' contribution to cancer cell malignancy will greatly improve the advance in this field. Although the induced malignant behaviors are present under many stimuli such as growth or inflammatory factors, the cell key physical migration mechanisms are still missing. In this study, we identify that low shear stress significantly promotes the formation of needle-shaped membrane protrusions, which is called filopodia and important for the sense and interact of a cell with extracellular matrix in the tumor microenvironment. Under low shear stress, the migration is promoted while it is inhibited in the presence of ROCK inhibitor Y27632, which could abolish the F-actin network. Using cell imaging, we further unravel that key to these protrusions is Cell division cycle 42 (Cdc42) dependent. After Cdc42 activation, the filopodia is more and longer, acting as massagers to pass the information from a cell to the microenvironment for its malignant phenotype. In the Cdc42 inhibition, the filopodia is greatly reduced. Moreover, small GTPases Cdc42 rather than Rac1 and Rho directly controls the filopodia formation. Our work highlights that low shear stress and Cdc42 activation are sufficient to promote filopodia formation, it not only points out the novel structure for cancer progression but also provides the experimental physical basis for the efficient drug anti-cancer strategies.
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Affiliation(s)
- Lingling Liu
- School of Laboratory Medicine, Collaborative Innovation Center of Sichuan for Elderly Care and Health, Development and Regeneration Key Laboratory of Sichuan Province, Sichuan Provincial Engineering Laboratory for Prevention and Control Technology of Veterinary Drug Residue in Animal-origin Food, Chengdu Medical College, Chengdu, 610500, Sichuan, China
| | - Hua Jiang
- Department of Pediatrics, Department of Microbiology and Immunology, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Wei Zhao
- School of Laboratory Medicine, Collaborative Innovation Center of Sichuan for Elderly Care and Health, Development and Regeneration Key Laboratory of Sichuan Province, Sichuan Provincial Engineering Laboratory for Prevention and Control Technology of Veterinary Drug Residue in Animal-origin Food, Chengdu Medical College, Chengdu, 610500, Sichuan, China
| | - Yao Meng
- School of Laboratory Medicine, Collaborative Innovation Center of Sichuan for Elderly Care and Health, Development and Regeneration Key Laboratory of Sichuan Province, Sichuan Provincial Engineering Laboratory for Prevention and Control Technology of Veterinary Drug Residue in Animal-origin Food, Chengdu Medical College, Chengdu, 610500, Sichuan, China
| | - Ji Li
- Department of Clinical Laboratory, Sichuan GEM Flower Hospital, Chengdu, 610213, Sichuan, PR China
| | - Tongwei Huang
- Department of Blood Transfusion, Ziyang Hospital of Traditional Chinese Medicine, Ziyang, 641300, Sichuan, PR China
| | - Jinghui Sun
- School of Laboratory Medicine, Collaborative Innovation Center of Sichuan for Elderly Care and Health, Development and Regeneration Key Laboratory of Sichuan Province, Sichuan Provincial Engineering Laboratory for Prevention and Control Technology of Veterinary Drug Residue in Animal-origin Food, Chengdu Medical College, Chengdu, 610500, Sichuan, China.
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Hao Y, Yu S, Luo F, Jin LH. Jumu is required for circulating hemocyte differentiation and phagocytosis in Drosophila. Cell Commun Signal 2018; 16:95. [PMID: 30518379 PMCID: PMC6280549 DOI: 10.1186/s12964-018-0305-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 11/19/2018] [Indexed: 11/15/2022] Open
Abstract
Background The regulatory mechanisms of hematopoiesis and cellular immunity show a high degree of similarity between insects and mammals, and Drosophila has become a good model for investigating cellular immune responses. Jumeau (Jumu) is a member of the winged-helix/forkhead (FKH) transcription factor family and is required for Drosophila development. Adult jumu mutant flies show defective hemocyte phagocytosis and a weaker defense capability against pathogen infection. Here, we further investigated the role of jumu in the regulation of larval hemocyte development and phagocytosis. Methods In vivo phagocytosis assays, immunohistochemistry, Real-time quantitative PCR and immunoblotting were performed to investigate the effect of Jumu on hemocyte phagocytosis. 5-Bromo-2-deoxyUridine (BrdU) labeling, phospho-histone H3 (PH3) and TdT-mediated dUTP Nick-End Labeling (TUNEL) staining were performed to analyze the proliferation and apoptosis of hemocyte; immunohistochemistry and Mosaic analysis with a repressible cell marker (MARCM) clone analysis were performed to investigate the role of Jumu in the activation of Toll pathway. Results Jumu indirectly controls hemocyte phagocytosis by regulating the expression of NimC1 and cytoskeleton reorganization. The loss of jumu also causes abnormal proliferation and differentiation in circulating hemocytes. Our results suggest that a severe deficiency of jumu leads to the generation of enlarged multinucleate hemocytes by affecting the normal cell mitosis process and induces numerous lamellocytes by activating the Toll pathway. Conclusions Jumu regulates circulating hemocyte differentiation and phagocytosis in Drosophila. Our findings provide new insight into the mechanistic roles of cytoskeleton regulatory proteins in phagocytosis and establish a basis for further analyses of the regulatory mechanism of the mammalian ortholog of Jumu in mammalian innate immunity. Electronic supplementary material The online version of this article (10.1186/s12964-018-0305-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yangguang Hao
- Department of Genetics, College of Life Sciences, Northeast Forestry University, Harbin, 150040, People's Republic of China.,Department of Translational medicine research center, Shenyang Medical College, Shenyang, 110034, People's Republic of China
| | - Shichao Yu
- Department of Genetics, College of Life Sciences, Northeast Forestry University, Harbin, 150040, People's Republic of China
| | - Fangzhou Luo
- Department of Genetics, College of Life Sciences, Northeast Forestry University, Harbin, 150040, People's Republic of China
| | - Li Hua Jin
- Department of Genetics, College of Life Sciences, Northeast Forestry University, Harbin, 150040, People's Republic of China.
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Young LE, Latario CJ, Higgs HN. Roles for Ena/VASP proteins in FMNL3-mediated filopodial assembly. J Cell Sci 2018; 131:131/21/jcs220814. [PMID: 30373894 DOI: 10.1242/jcs.220814] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 09/25/2018] [Indexed: 02/01/2023] Open
Abstract
Filopodia are actin-dependent finger-like structures that protrude from the plasma membrane. Actin filament barbed-end-binding proteins localized to filopodial tips are key to filopodial assembly. Two classes of barbed-end-binding proteins are formins and Ena/VASP proteins, and both classes have been localized to filopodial tips in specific cellular contexts. Here, we examine the filopodial roles of the FMNL formins and Ena/VASP proteins in U2OS cells. FMNL3 suppression reduces filopodial assembly by 90%, and FMNL3 is enriched at >95% of filopodial tips. Suppression of VASP or Mena (also known as ENAH) reduces filopodial assembly by >75%. However, VASP and Mena do not display consistent filopodial tip localization, but are enriched in focal adhesions (FAs). Interestingly, >85% of FMNL3-containing filopodia are associated with FAs. Two situations increase Ena/VASP filopodial localization: (1) expression of myosin-X, and (2) actively spreading cells. In spreading cells, filopodia often mark sites of nascent adhesions. Interestingly, VASP suppression in spreading cells causes a significant increase in adhesion assembly at filopodial tips. This work demonstrates that, in U2OS cells, Ena/VASP proteins play roles in filopodia beyond those at filopodial tips.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Lorna E Young
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover NH 03755, USA
| | - Casey J Latario
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover NH 03755, USA
| | - Henry N Higgs
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover NH 03755, USA
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25
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Stradal TEB, Schelhaas M. Actin dynamics in host-pathogen interaction. FEBS Lett 2018; 592:3658-3669. [PMID: 29935019 PMCID: PMC6282728 DOI: 10.1002/1873-3468.13173] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 06/19/2018] [Accepted: 06/19/2018] [Indexed: 02/06/2023]
Abstract
The actin cytoskeleton and Rho GTPase signaling to actin assembly are prime targets of bacterial and viral pathogens, simply because actin is involved in all motile and membrane remodeling processes, such as phagocytosis, macropinocytosis, endocytosis, exocytosis, vesicular trafficking and membrane fusion events, motility, and last but not least, autophagy. This article aims at providing an overview of the most prominent pathogen‐induced or ‐hijacked actin structures, and an outlook on how future research might uncover additional, equally sophisticated interactions.
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Affiliation(s)
- Theresia E B Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Mario Schelhaas
- Institute of Cellular Virology, ZMBE, University of Münster, Germany
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26
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Rottner K, Faix J, Bogdan S, Linder S, Kerkhoff E. Actin assembly mechanisms at a glance. J Cell Sci 2018; 130:3427-3435. [PMID: 29032357 DOI: 10.1242/jcs.206433] [Citation(s) in RCA: 185] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The actin cytoskeleton and associated motor proteins provide the driving forces for establishing the astonishing morphological diversity and dynamics of mammalian cells. Aside from functions in protruding and contracting cell membranes for motility, differentiation or cell division, the actin cytoskeleton provides forces to shape and move intracellular membranes of organelles and vesicles. To establish the many different actin assembly functions required in time and space, actin nucleators are targeted to specific subcellular compartments, thereby restricting the generation of specific actin filament structures to those sites. Recent research has revealed that targeting and activation of actin filament nucleators, elongators and myosin motors are tightly coordinated by conserved protein complexes to orchestrate force generation. In this Cell Science at a Glance article and the accompanying poster, we summarize and discuss the current knowledge on the corresponding protein complexes and their modes of action in actin nucleation, elongation and force generation.
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Affiliation(s)
- Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany.,Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Sven Bogdan
- Institute for Physiology and Pathophysiology, Department of Molecular Cell Physiology, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Stefan Linder
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Eppendorf, 20246 Hamburg, Germany
| | - Eugen Kerkhoff
- Department of Neurology, University Hospital Regensburg, 93053 Regensburg, Germany
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27
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Zhang MS, Tran PM, Wolff AJ, Tremblay MM, Fosdick MG, Houtman JCD. Glycerol monolaurate induces filopodia formation by disrupting the association between LAT and SLP-76 microclusters. Sci Signal 2018; 11:11/528/eaam9095. [PMID: 29717064 DOI: 10.1126/scisignal.aam9095] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Glycerol monolaurate (GML) is a monoglyceride with potent antimicrobial properties that suppresses T cell receptor (TCR)-induced signaling and T cell effector function. Actin rearrangement is needed for the interaction of T cells with antigen-presenting cells and for migration to sites of infection. Because of the critical role actin rearrangement plays in T cell effector function, we analyzed the effect of GML on the rearrangement of the actin cytoskeleton after TCR activation. We found that GML-treated human T cells were less adherent than untreated T cells and did not form actin ring structures but instead developed numerous inappropriate actin-mediated filopodia. The formation of these filopodia was not due to disruption of TCR-proximal regulators of actin or microtubule polymerization. Instead, total internal reflection fluorescence microscopy demonstrated mislocalization of actin nucleation protein Arp2 microclusters, but not those containing the adaptor proteins SLP-76 and WASp, or the actin nucleation protein ARPC3, which are necessary for TCR-induced actin rearrangement. Additionally, SLP-76 microclusters colocalized with WASp and WAVE microclusters but not with LAT. Together, our data suggest that GML alters actin cytoskeletal rearrangements and identify diverse functions for GML as a T cell-suppressive agent.
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Affiliation(s)
- Michael S Zhang
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA 52242, USA
| | - Phuong M Tran
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA 52242, USA
| | - Alexander J Wolff
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA 52242, USA
| | - Mikaela M Tremblay
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA 52242, USA
| | - Micaela G Fosdick
- Biomedical Sciences Program, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jon C D Houtman
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA 52242, USA. .,Biomedical Sciences Program, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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A RAB35-p85/PI3K axis controls oscillatory apical protrusions required for efficient chemotactic migration. Nat Commun 2018; 9:1475. [PMID: 29662076 PMCID: PMC5902610 DOI: 10.1038/s41467-018-03571-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 02/15/2018] [Indexed: 11/17/2022] Open
Abstract
How cells move chemotactically remains a major unmet challenge in cell biology. Emerging evidence indicates that for interpreting noisy, shallow gradients of soluble cues a system must behave as an excitable process. Here, through an RNAi-based, high-content screening approach, we identify RAB35 as necessary for the formation of growth factors (GFs)-induced waves of circular dorsal ruffles (CDRs), apically restricted actin-rich migratory protrusions. RAB35 is sufficient to induce recurrent and polarized CDRs that travel as propagating waves, thus behaving as an excitable system that can be biased to control cell steering. Consistently, RAB35 is essential for promoting directed chemotactic migration and chemoinvasion of various cells in response to gradients of motogenic GFs. Molecularly, RAB35 does so by directly regulating the activity of p85/PI3K polarity axis. We propose that RAB35 is a molecular determinant for the control of an excitable, oscillatory system that acts as a steering wheel for GF-mediated chemotaxis and chemoinvasion. Circular dorsal ruffles (CDRs) are apical actin enriched structures involved in the interpretation of growth factor gradients during cell migration. Here, the authors find that a RAB35/PI3K axis is necessary and sufficient for the formation and stabilization of polarized CDRs and persistent directional migration.
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Abstract
The delivery of intracellular material within cells is crucial for maintaining normal function. Myosins transport a wide variety of cargo, ranging from vesicles to ribonuclear protein particles (RNPs), in plants, fungi, and metazoa. The properties of a given myosin transporter are adapted to move on different actin filament tracks, either on the disordered actin networks at the cell cortex or along highly organized actin bundles to distribute their cargo in a localized manner or move it across long distances in the cell. Transport is controlled by selective recruitment of the myosin to its cargo that also plays a role in activation of the motor.
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Affiliation(s)
- Margaret A Titus
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota 55455
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30
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Design of Fiber Networks for Studying Metastatic Invasion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1092:289-318. [DOI: 10.1007/978-3-319-95294-9_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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31
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Clarke HJ. Regulation of germ cell development by intercellular signaling in the mammalian ovarian follicle. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2018; 7:10.1002/wdev.294. [PMID: 28892263 PMCID: PMC5746469 DOI: 10.1002/wdev.294] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 07/21/2017] [Accepted: 08/02/2017] [Indexed: 12/21/2022]
Abstract
Prior to ovulation, the mammalian oocyte undergoes a process of differentiation within the ovarian follicle that confers on it the ability to give rise to an embryo. Differentiation comprises two phases-growth, during which the oocyte increases more than 100-fold in volume as it accumulates macromolecules and organelles that will sustain early embryogenesis; and meiotic maturation, during which the oocyte executes the first meiotic division and prepares for the second division. Entry of an oocyte into the growth phase appears to be triggered when the adjacent granulosa cells produce specific growth factors. As the oocyte grows, it elaborates a thick extracellular coat termed the zona pellucida. Nonetheless, cytoplasmic extensions of the adjacent granulosa cells, termed transzonal projections (TZPs), enable them to maintain contact-dependent communication with the oocyte. Through gap junctions located where the TZP tips meet the oocyte membrane, they provide the oocyte with products that sustain its metabolic activity and signals that regulate its differentiation. Conversely, the oocyte secretes diffusible growth factors that regulate proliferation and differentiation of the granulosa cells. Gap junction-permeable products of the granulosa cells prevent precocious initiation of meiotic maturation, and the gap junctions also enable oocyte maturation to begin in response to hormonal signals received by the granulosa cells. Development of the oocyte or the somatic compartment may also be regulated by extracellular vesicles newly identified in follicular fluid and at TZP tips, which could mediate intercellular transfer of macromolecules. Oocyte differentiation thus depends on continuous signaling interactions with the somatic cells of the follicle. WIREs Dev Biol 2018, 7:e294. doi: 10.1002/wdev.294 This article is categorized under: Gene Expression and Transcriptional Hierarchies > Cellular Differentiation Signaling Pathways > Cell Fate Signaling Early Embryonic Development > Gametogenesis.
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Affiliation(s)
- Hugh J Clarke
- Department of Obstetrics and Gynecology, Research Institute of the McGill University Health Centre, McGill University, Montreal, Canada
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32
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Koons B, Sharma P, Ye Z, Mukherjee A, Lee MH, Wirtz D, Behkam B, Nain AS. Cancer Protrusions on a Tightrope: Nanofiber Curvature Contrast Quantitates Single Protrusion Dynamics. ACS NANO 2017; 11:12037-12048. [PMID: 29144730 DOI: 10.1021/acsnano.7b04567] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Cell migration is studied with the traditional focus on protrusion-driven cell body displacement, while less is known on morphodynamics of individual protrusions themselves, especially in fibrous environments mimicking extracellular matrix. Here, using suspended fibers, we report integrative and multiscale abilities to study protrusive behavior independent of cell body migration. By manipulating the diameter of fibers in orthogonal directions, we constrain cell migration along large diameter (2 μm) base fibers, while solely allowing cells to sense, initiate, and mature protrusions on orthogonally deposited high-curvature/low diameter (∼100, 200, and 600 nm) protrusive fibers and low-curvature (∼300 and 600 nm width) protrusive flat ribbons. In doing so, we report a set of morphodynamic metrics that precisely quantitate protrusion dynamics. Protrusion growth and maturation occur by rapid broadening at the base to achieve long lengths, a behavior dramatically influenced by curvature. While flat ribbons universally induce the formation of broad and long protrusions, we quantitatively protrutype protrusive behavior of two highly invasive cancer cell lines and find breast adenocarcinoma (MDA-MB-231) to exhibit sensitivity to fiber curvature higher than that of brain glioblastoma DBTRG-05MG. Furthermore, while actin and microtubules localize within protrusions of all sizes, we quantify protrusion size-driven localization of vimentin and, contrary to current understanding, report that vimentin is not required to form protrusions. Using multiple protrusive fibers, we quantify high coordination between hierarchical branches of individual protrusions and describe how the spatial configuration of multiple protrusions regulates cell migratory state. Finally, we describe protrusion-driven shedding and collection of cytoplasmic debris.
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Affiliation(s)
| | | | | | | | - Meng Horng Lee
- Engineering in Oncology Center, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Denis Wirtz
- Engineering in Oncology Center, Johns Hopkins University , Baltimore, Maryland 21218, United States
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Dezfuli SN, Huan Z, Mol A, Leeflang S, Chang J, Zhou J. Advanced bredigite-containing magnesium-matrix composites for biodegradable bone implant applications. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017. [DOI: 10.1016/j.msec.2017.05.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Cayuso J, Dzementsei A, Fischer JC, Karemore G, Caviglia S, Bartholdson J, Wright GJ, Ober EA. EphrinB1/EphB3b Coordinate Bidirectional Epithelial-Mesenchymal Interactions Controlling Liver Morphogenesis and Laterality. Dev Cell 2017; 39:316-328. [PMID: 27825440 PMCID: PMC5107609 DOI: 10.1016/j.devcel.2016.10.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 07/24/2016] [Accepted: 10/10/2016] [Indexed: 11/25/2022]
Abstract
Positioning organs in the body often requires the movement of multiple tissues, yet the molecular and cellular mechanisms coordinating such movements are largely unknown. Here, we show that bidirectional signaling between EphrinB1 and EphB3b coordinates the movements of the hepatic endoderm and adjacent lateral plate mesoderm (LPM), resulting in asymmetric positioning of the zebrafish liver. EphrinB1 in hepatoblasts regulates directional migration and mediates interactions with the LPM, where EphB3b controls polarity and movement of the LPM. EphB3b in the LPM concomitantly repels hepatoblasts to move leftward into the liver bud. Cellular protrusions controlled by Eph/Ephrin signaling mediate hepatoblast motility and long-distance cell-cell contacts with the LPM beyond immediate tissue interfaces. Mechanistically, intracellular EphrinB1 domains mediate EphB3b-independent hepatoblast extension formation, while EpB3b interactions cause their destabilization. We propose that bidirectional short- and long-distance cell interactions between epithelial and mesenchyme-like tissues coordinate liver bud formation and laterality via cell repulsion.
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Affiliation(s)
- Jordi Cayuso
- Division of Developmental Biology, Mill Hill Laboratories, The Francis Crick Institute, London NW7 1AA, UK
| | - Aliaksandr Dzementsei
- Danish Stem Cell Center (DanStem), University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Johanna C Fischer
- Division of Developmental Biology, Mill Hill Laboratories, The Francis Crick Institute, London NW7 1AA, UK
| | - Gopal Karemore
- Novo Nordisk Foundation Center for Protein Research, Protein Imaging Platform, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Sara Caviglia
- Danish Stem Cell Center (DanStem), University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Josefin Bartholdson
- Wellcome Trust Sanger Institute, Cell Surface Signalling Laboratory, Cambridge CB10 1HH, UK
| | - Gavin J Wright
- Wellcome Trust Sanger Institute, Cell Surface Signalling Laboratory, Cambridge CB10 1HH, UK
| | - Elke A Ober
- Division of Developmental Biology, Mill Hill Laboratories, The Francis Crick Institute, London NW7 1AA, UK; Danish Stem Cell Center (DanStem), University of Copenhagen, 2200 Copenhagen N, Denmark.
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Steric Effects Induce Geometric Remodeling of Actin Bundles in Filopodia. Biophys J 2017; 110:2066-75. [PMID: 27166814 PMCID: PMC4939473 DOI: 10.1016/j.bpj.2016.03.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 11/20/2022] Open
Abstract
Filopodia are ubiquitous fingerlike protrusions, spawned by many eukaryotic cells, to probe and interact with their environments. Polymerization dynamics of actin filaments, comprising the structural core of filopodia, largely determine their instantaneous lengths and overall lifetimes. The polymerization reactions at the filopodial tip require transport of G-actin, which enter the filopodial tube from the filopodial base and diffuse toward the filament barbed ends near the tip. Actin filaments are mechanically coupled into a tight bundle by cross-linker proteins. Interestingly, many of these proteins are relatively short, restricting the free diffusion of cytosolic G-actin throughout the bundle and, in particular, its penetration into the bundle core. To investigate the effect of steric restrictions on G-actin diffusion by the porous structure of filopodial actin filament bundle, we used a particle-based stochastic simulation approach. We discovered that excluded volume interactions result in partial and then full collapse of central filaments in the bundle, leading to a hollowed-out structure. The latter may further collapse radially due to the activity of cross-linking proteins, hence producing conical-shaped filament bundles. Interestingly, electron microscopy experiments on mature filopodia indeed frequently reveal actin bundles that are narrow at the tip and wider at the base. Overall, our work demonstrates that excluded volume effects in the context of reaction-diffusion processes in porous networks may lead to unexpected geometric growth patterns and complicated, history-dependent dynamics of intermediate metastable configurations.
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Figard L, Wang M, Zheng L, Golding I, Sokac AM. Membrane Supply and Demand Regulates F-Actin in a Cell Surface Reservoir. Dev Cell 2017; 37:267-78. [PMID: 27165556 DOI: 10.1016/j.devcel.2016.04.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 11/19/2015] [Accepted: 04/12/2016] [Indexed: 11/16/2022]
Abstract
Cells store membrane in surface reservoirs of pits and protrusions. These membrane reservoirs facilitate cell shape change and buffer mechanical stress, but we do not know how reservoir dynamics are regulated. During cellularization, the first cytokinesis in Drosophila embryos, a reservoir of microvilli unfolds to fuel cleavage furrow ingression. We find that regulated exocytosis adds membrane to the reservoir before and during unfolding. Dynamic F-actin deforms exocytosed membrane into microvilli. Single microvilli extend and retract in ∼20 s, while the overall reservoir is depleted in sync with furrow ingression over 60-70 min. Using pharmacological and genetic perturbations, we show that exocytosis promotes microvillar F-actin assembly, while furrow ingression controls microvillar F-actin disassembly. Thus, reservoir F-actin and, consequently, reservoir dynamics are regulated by membrane supply from exocytosis and membrane demand from furrow ingression.
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Affiliation(s)
- Lauren Figard
- Verna & Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, BCM125, Houston, TX 77030, USA; Graduate Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mengyu Wang
- Verna & Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, BCM125, Houston, TX 77030, USA; Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Liuliu Zheng
- Verna & Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, BCM125, Houston, TX 77030, USA
| | - Ido Golding
- Verna & Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, BCM125, Houston, TX 77030, USA; Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
| | - Anna Marie Sokac
- Verna & Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, BCM125, Houston, TX 77030, USA; Graduate Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX 77030, USA.
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Functional Actin Networks under Construction: The Cooperative Action of Actin Nucleation and Elongation Factors. Trends Biochem Sci 2017; 42:414-430. [DOI: 10.1016/j.tibs.2017.03.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 03/04/2017] [Accepted: 03/07/2017] [Indexed: 12/31/2022]
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38
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Fukuta M, Ono A, Nawa Y, Inami W, Shen L, Kawata Y, Terekawa S. Cell structure imaging with bright and homogeneous nanometric light source. JOURNAL OF BIOPHOTONICS 2017; 10:503-510. [PMID: 27274004 DOI: 10.1002/jbio.201500308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 04/19/2016] [Accepted: 05/18/2016] [Indexed: 06/06/2023]
Abstract
Label-free optical nano-imaging of dendritic structures and intracellular granules in biological cells is demonstrated using a bright and homogeneous nanometric light source. The optical nanometric light source is excited using a focused electron beam. A zinc oxide (ZnO) luminescent thin film was fabricated by atomic layer deposition (ALD) to produce the nanoscale light source. The ZnO film formed by ALD emitted the bright, homogeneous light, unlike that deposited by another method. The dendritic structures of label-free macrophage receptor with collagenous structure-expressing CHO cells were clearly visualized below the diffraction limit. The inner fiber structure was observed with 120 nm spatial resolution. Because the bright homogeneous emission from the ZnO film suppresses the background noise, the signal-to-noise ratio (SNR) for the imaging results was greater than 10. The ALD method helps achieve an electron beam excitation assisted microscope with high spatial resolution and high SNR.
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Affiliation(s)
- Masahiro Fukuta
- Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka, Hamamatsu, 432-8561, Japan
| | - Atsushi Ono
- Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka, Hamamatsu, 432-8561, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honmachi, Kawaguchi, Saitama, 332-0012, Japan
| | - Yasunori Nawa
- Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka, Hamamatsu, 432-8561, Japan
| | - Wataru Inami
- Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka, Hamamatsu, 432-8561, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honmachi, Kawaguchi, Saitama, 332-0012, Japan
| | - Lin Shen
- CREST, Japan Science and Technology Agency, 4-1-8 Honmachi, Kawaguchi, Saitama, 332-0012, Japan
| | - Yoshimasa Kawata
- Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka, Hamamatsu, 432-8561, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honmachi, Kawaguchi, Saitama, 332-0012, Japan
| | - Susumu Terekawa
- CREST, Japan Science and Technology Agency, 4-1-8 Honmachi, Kawaguchi, Saitama, 332-0012, Japan
- Photon Medical Research Center, Hamamatsu University School of Medicine, 1-20-1 Hondayama, Higashi, Hamamatsu, 431-3192, Japan
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39
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Kage F, Winterhoff M, Dimchev V, Mueller J, Thalheim T, Freise A, Brühmann S, Kollasser J, Block J, Dimchev G, Geyer M, Schnittler HJ, Brakebusch C, Stradal TEB, Carlier MF, Sixt M, Käs J, Faix J, Rottner K. FMNL formins boost lamellipodial force generation. Nat Commun 2017; 8:14832. [PMID: 28327544 PMCID: PMC5364437 DOI: 10.1038/ncomms14832] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 02/03/2017] [Indexed: 01/16/2023] Open
Abstract
Migration frequently involves Rac-mediated protrusion of lamellipodia, formed by Arp2/3 complex-dependent branching thought to be crucial for force generation and stability of these networks. The formins FMNL2 and FMNL3 are Cdc42 effectors targeting to the lamellipodium tip and shown here to nucleate and elongate actin filaments with complementary activities in vitro. In migrating B16-F1 melanoma cells, both formins contribute to the velocity of lamellipodium protrusion. Loss of FMNL2/3 function in melanoma cells and fibroblasts reduces lamellipodial width, actin filament density and -bundling, without changing patterns of Arp2/3 complex incorporation. Strikingly, in melanoma cells, FMNL2/3 gene inactivation almost completely abolishes protrusion forces exerted by lamellipodia and modifies their ultrastructural organization. Consistently, CRISPR/Cas-mediated depletion of FMNL2/3 in fibroblasts reduces both migration and capability of cells to move against viscous media. Together, we conclude that force generation in lamellipodia strongly depends on FMNL formin activity, operating in addition to Arp2/3 complex-dependent filament branching.
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Affiliation(s)
- Frieda Kage
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Moritz Winterhoff
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Vanessa Dimchev
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Jan Mueller
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Tobias Thalheim
- Soft Matter Physics Group, Institut für experimentelle Physik I, Leipzig University, Linnéstraße 5, 04103 Leipzig, Germany
| | - Anika Freise
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Stefan Brühmann
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Jana Kollasser
- Biomedical Institute, BRIC, University of Copenhagen, DK-2200 Copenhagen, Denmark.,Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Jennifer Block
- Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Georgi Dimchev
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Matthias Geyer
- Institute of Innate Immunity, Department of Structural Immunology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany
| | - Hans-Joachim Schnittler
- Institute of Anatomy and Vascular Biology, Westfälische Wilhelms-Universität Münster, Vesaliusweg 2-4, 48149 Münster, Germany
| | - Cord Brakebusch
- Biomedical Institute, BRIC, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Theresia E B Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Marie-France Carlier
- Cytoskeleton Dynamics and Motility Group, Laboratoire d'Enzymologie et Biochimie Structurales, Centre de Recherche de Gif, CNRS, Gif-sur-Yvette 91198, France
| | - Michael Sixt
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Josef Käs
- Soft Matter Physics Group, Institut für experimentelle Physik I, Leipzig University, Linnéstraße 5, 04103 Leipzig, Germany
| | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
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40
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Integrin-Dependent Regulation of Small GTPases: Role in Cell Migration. J Indian Inst Sci 2017. [DOI: 10.1007/s41745-016-0010-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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41
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MyTH4-FERM myosins have an ancient and conserved role in filopod formation. Proc Natl Acad Sci U S A 2016; 113:E8059-E8068. [PMID: 27911821 DOI: 10.1073/pnas.1615392113] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The formation of filopodia in Metazoa and Amoebozoa requires the activity of myosin 10 (Myo10) in mammalian cells and of Dictyostelium unconventional myosin 7 (DdMyo7) in the social amoeba Dictyostelium However, the exact roles of these MyTH4-FERM myosins (myosin tail homology 4-band 4.1, ezrin, radixin, moesin; MF) in the initiation and elongation of filopodia are not well defined and may reflect conserved functions among phylogenetically diverse MF myosins. Phylogenetic analysis of MF myosin domains suggests that a single ancestral MF myosin existed with a structure similar to DdMyo7, which has two MF domains, and that subsequent duplications in the metazoan lineage produced its functional homolog Myo10. The essential functional features of the DdMyo7 myosin were identified using quantitative live-cell imaging to characterize the ability of various mutants to rescue filopod formation in myo7-null cells. The two MF domains were found to function redundantly in filopod formation with the C-terminal FERM domain regulating both the number of filopodia and their elongation velocity. DdMyo7 mutants consisting solely of the motor plus a single MyTH4 domain were found to be capable of rescuing the formation of filopodia, establishing the minimal elements necessary for the function of this myosin. Interestingly, a chimeric myosin with the Myo10 MF domain fused to the DdMyo7 motor also was capable of rescuing filopod formation in the myo7-null mutant, supporting fundamental functional conservation between these two distant myosins. Together, these findings reveal that MF myosins have an ancient and conserved role in filopod formation.
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42
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Weichsel J, Geissler PL. The More the Tubular: Dynamic Bundling of Actin Filaments for Membrane Tube Formation. PLoS Comput Biol 2016; 12:e1004982. [PMID: 27384915 PMCID: PMC4934920 DOI: 10.1371/journal.pcbi.1004982] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 05/13/2016] [Indexed: 02/01/2023] Open
Abstract
Tubular protrusions are a common feature of living cells, arising from polymerization of stiff protein filaments against a comparably soft membrane. Although this process involves many accessory proteins in cells, in vitro experiments indicate that similar tube-like structures can emerge without them, through spontaneous bundling of filaments mediated by the membrane. Using theory and simulation of physical models, we have elaborated how nonequilibrium fluctuations in growth kinetics and membrane shape can yield such protrusions. Enabled by a new grand canonical Monte Carlo method for membrane simulation, our work reveals a cascade of dynamical transitions from individually polymerizing filaments to highly cooperatively growing bundles as a dynamical bottleneck to tube formation. Filament network organization as well as adhesion points to the membrane, which bias filament bending and constrain membrane height fluctuations, screen the effective attractive interactions between filaments, significantly delaying bundling and tube formation.
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Affiliation(s)
- Julian Weichsel
- Department of Chemistry, University of California, Berkeley, California, United States of America
| | - Phillip L. Geissler
- Department of Chemistry, University of California, Berkeley, California, United States of America
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43
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Moazedi-Fuerst FC, Gruber G, Stradner MH, Guidolin D, Jones JC, Bodo K, Wagner K, Peischler D, Krischan V, Weber J, Sadoghi P, Glehr M, Leithner A, Graninger WB. Effect of Laminin-A4 inhibition on cluster formation of human osteoarthritic chondrocytes. J Orthop Res 2016; 34:419-26. [PMID: 26295200 PMCID: PMC5727909 DOI: 10.1002/jor.23036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 08/14/2015] [Indexed: 02/04/2023]
Abstract
Formation of chondrocyte clusters is not only a morphological sign of osteoarthritis but it is also observed in cell culture. Active locomotion of chondrocytes is controlled by integrins in vitro. Integrins bind to Laminin-A4 (LAMA4), a protein that is highly expressed in vivo in clusters of hypertrophic chondrocytes. We tested if LAMA4 is relevant for cluster formation. Human chondrocytes were cultured in a 2D matrigel model and treated with different concentrations of a monoclonal inhibitory anti-LAMA4-antibody. Migration and cluster formation was analysed using live cell imaging technique. Full genome gene expression analysis was performed to assess the effect of LAMA4 inhibition. The data set were screened for genes relevant to cell motility. F-actin staining was performed to document cytoskeletal changes. Anti-LAMA4 treatment significantly reduced the rate of cluster formation in human chondrocytes. Cells changed their surface morphology and exhibited fewer protrusions. Expression of genes associated with cellular motility and migration was affected by anti-LAMA4 treatment. LAMA4-integrin signalling affects chondrocyte morphology and gene expression in vitro, thereby contributing to cluster formation in human osteoarthritic chondrocytes.
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Affiliation(s)
| | - Gerald Gruber
- Department of Orthopaedic Surgery, Medical University Graz
| | | | - Diego Guidolin
- Department of Molecular Medicine, Section of Anatomy, University of Padua
| | - Jonathan C. Jones
- Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago
| | - Koppany Bodo
- Department of Pathology, Medical University Graz
| | - Karin Wagner
- Center of Medical Research, Corefacility Molecular biology, Medical University Graz
| | | | - Verena Krischan
- Division of Rheumatology and Immunology, Medical University Graz
| | - Jennifer Weber
- Division of Rheumatology and Immunology, Medical University Graz
| | | | - Mathias Glehr
- Department of Orthopaedic Surgery, Medical University Graz
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44
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Zhang N, Bing T, Shen L, Song R, Wang L, Liu X, Liu M, Li J, Tan W, Shangguan D. Intercellular Connections Related to Cell-Cell Crosstalk Specifically Recognized by an Aptamer. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201510786] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Nan Zhang
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
- University of the Chinese Academy of Sciences; Beijing 100049 P.R. China
| | - Tao Bing
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
| | - Luyao Shen
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
- University of the Chinese Academy of Sciences; Beijing 100049 P.R. China
| | - Rusheng Song
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
- University of the Chinese Academy of Sciences; Beijing 100049 P.R. China
| | - Linlin Wang
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
- University of the Chinese Academy of Sciences; Beijing 100049 P.R. China
| | - Xiangjun Liu
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
| | - Meirong Liu
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
| | - Juan Li
- Department of Chemistry; Center for Research at the Bio/Nano Interface; Health Cancer Center; UF Genetics Institute; McKnight Brain Institute; University of Florida; Gainesville FL 32611-7200 USA
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics; College of Biology and College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P.R. China
| | - Weihong Tan
- Department of Chemistry; Center for Research at the Bio/Nano Interface; Health Cancer Center; UF Genetics Institute; McKnight Brain Institute; University of Florida; Gainesville FL 32611-7200 USA
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics; College of Biology and College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P.R. China
| | - Dihua Shangguan
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
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45
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Zhang N, Bing T, Shen L, Song R, Wang L, Liu X, Liu M, Li J, Tan W, Shangguan D. Intercellular Connections Related to Cell-Cell Crosstalk Specifically Recognized by an Aptamer. Angew Chem Int Ed Engl 2016; 55:3914-8. [DOI: 10.1002/anie.201510786] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/26/2016] [Indexed: 01/23/2023]
Affiliation(s)
- Nan Zhang
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
- University of the Chinese Academy of Sciences; Beijing 100049 P.R. China
| | - Tao Bing
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
| | - Luyao Shen
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
- University of the Chinese Academy of Sciences; Beijing 100049 P.R. China
| | - Rusheng Song
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
- University of the Chinese Academy of Sciences; Beijing 100049 P.R. China
| | - Linlin Wang
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
- University of the Chinese Academy of Sciences; Beijing 100049 P.R. China
| | - Xiangjun Liu
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
| | - Meirong Liu
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
| | - Juan Li
- Department of Chemistry; Center for Research at the Bio/Nano Interface; Health Cancer Center; UF Genetics Institute; McKnight Brain Institute; University of Florida; Gainesville FL 32611-7200 USA
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics; College of Biology and College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P.R. China
| | - Weihong Tan
- Department of Chemistry; Center for Research at the Bio/Nano Interface; Health Cancer Center; UF Genetics Institute; McKnight Brain Institute; University of Florida; Gainesville FL 32611-7200 USA
- Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics; College of Biology and College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 P.R. China
| | - Dihua Shangguan
- Beijing National Laboratory for Molecular Sciences; Key Laboratory of Analytical Chemistry for Living Biosystems; Institute of Chemistry; Chinese Academy of Sciences; Beijing 100190 P.R. China
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46
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Leijnse N, Oddershede LB, Bendix PM. An updated look at actin dynamics in filopodia. Cytoskeleton (Hoboken) 2016; 72:71-9. [PMID: 25786787 DOI: 10.1002/cm.21216] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 11/10/2022]
Abstract
Cells dynamically interact with and probe their environment by growing finger-like structures named filopodia. The dynamics of filopodia are mainly caused by the actin rich core or shaft which sits inside the filopodial membrane and continuously undergoes changes like growth, shrinking, bending, and rotation. Recent experiments combining advanced imaging and manipulation tools have provided detailed quantitative data on the correlation between mechanical properties of filopodia, their molecular composition, and the dynamic architecture of the actin structure. These experiments have revealed how retrograde flow and twisting of the actin shaft within filopodia can generate traction on external substrates. Previously, the mechanism behind filopodial pulling was mainly attributed to retrograde flow of actin, but recent experiments have shown that rotational dynamics can also contribute to the traction force. Although force measurements have indicated a step-like behavior in filopodial pulling, no direct evidence has been provided to link this behavior to a molecular motor like myosin. Therefore, the underlying biochemical and mechanical mechanisms behind filopodial force generation still remain to be resolved.
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Affiliation(s)
- Natascha Leijnse
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark; Lundbeck Foundation Center for Biomembranes in Nanomedicine, University of Copenhagen, 2100, Copenhagen, Denmark
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47
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Steffen A, Stradal TEB, Rottner K. Signalling Pathways Controlling Cellular Actin Organization. Handb Exp Pharmacol 2016; 235:153-178. [PMID: 27757765 DOI: 10.1007/164_2016_35] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The actin cytoskeleton is essential for morphogenesis and virtually all types of cell shape changes. Reorganization is per definition driven by continuous disassembly and re-assembly of actin filaments, controlled by major, ubiquitously operating machines. These are specifically employed by the cell to tune its activities in accordance with respective environmental conditions or to satisfy specific needs.Here we sketch some fundamental signalling pathways established to contribute to the reorganization of specific actin structures at the plasma membrane. Rho-family GTPases are at the core of these pathways, and dissection of their precise contributions to actin reorganization in different cell types and tissues will thus continue to improve our understanding of these important signalling nodes. Furthermore, we will draw your attention to the emerging theme of actin reorganization on intracellular membranes, its functional relation to Rho-GTPase signalling, and its relevance for the exciting phenomenon autophagy.
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Affiliation(s)
- Anika Steffen
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Theresia E B Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
| | - Klemens Rottner
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.,Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106, Braunschweig, Germany
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48
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Formins at the Junction. Trends Biochem Sci 2015; 41:148-159. [PMID: 26732401 DOI: 10.1016/j.tibs.2015.12.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 12/01/2015] [Accepted: 12/04/2015] [Indexed: 12/21/2022]
Abstract
The actin cytoskeleton and adhesion junctions are physically and functionally coupled at the cell-cell interface between epithelial cells. The actin regulatory complex Arp2/3 has an established role in the turnover of junctional actin; however, the role of formins, the largest group of actin regulators, is less clear. Formins dynamically shape the actin cytoskeleton and have various functions within cells. In this review we describe recent progress on how formins regulate actin dynamics at cell-cell contacts and highlight formin functions during polarized protein traffic necessary for epithelialization.
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49
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Young LE, Heimsath EG, Higgs HN. Cell type-dependent mechanisms for formin-mediated assembly of filopodia. Mol Biol Cell 2015; 26:4646-59. [PMID: 26446836 PMCID: PMC4678021 DOI: 10.1091/mbc.e15-09-0626] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/01/2015] [Indexed: 11/11/2022] Open
Abstract
Filopodia are finger-like protrusions from the plasma membrane and are of fundamental importance to cellular physiology, but the mechanisms governing their assembly are still in question. One model, called convergent elongation, proposes that filopodia arise from Arp2/3 complex-nucleated dendritic actin networks, with factors such as formins elongating these filaments into filopodia. We test this model using constitutively active constructs of two formins, FMNL3 and mDia2. Surprisingly, filopodial assembly requirements differ between suspension and adherent cells. In suspension cells, Arp2/3 complex is required for filopodial assembly through either formin. In contrast, a subset of filopodia remains after Arp2/3 complex inhibition in adherent cells. In adherent cells only, mDia1 and VASP also contribute to filopodial assembly, and filopodia are disproportionately associated with focal adhesions. We propose an extension of the existing models for filopodial assembly in which any cluster of actin filament barbed ends in proximity to the plasma membrane, either Arp2/3 complex dependent or independent, can initiate filopodial assembly by specific formins.
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Affiliation(s)
- Lorna E Young
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Ernest G Heimsath
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Henry N Higgs
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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50
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Grega-Larson NE, Crawley SW, Erwin AL, Tyska MJ. Cordon bleu promotes the assembly of brush border microvilli. Mol Biol Cell 2015; 26:3803-15. [PMID: 26354418 PMCID: PMC4626065 DOI: 10.1091/mbc.e15-06-0443] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/02/2015] [Indexed: 01/24/2023] Open
Abstract
Microvilli are actin-based protrusions that amplify plasma membrane area and mediate interactions with the extracellular environment. We found that the multifunctional actin regulator cordon bleu promotes the growth of intestinal brush border microvilli. These results provide a new framework for investigating brush border biogenesis. Microvilli are actin-based protrusions found on the surface of diverse cell types, where they amplify membrane area and mediate interactions with the external environment. In the intestinal tract, these protrusions play central roles in nutrient absorption and host defense and are therefore essential for maintaining homeostasis. However, the mechanisms controlling microvillar assembly remain poorly understood. Here we report that the multifunctional actin regulator cordon bleu (COBL) promotes the growth of brush border (BB) microvilli. COBL localizes to the base of BB microvilli via a mechanism that requires its proline-rich N-terminus. Knockdown and overexpression studies show that COBL is needed for BB assembly and sufficient to induce microvillar growth using a mechanism that requires functional WH2 domains. We also find that COBL acts downstream of the F-BAR protein syndapin-2, which drives COBL targeting to the apical domain. These results provide insight into a mechanism that regulates microvillar growth during epithelial differentiation and have significant implications for understanding the maintenance of intestinal homeostasis.
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Affiliation(s)
- Nathan E Grega-Larson
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240
| | - Scott W Crawley
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240
| | - Amanda L Erwin
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240
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