DOCSLIB.ORG

Formins at a Glance

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Formins at a Glance Cell Science at a Glance 1 Formins at a glance common properties that apply to most protein family (encoded by 15 genes in formins, and highlighting recent advances mammals, two in S. cerevisiae, three in understanding formin structure, in Saccharomyces pombe, and six in Dennis Breitsprecher and mechanism, activity and regulation at the Drosophila melangastor) have been Bruce L. Goode* molecular and cellular levels. demonstrated to have crucial roles in an Rosenstiel Basic Medical Sciences Research Center, Formins were first identified in flies, increasingly wide range of cytoskeleton- Department of Biology, Brandeis University, 415 mice and yeast as genes that, when based processes (as illustrated in the South Street, Waltham, MA 02454, USA Poster). *Author for correspondence ([email protected]) mutated, cause severe defects in cytokinesis, polarity, and cell and tissue Journal of Cell Science 126, 1–7 morphogenesis (Mass et al., 1990; Cellular functions of formins ß 2013. Published by The Company of Biologists Ltd doi: 10.1242/jcs.107250 Jackson-Grusby et al., 1992; Castrillon In yeast, formins have an essential role in and Wasserman, 1994; Kohno et al., the assembly of cytokinetic rings and Formins are conserved actin polymerization 1996). Subsequent studies in budding cables that direct intracellular transport machines that have instrumental roles in yeast Saccharomyces cerevisiae revealed (Chang, 1999; Feierbach and Chang, 2001; controlling rearrangements of the actin that formins directly nucleate the assembly Evangelista et al., 2002; Dong et al., 2003; cytoskeleton and have recently been of actin filaments, and that these activities Cheung and Wu, 2004; Ingouff et al., shown to directly regulate microtubule are essential in vivo for the assembly of 2005; Cheung et al., 2010). In animal cells, dynamics. Here, and on the accompanying actin cables that direct polarized cell formins are required for the assembly of poster, we aim to organize a rapidly growth (Evangelista et al., 2002; Pruyne filopodia (Pellegrin and Mellor, 2005; expanding body of literature on this et al., 2002; Sagot et al., 2002a; Sagot et al., Schirenbeck et al., 2005; Yang et al., diverse protein family, summarizing the 2002b). Since then, members of this large 2007; Block et al., 2008; Matusek et al., Journal of Cell Science (See poster insert) 2 Journal of Cell Science 126 (1) 2008; Harris et al., 2010), lamellipodia autoinhibited through DID–DAD formins AFH1, formin1 and class II (Yang et al., 2007; Sarmiento et al., 2008; interactions. Recent crystallographic and formin, directly bind phospholipid Block et al., 2012), stress fibers (Ishizaki single-particle electron microscopy studies membranes (Cheung et al., 2010; et al., 2001; Satoh and Tominaga, 2001; show that, in the autoinhibited Ramalingam et al., 2010; Gorelik et al., Gasteier et al., 2003; Peng et al., 2003; conformation, the N-terminus physically 2011; Martinie`re et al., 2011; van Hotulainen and Lappalainen, 2006; Sato obstructs the ability of the C-terminus to Gisbergen et al., 2012). These et al., 2006; Takeya et al., 2008), polymerize actin (Nezami et al., 2010; observations show that localization and cytoplasmic actin networks used for long- Otomo et al., 2010; Maiti et al., 2012). activation of formins depend on their range vesicle transport (Leader et al., 2002; Binding of active Rho-GTPases to GBD diverse interactions and that localization Azoury et al., 2008; Li et al., 2008; Pfender activates the formin by releasing these and activation, in some cases, serve as et al., 2011; Schuh, 2011), cytokinetic DID–DAD interactions. However, convergent inputs from multiple signalling actin rings (Severson et al., 2002; activation is noticeably incomplete (Li pathways. Watanabe et al., 2008) and phagocytic and Higgs, 2003; Maiti et al., 2012), cups (Brandt et al., 2007). Formins also suggesting that other factors are required Biochemical activities of formins have essential roles in physiological to fully activate formins. Formins are large, dimeric multi-domain processes ranging from cell motility in A variety of Rho-GTPases recruit DRFs proteins with a modular design (see the immune system (Yayoshi-Yamamoto to different locations in the cell for poster). Their signature features are the et al., 2000; Eisenmann et al., 2007; Shi localized actin assembly (Evangelista C-terminal formin homology 1 and 2 et al., 2009), to gastrulation and neural et al., 1997; Watanabe et al., 1997; domains (FH1 and FH2, respectively) tube closure (Habas et al., 2001; Sato et al., Ishizaki et al., 2001; Nakano et al., 2002; (Chesarone et al., 2010; Scho¨nichen and 2006; Lai et al., 2008), heart Tolliday et al., 2002; Pellegrin and Mellor, Geyer, 2010). The only known exception is morphogenesis (Iskratsch et al., 2010; Li 2005; Seth et al., 2006; Martin et al., 2007; Dictyostelium ForC, which lacks an FH1 et al., 2011), kidney morphogenesis Block et al., 2012) (see Poster), yet domain (Rivero et al., 2005). Most formins (Brown et al., 2010; Boyer et al., 2011a; additional factors can also regulate also have C-terminal tail regions that, Boyer et al., 2011b), and dendritic spine formins. For example, the S. cerevisiae sometimes, include DAD domains and/or formation in neurons. Some of these formin Bnr1 and S. pombe formin Cdc12 Wiskott-Aldrich syndrome homology functions depend on the actin nucleation each harbor at least two separate region 2 (WH2)-like domains. In and elongation activities of formins localization sequences that independently comparison, the N-terminal halves of (Bartolini et al., 2008; Andre´s-Delgado target the formin in vivo (Gao et al., 2010), formins are more variable and have main et al., 2010; Madrid et al., 2010; Andre´s- suggesting that a combination of cues and roles in directing their localization. Delgado et al., 2012; Ramabhadran et al., binding partners control formin Most purified formins exhibit the 2012; Stastna et al., 2012), which have recruitment. Indeed, one of the sequences following three activities: (1) nucleation been demonstrated by investigating point in Bnr1 was shown to interact with a of actin assembly, (2) processive mutations that impair in these activities septin-associated kinase that controls Bnr1 movement on growing barbed ends of Journal of Cell Science (Xu et al., 2004; Lu et al., 2007; function (Buttery et al., 2012). In addition, actin filaments while protecting them Ramabhadran et al., 2012). However, for the S. cerevisiae DRF Bni1 is from capping proteins and (3) profilin- many of the other in vivo functions of phosphorylated at its N- and C-termini by dependent acceleration of actin filament formins, it has not yet been determined Prk1 kinase, which facilitates its release elongation. Additional activities in which of their activities are required. from autoinhibition (Wang et al., 2009). In different subsets of formins include Moreover, some formins exhibit activities mammals, the formin protein diaphanous MT binding (see below) and actin beyond actin assembly, e.g. actin bundling, homolog 2 (DIAPH2, hereafter referred to filament bundling, severing and/or severing, depolymerization and microtubule as mDia3) is phosphorylated by Aurora B depolymerization (Harris et al., 2004; (MT) binding (see below). Thus, an kinase (Cheng et al., 2011), the formin Michelot et al., 2005; Moseley and important future challenge is to develop homology domain proteins 1 and 3 Goode, 2005; Chhabra and Higgs, 2006; new mutants as tools that are capable of (FHOD1 and FHOD3, respectively) are Harris and Higgs, 2006; Esue et al., 2008; separately disrupting each formin activity. phosphorylated by cGMP-dependent Barko´ et al., 2010; Harris et al., 2010; protein kinase 1 (PRKG1) and casein Machaidze et al., 2010; Scott et al., 2011; Localization and activation of formins kinase 2 subunit a (CSNK2A1, also Skillman et al., 2012). All known Formins are recruited and activated at known as CK2) (Hannemann et al., 2008; interactions of formins with actin and different sites in cells, where they Iskratsch et al., 2010; Iskratsch et al., MTs are mediated by the FH1 and FH2 perform their diverse roles in cytoskeletal 2012), and mDia2 and FHOD1 are domains and/or the tail regions. The FH1 reorganization. Of the 15 vertebrate activated through phosphorylation by domain is predicted to be extended and formins, the largest subset are Rho-associated protein kinase (ROCK) unstructured, and contains multiple Diaphanous-related formins (DRFs), (Takeya et al., 2008; Staus et al., 2011). proline-rich motifs that recruit complexes which have an N-terminal GTPase- Inverted formin-2 (INF2) and formin-like that consist of actin monomers and binding domain (GBD), an adjacent DID protein 2 (FMNL2, also known as FRL3) profilin, a small abundant protein that (Diaphanous inhibitory domain) and a C- are also farnesylated and myristoylated, binds the majority of ATP–actin terminal DAD (Diaphanous autoregulatory respectively, which promotes their monomers in cells (Chang et al., 1997; domain) (see Poster) (Alberts, 2001; Li and membrane targeting (Chhabra et al., Imamura et al., 1997; Sagot et al., 2002b; Higgs, 2003; Otomo et al., 2005a; Rose 2009; Block et al., 2012). Moreover, Kovar et al., 2003; Kovar et al., 2005). et al., 2005; Otomo et al., 2010). DRFs are mDia1 and mDia2, as well as the plant The FH2 domain forms a ring-shaped Journal of Cell Science 126 (1) 3 anti-parallel dimer, in which the two contributions by their FH1 and FH2 perplexingly, Spire inhibits rather than halves are held together by interactions of domains, and the tail regions. enhances the nucleation activity of FMN ‘lasso’ and ‘post’ segments, generating a Although most formins promote actin in vitro (Quinlan et al., 2007; Vizcarra flexibly tethered dimer (Xu et al., 2004). nucleation and elongation, the strength of et al., 2011; Zeth et al., 2011), suggesting FH2 dimers bind with high affinity to the these activities can vary drastically. For that additional factors are required to barbed ends of actin filaments (Pruyne example, S. pombe Cdc12 is a potent activate collaborative actin assembly et al., 2002; Kovar et al., 2003; Zigmond, nucleator with a nucleation efficiency of through Spire–FMN.
Load more

Recommended publications
  • Snapshot: Formins Christian Baarlink, Dominique Brandt, and Robert Grosse University of Marburg, Marburg 35032, Germany
    SnapShot: Formins Christian Baarlink, Dominique Brandt, and Robert Grosse University of Marburg, Marburg 35032, Germany Formin Regulators Localization Cellular Function Disease Association DIAPH1/DIA1 RhoA, RhoC Cell cortex, Polarized cell migration, microtubule stabilization, Autosomal-dominant nonsyndromic deafness (DFNA1), myeloproliferative (mDia1) phagocytic cup, phagocytosis, axon elongation defects, defects in T lymphocyte traffi cking and proliferation, tumor cell mitotic spindle invasion, defects in natural killer lymphocyte function DIAPH2 Cdc42 Kinetochore Stable microtubule attachment to kinetochore for Premature ovarian failure (mDia3) chromosome alignment DIAPH3 Rif, Cdc42, Filopodia, Filopodia formation, removing the nucleus from Increased chromosomal deletion of gene locus in metastatic tumors (mDia2) Rac, RhoB, endosomes erythroblast, endosome motility, microtubule DIP* stabilization FMNL1 (FRLα) Cdc42 Cell cortex, Phagocytosis, T cell polarity Overexpression is linked to leukemia and non-Hodgkin lymphoma microtubule- organizing center FMNL2/FRL3/ RhoC ND Cell motility Upregulated in metastatic colorectal cancer, chromosomal deletion is FHOD2 associated with mental retardation FMNL3/FRL2 Constituently Stress fi bers ND ND active DAAM1 Dishevelled Cell cortex Planar cell polarity ND DAAM2 ND ND ND Overexpressed in schizophrenia patients Human (Mouse) FHOD1 ROCK Stress fi bers Cell motility FHOD3 ND Nestin, sarcomere Organizing sarcomeres in striated muscle cells Single-nucleotide polymorphisms associated with type 1 diabetes
    [Show full text]
  • How Models and Biological Experimentation Have Come Together to Reveal Mechanisms of Cytokinesis Daniel B
    © 2018. Published by The Company of Biologists Ltd | Journal of Cell Science (2018) 131, jcs203570. doi:10.1242/jcs.203570 REVIEW Unite to divide – how models and biological experimentation have come together to reveal mechanisms of cytokinesis Daniel B. Cortes1, Adriana Dawes2, Jian Liu3, Masoud Nickaeen4, Wanda Strychalski5 and Amy Shaub Maddox1,* ABSTRACT these systems. Thus, cytokinesis can serve as a paradigm to Cytokinesis is the fundamental and ancient cellular process by which understand diverse behaviors of cellular motility. one cell physically divides into two. Cytokinesis in animal and fungal Mathematical modeling (see Glossary), combined with biological ‘ ’ cells is achieved by contraction of an actomyosin cytoskeletal ring experimentation (i.e. wet lab approaches including microscopy, assembled in the cell cortex, typically at the cell equator. Cytokinesis genetics, biochemistry and biophysics), has significantly advanced ‘ ’ is essential for the development of fertilized eggs into multicellular our understanding of cytokinesis. Herein, we use the word modeling organisms and for homeostatic replenishment of cells. Correct to collectively refer to diverse theoretical approaches, in which execution of cytokinesis is also necessary for genome stability and biological, biochemical and biophysical processes are described with the evasion of diseases including cancer. Cytokinesis has fascinated mathematical equations. These approaches, often historically rooted scientists for well over a century, but its speed and dynamics make in, and motivated by, problems in physics and chemistry, include experiments challenging to perform and interpret. The presence continuum mechanics modeling and agent-based modeling (see of redundant mechanisms is also a challenge to understand Glossary). The following references can serve as a starting point for cytokinesis, leaving many fundamental questions unresolved.
    [Show full text]
  • Profilin and Formin Constitute a Pacemaker System for Robust Actin
    RESEARCH ARTICLE Profilin and formin constitute a pacemaker system for robust actin filament growth Johanna Funk1, Felipe Merino2, Larisa Venkova3, Lina Heydenreich4, Jan Kierfeld4, Pablo Vargas3, Stefan Raunser2, Matthieu Piel3, Peter Bieling1* 1Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany; 2Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany; 3Institut Curie UMR144 CNRS, Paris, France; 4Physics Department, TU Dortmund University, Dortmund, Germany Abstract The actin cytoskeleton drives many essential biological processes, from cell morphogenesis to motility. Assembly of functional actin networks requires control over the speed at which actin filaments grow. How this can be achieved at the high and variable levels of soluble actin subunits found in cells is unclear. Here we reconstitute assembly of mammalian, non-muscle actin filaments from physiological concentrations of profilin-actin. We discover that under these conditions, filament growth is limited by profilin dissociating from the filament end and the speed of elongation becomes insensitive to the concentration of soluble subunits. Profilin release can be directly promoted by formin actin polymerases even at saturating profilin-actin concentrations. We demonstrate that mammalian cells indeed operate at the limit to actin filament growth imposed by profilin and formins. Our results reveal how synergy between profilin and formins generates robust filament growth rates that are resilient to changes in the soluble subunit concentration. DOI: https://doi.org/10.7554/eLife.50963.001 *For correspondence: peter.bieling@mpi-dortmund. mpg.de Introduction Competing interests: The Eukaryotic cells move, change their shape and organize their interior through dynamic actin net- authors declare that no works.
    [Show full text]
  • Role of G-Protein Regulation of Formins During Gradient Tracking in Saccharomyces Cerevisiae
    The University of Maine DigitalCommons@UMaine Honors College Spring 5-2017 Role of G-protein Regulation of Formins during Gradient Tracking in Saccharomyces cerevisiae Stephen Soohey University of Maine Follow this and additional works at: https://digitalcommons.library.umaine.edu/honors Recommended Citation Soohey, Stephen, "Role of G-protein Regulation of Formins during Gradient Tracking in Saccharomyces cerevisiae" (2017). Honors College. 261. https://digitalcommons.library.umaine.edu/honors/261 This Honors Thesis is brought to you for free and open access by DigitalCommons@UMaine. It has been accepted for inclusion in Honors College by an authorized administrator of DigitalCommons@UMaine. For more information, please contact [email protected]. ROLE OF G-PROTEIN REGULATION OF FORMINS DURING GRADIENT TRACKING IN SACCHAROMYCES CEREVISIAE by Stephen C. Soohey A Thesis Submitted in Partial Fulfillment of the Requirements for a Degree with Honors (Molecular and Cellular Biology) The Honors College University of Maine May 2017 Advisory Committee: Joshua Kelley, Assistant Professor of Biochemistry, Advisor Sally Molloy, Assistant Professor of Genomics Robert Gundersen, Chair of Molecular & Biomedical Sciences Edward Bernard, Laboratory Coordinator and Lecturer Sarah Harlan-Haughey, Assistant Professor of English and Honors ABSTRACT The yeast Saccharomyces cerevisiae uses a GPCR to direct the pheromone response pathway. Haploid yeast detect and respond to pheromone gradients produced by the opposite mating type to find a mating partner. At a high dose of pheromone, yeast will form a short, focused mating projection in order to mate with yeast that are close by. At lower doses of pheromone, the yeast form a broader projection which grows towards the source of pheromone.
    [Show full text]
  • Rho Activation of Mdia Formins Is Modulated by an Interaction with Inverted Formin 2 (INF2)
    Rho activation of mDia formins is modulated by an interaction with inverted formin 2 (INF2) Hua Suna,b,c, Johannes S. Schlondorffb,c, Elizabeth J. Brownc,d, Henry N. Higgse, and Martin R. Pollakb,c,1 aNephrology Division, Department of Medicine, Shanghai Children’s Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai 200127, China; bNephrology Division, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215; cDepartment of Medicine, Harvard Medical School, Boston, MA 02115; dDivision of Nephrology, Department of Medicine, Children’s Hospital, Boston, MA 02115; and eDepartment of Biochemistry, Dartmouth Medical School, Hanover, NH 03755 Edited by Christine E. Seidman, Harvard Medical School, Boston, MA, and approved December 30, 2010 (received for review November 12, 2010) Inverted formin 2 (INF2) encodes a member of the diaphanous glomerular slit diaphragm (11–13). The importance of the actin subfamily of formin proteins. Mutations in INF2 cause human cytoskeleton in maintaining the glomerular filtration barrier is kidney disease characterized by focal and segmental glomerulo- supported by the fact that mutations in α-actinin-4, an actin cross- sclerosis. Disease-causing mutations occur only in the diaphanous linking protein, cause a similar form of autosomal-dominant FSGS inhibitory domain (DID), suggesting specific roles for this domain in (14). Numerous lines of evidence support the notion that podo- the pathogenesis of disease. In a yeast two-hybrid screen, we cytes are highly sensitive to perturbations in their actin cytoskel- identified the diaphanous autoregulatory domains (DADs) of the eton (15). Consistent with this, FSGS-associated mutant forms of mammalian diaphanous-related formins (mDias) mDia1, mDia2, INF2 induce distinct patterns of actin polymerization in cultured and mDia 3 as INF2_DID-interacting partners.
    [Show full text]
  • Cytoskeleton: Formins Induce Nuclear Actin Assembly
    RESEARCH HIGHLIGHTS Nature Reviews Molecular Cell Biology | AOP, published online 24 April 2013; doi:10.1038/nrm3580 CYTOSKELETON nuclear export signal (NES-Dia1ct)) that formins drive actin assembly in the or constitutively active MAL. nucleus in response to serum. Moreover, they found that nuclear So, can MAL–SRF activity be induced Formins induce nuclear actin polymerization was required for upon nuclear mDia activation? Dia1ct-driven SRF activity, as Dia1ct To activate endogenous formins in actin assembly did not induce SRF activity when an the nucleus, the authors used an actin mutant that cannot polymerize optogenetic tool, whereby mDia Formins promote the assembly of actin was overexpressed in the nucleus. autoinhibition is released by the filaments in the cytoplasm. This leads Interestingly, only nuclear Dia1ct but not photoactivation of a diaphanous formins drive to the release of MAL (megakaryocytic cytoplasmic NES-Dia1ct could prevent autoregulatory domain. Indeed, acute leukaemia; also known as MRTF) the sequestration of MAL by nuclear repeated illumination of cells, and actin assembly from monomeric G-actin and the G-actin, which suggests that nuclear thus mDia activation, resulted in the in the nucleus accumulation of this cofactor, which actin polymerization releases MAL from reversible assembly of nuclear actin stimulates serum response factor G-actin. Moreover, cells expressing a filaments, MAL nuclear accumulation (SRF)-dependent expression of dominant-negative mDia mutant that and SRF activity. cytoskeletal target genes, in the localizes exclusively to the nucleus Together, these results show that nucleus. Although diaphanous-related exhibited decreased serum-induced the assembly of dynamic nuclear formins (mDia) have been detected in SRF activity compared with control cells, actin networks in response to serum is the nucleus, it was unclear whether they suggesting that nuclear mDia is required dependent on nuclear mDia activation.
    [Show full text]
  • The Formin FMNL3 Is a Cytoskeletal Regulator of Angiogenesis
    Dartmouth College Dartmouth Digital Commons Dartmouth Scholarship Faculty Work 2012 The Formin FMNL3 is a Cytoskeletal Regulator of Angiogenesis Clare Hetheridge University of Bristol Alice N. Scott University of Bristol Rajeeb K. Swain Birmingham University John W. Copeland University of Ottawa Henry N. Higgs Dartmouth College Follow this and additional works at: https://digitalcommons.dartmouth.edu/facoa Part of the Medical Biochemistry Commons Dartmouth Digital Commons Citation Hetheridge, Clare; Scott, Alice N.; Swain, Rajeeb K.; Copeland, John W.; and Higgs, Henry N., "The Formin FMNL3 is a Cytoskeletal Regulator of Angiogenesis" (2012). Dartmouth Scholarship. 1731. https://digitalcommons.dartmouth.edu/facoa/1731 This Article is brought to you for free and open access by the Faculty Work at Dartmouth Digital Commons. It has been accepted for inclusion in Dartmouth Scholarship by an authorized administrator of Dartmouth Digital Commons. For more information, please contact [email protected]. 1420 Research Article The formin FMNL3 is a cytoskeletal regulator of angiogenesis Clare Hetheridge1, Alice N. Scott1, Rajeeb K. Swain2, John W. Copeland3, Henry N. Higgs4, Roy Bicknell2 and Harry Mellor1,* 1School of Biochemistry, Medical Sciences Building, University Walk, University of Bristol, Bristol, BS8 1TD, UK 2Institute for Biomedical Research, Birmingham University Medical School, Vincent Drive, Birmingham, B15 2TT, UK 3University of Ottawa, Department of Cellular and Molecular Medicine, Room 3206, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada 4Dartmouth Medical School, Department of Biochemistry, Room 413, 7200 Vail Building, Hanover, NH 03755-3844, USA *Author for correspondence ([email protected]) Accepted 28 September 2011 Journal of Cell Science 125, 1420–1428 ß 2012.
    [Show full text]
  • The Formin Homology Protein Mdia1 Regulates Dynamics of Microtubules and Their Effect on Focal Adhesion Growth
    - 1 - The formin homology protein mDia1 regulates dynamics of microtubules and their effect on focal adhesion growth Christoph Ballestrem,* Natalia Schiefermeier,*ƒ Julia Zonis,* Michael Shtutman,* Zvi Kam,* Shuh Narumiya, Arthur S. Alberts, ⁄ and Alexander D. Bershadsky* *Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot 76100, Israel; Department of Pharmacology, Kyoto University Faculty of Medicine, Kyoto, Japan; ⁄Van Andel Research Institute, Grand Rapids, MI, USA. ƒThis author made significant contribution to this paper Address correspondence to: Alexander Bershadsky Department of Molecular Cell Biology The Weizmann Institute of Science P.O. Box 26, Rehovot 76100, Israel Tel.: 972-8-9342884 Fax: 972-8-9344125 E-mail: [email protected] Total characters: 59107 Running Title: mDia1 regulates dynamics of microtubules Keywords: mDia, formin homology protein, microtubule, focal adhesion, actin - 2 - Abstract The formin homology protein, mDia1, is a major effector of Rho controlling, together with the Rho-kinase (ROCK), the formation of focal adhesions and stress fibers. Here we show that a constitutively active form of mDia1 (mDia1∆N3) affects the dynamics of microtubules at three stages of their life. We found that in cells expressing mDia1∆N3, (1) the growth rate at the microtubule plus-end decreased by half, (2) the rates of microtubule plus-end growth and shortening at the cell periphery decreased while the frequency of catastrophes and rescue events remained unchanged, and (3) mDia1∆N3 expression in cytoplasts without centrosome stabilized free microtubule minus-ends. This stabilization required the activity of another Rho target, ROCK. Interestingly, mDia1∆N3 as well as endogenous mDia1, localized at the centrosome.
    [Show full text]
  • Non Diaphanous Formin Delphilin Acts As a Barbed End Capping Protein
    bioRxiv preprint doi: https://doi.org/10.1101/093104; this version posted December 11, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Non Diaphanous Formin Delphilin Acts as a Barbed End Capping Protein Priyanka Dutta and Sankar Maiti* Department of Biological Sciences Indian Institute of Science Education and Research-Kolkata Mohanpur - 741246, Nadia, West Bengal. *correspondence: [email protected] Key Words: Formin, Delphilin, Expression, Actin and Barbed end capping. bioRxiv preprint doi: https://doi.org/10.1101/093104; this version posted December 11, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. ABSTRACT: Formins are important for actin polymerization. Delphilin is a unique formin having PDZ domains and FH1, FH2 domains at its N and C terminus respectively. In this study we observed that Delphilin binds to actin filaments, and have negligible actin filament polymerizing activity. Delphilin inhibits actin filament elongation like barbed end capping protein CapZ. In vitro, Delphilin stabilized actin filaments by inhibiting actin filament depolymerisation. Therefore, our study demonstrates Delphilin as an actin-filament capping protein. INTRODUCTION: Regulated actin dynamics is essential for any organism’s survival. Formins are essential for regulation of actin dynamics. Formins play vital roles as they are key actin nucleator in formation of actin filament structure important for cell functioning.. Formins are multi domain proteins, ubiquitously expressed in eukaryotes. Formins are characterized by formin homology-2 (FH2) and formin homology-1 (FH1) domain respectively [1].
    [Show full text]
  • Science-Signaling-Breakthrough.Pdf
    ` 2013: Signaling Breakthroughs of the Year Jason D. Berndt and Nancy R. Gough (7 January 2014) Science Signaling 7 (307), eg1. [DOI: 10.1126/scisignal.2005013] The following resources related to this article are available online at http://stke.sciencemag.org. This information is current as of 1 February 2014. Article Tools Visit the online version of this article to access the personalization and article tools: http://stke.sciencemag.org/cgi/content/full/sigtrans;7/307/eg1 References This article cites 37 articles, 14 of which can be accessed for free: http://stke.sciencemag.org/cgi/content/full/sigtrans;7/307/eg1#otherarticles Glossary Look up definitions for abbreviations and terms found in this article: http://stke.sciencemag.org/glossary/ Permissions Obtain information about reproducing this article: Downloaded from http://www.sciencemag.org/about/permissions.dtl stke.sciencemag.org on February 1, 2014 Science Signaling (ISSN 1937-9145) is published weekly, except the last week in December, by the American Association for the Advancement of Science, 1200 New York Avenue, NW, Washington, DC 20005. Copyright 2008 by the American Association for the Advancement of Science; all rights reserved. EDITORIAL GUIDE CELL BIOLOGY not only provides a molecular mechanism by which stress hormone signaling, and thus 2013: Signaling Breakthroughs of the Year mood and disease resistance, changes with the circadian cycle, it also is one of only a Jason D. Berndt1* and Nancy R. Gough2* few examples of neurotransmitter switching in adult neurons. The editorial staff and distinguished scientists in the fi eld of cell signaling nominat- It is well known that cells in the nervous ed diverse research as advances for 2013.
    [Show full text]
  • Nuclear Actin Filaments in DNA Repair Dynamics
    REVIEW ARTICLE https://doi.org/10.1038/s41556-019-0379-1 Nuclear actin filaments in DNA repair dynamics Christopher Patrick Caridi1, Matthias Plessner2,3, Robert Grosse 2,3 and Irene Chiolo 1* Recent development of innovative tools for live imaging of actin filaments (F-actin) enabled the detection of surprising nuclear structures responding to various stimuli, challenging previous models that actin is substantially monomeric in the nucleus. We review these discoveries, focusing on double-strand break (DSB) repair responses. These studies revealed a remarkable network of nuclear filaments and regulatory mechanisms coordinating chromatin dynamics with repair progression and led to a paradigm shift by uncovering the directed movement of repair sites. ctin filaments are major components of the cytoskeleton, G-actin release from the myocardin-related transcription factor responsible for cell movement and adhesion, along with (MRTF-A), MTRF-A translocation to the nucleus, and transcrip- protein and RNA transport via myosin motors1–3. F-actin tional co-activation of the serum response factor (SRF)8,22,23. Similar A 10 responds dynamically to a variety of stimuli through actin remod- MRTF-A regulation occurs during cell spreading , although here ellers (e.g., actin nucleators, bundling components, crosslinking filaments are shorter and long lasting, and their formation requires proteins, and disassembly factors)1,4 (Fig. 1). The three major classes a functional LINC (linker of nucleoskeleton and cytoskeleton) com- of actin nucleators are the Arp2/3 complex, formins, and Spire- plex10. Intriguingly, MRTF-A activity also depends on its association family components, each characterized by distinct structural prop- with the F-actin crosslinking component Filamin-A24.
    [Show full text]
  • The FH2 Domain of Formin Proteins Is Critical for Platelet Cytoskeletal Dynamics
    bioRxiv preprint doi: https://doi.org/10.1101/589861; this version posted March 26, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. The FH2 domain of formin proteins is critical for platelet cytoskeletal dynamics Hannah L.H. Greena,b,d, Malou Zuidscherwoudea,c,d, Steven G. Thomasa,c aInstitute of Cardiovascular Sciences, University of Birmingham, Edgbaston, Birmingham, UK bCurrent Address: School of Cardiovascular Medicine & Sciences, BHF Centre of Research Excellence, King's College London, London, United Kingdom cCentre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK dThese authors contributed equally. Key Points •• Inhibition of FH2 domains blocks platelet spreading and disrupts actin and microtubule organisation • Inhibition of FH2 domains causes a reduction in resting platelet size but not by microtubule coil depolymerisation • FH2 domains play a role in the post-translational modification of microtubules Abstract Reorganisation of the actin cytoskeleton is required for proper functioning of platelets following activation in response to vascular damage. Formins are a family of proteins which regulate actin polymerisation and cytoskeletal organisation. Several formin protein are expressed in platelets and so we used an inhibitor of formin mediated actin polymerisation (SMIFH2) to uncover the role of these proteins in platelet spreading. Pre-treatment with SMIFH2 completely blocks platelet spreading in both mouse and human platelets through effects on the organisation and dynamics of actin and microtubules.
    [Show full text]