scholarly journals Extracellular cell wall β(1,3)glucan is required to couple septation to actomyosin ring contraction

2013 ◽  
Vol 203 (2) ◽  
pp. 265-282 ◽  
Author(s):  
Javier Muñoz ◽  
Juan Carlos G. Cortés ◽  
Matthias Sipiczki ◽  
Mariona Ramos ◽  
José Angel Clemente-Ramos ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Animal Cells ◽  
Contractile Ring ◽  
Septum Formation ◽  
Main Cell ◽  
Primary Septum ◽  
Pulling Forces

Cytokinesis has been extensively studied in different models, but the role of the extracellular cell wall is less understood. Here we studied this process in fission yeast. The essential protein Bgs4 synthesizes the main cell wall β(1,3)glucan. We show that Bgs4-derived β(1,3)glucan is required for correct and stable actomyosin ring positioning in the cell middle, before the start of septum formation and anchorage to the cell wall. Consequently, β(1,3)glucan loss generated ring sliding, oblique positioned rings and septa, misdirected septum synthesis indicative of relaxed rings, and uncoupling between a fast ring and membrane ingression and slow septum synthesis, suggesting that cytokinesis can progress with defective septum pushing and/or ring pulling forces. Moreover, Bgs4-derived β(1,3)glucan is essential for secondary septum formation and correct primary septum completion. Therefore, our results show that extracellular β(1,3)glucan is required for cytokinesis to connect the cell wall with the plasma membrane and for contractile ring function, as proposed for the equivalent extracellular matrix in animal cells.

Plant cell wall signalling and receptor-like kinases

2017 ◽  
Vol 474 (4) ◽  
pp. 471-492 ◽  
Author(s):  
Sebastian Wolf
Keyword(s):  
Extracellular Matrix ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Plant Cell Wall ◽  
Cell Interior ◽  
Altered Expression ◽  
Extrinsic Cues ◽  
Receptor Like Kinase ◽  
Plasma Membrane Receptor

Communication between the extracellular matrix and the cell interior is essential for all organisms as intrinsic and extrinsic cues have to be integrated to co-ordinate development, growth, and behaviour. This applies in particular to plants, the growth and shape of which is governed by deposition and remodelling of the cell wall, a rigid, yet dynamic, extracellular network. It is thus generally assumed that cell wall surveillance pathways exist to monitor the state of the wall and, if needed, elicit compensatory responses such as altered expression of cell wall remodelling and biosynthesis genes. Here, I highlight recent advances in the field of cell wall signalling in plants, with emphasis on the role of plasma membrane receptor-like kinase complexes. In addition, possible roles for cell wall-mediated signalling beyond the maintenance of cell wall integrity are discussed.

scholarly journals N-Acetylglucosamine Regulates Morphogenesis and Virulence Pathways in Fungi

2019 ◽  
Vol 6 (1) ◽  
pp. 8 ◽  
Author(s):  
Kyunghun Min ◽  
Shamoon Naseem ◽  
James B. Konopka
Keyword(s):  
Cell Wall ◽  
Stress Responses ◽  
Hyphal Growth ◽  
Amino Sugar ◽  
Model Organisms ◽  
Animal Cells ◽  
Epigenetic Switch ◽  
Wide Range ◽  
Extracellular Environment

N-acetylglucosamine (GlcNAc) is being increasingly recognized for its ability to stimulate cell signaling. This amino sugar is best known as a component of cell wall peptidoglycan in bacteria, cell wall chitin in fungi and parasites, exoskeletons of arthropods, and the extracellular matrix of animal cells. In addition to these structural roles, GlcNAc is now known to stimulate morphological and stress responses in a wide range of organisms. In fungi, the model organisms Saccharomyces cerevisiae and Schizosaccharomyces pombe lack the ability to respond to GlcNAc or catabolize it, so studies with the human pathogen Candida albicans have been providing new insights into the ability of GlcNAc to stimulate cellular responses. GlcNAc potently induces C. albicans to transition from budding to filamentous hyphal growth. It also promotes an epigenetic switch from White to Opaque cells, which differ in morphology, metabolism, and virulence properties. These studies have led to new discoveries, such as the identification of the first eukaryotic GlcNAc transporter. Other results have shown that GlcNAc can induce signaling in C. albicans in two ways. One is to act as a signaling molecule independent of its catabolism, and the other is that its catabolism can cause the alkalinization of the extracellular environment, which provides an additional stimulus to form hyphae. GlcNAc also induces the expression of virulence genes in the C. albicans, indicating it can influence pathogenesis. Therefore, this review will describe the recent advances in understanding the role of GlcNAc signaling pathways in regulating C. albicans morphogenesis and virulence.

Inhibition of sperm-egg fusion in the hamster and mouse by carbohydrates

Zygote ◽  
1994 ◽  
Vol 2 (3) ◽  
pp. 253-262 ◽  
Author(s):  
Ruben H. Ponce ◽  
Umbert A. Urch ◽  
Ryuzo Yanagimachi
Keyword(s):  
Extracellular Matrix ◽  
Plasma Membrane ◽  
Zona Pellucida ◽  
Binding Proteins ◽  
Toxic Effects ◽  
Carbohydrate Binding ◽  
Dextran Sulphate ◽  
Membrane Glycoproteins ◽  
Carbohydrate Binding Proteins

SummaryAfter spermatozoa bind to and penetrate the extracellular matrix of the egg, the zona pellucida, they adhere to and fuse with the plasma membrane of the egg. Since sperm–egg fusion may involve membrane glycoproteins and/or carbohydrate binding proteins, we sought to test this hypothesis by challenging sperm–egg fusion in hamster and in mouse with added carbohydrates. In this study, a number of carbohydrate and glycoconjugates were examined for their ability to inhibit sperm–eggfusion. In the hamster, D(+)-glucosamine, D(+)-galactosamine, albumin-bovine-glucosamide and-galactosamide, fucoidan and dextran sulphate inhibited the fusion of spermatozoa with zona-free eggs. The same effects were seen in the mouse, except for the toxic effects of D(+)-galactosamine. These facts suggest a role of carbohydrate binding proteins or glycoproteins in the fertilisation process at the level of binding to and fusing with the oolemma.

The Cell's Biological Rods and Ropes

MRS Bulletin ◽  
1999 ◽  
Vol 24 (10) ◽  
pp. 27-31 ◽  
Author(s):  
David Boal
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Chemical Composition ◽  
Intermediate Filaments ◽  
Plant Cells ◽  
Cell Type ◽  
Animal Cells ◽  
Limited Variation ◽  
A Cell ◽  
Mechanical Elements

Despite a variety of shapes and sizes, the generic mechanical structure of cells is remarkably similar from one cell type to the next. All cells are bounded by a plasma membrane, a fluid sheet that controls the passage of materials into and out of the cell. Plant cells and bacteria reinforce this membrane with a cell wall, permitting the cell to operate at an elevated osmotic pressure. Simple cells, such as the bacterium shown in Figure 1a, possess a fairly homogeneous interior containing the cell's genetic blueprint and protein workhorses, but no mechanical elements. In contrast, as can be seen in Figure 1b, plant and animal cells contain internal compartments and a filamentous cytoskeleton—a network of biological ropes, cables, and poles that helps maintain the cell's shape and organize its contents.Four principal types of filaments are found in the cytoskeleton: spectrin, actin, microtubules, and a family of intermediate filaments. Not all filaments are present in all cells. The chemical composition of the filaments shows only limited variation from one cell to another, even in organisms as diverse as humans and yeasts. Membranes have a more variable composition, consisting of a bi-layer of dual-chain lipid molecules in which are embedded various proteins and frequently a moderate concentration of cholesterol. The similarity of the cell's mechanical elements in chemical composition and physical characteristics encourages us to search for universal strategies that have developed in nature for the engineering specifications of the cell. In this article, we concentrate on the cytoskeleton and its filaments.

scholarly journals Role of Cell Cycle-regulated Expression in the Localized Incorporation of Cell Wall Proteins in Yeast

2006 ◽  
Vol 17 (7) ◽  
pp. 3267-3280 ◽  
Author(s):  
Gertien J. Smits ◽  
Laura R. Schenkman ◽  
Stanley Brul ◽  
John R. Pringle ◽  
Frans M. Klis
Keyword(s):  
Cell Cycle ◽  
Cell Wall ◽  
Mechanical Damage ◽  
Cell Wall Proteins ◽  
Functional Interaction ◽  
Promoter Regions ◽  
Septum Formation ◽  
Regulated Expression ◽  
Mother Cells

The yeast cell wall is an essential organelle that protects the cell from mechanical damage and antimicrobial peptides, participates in cell recognition and adhesion, and is important for the generation and maintenance of normal cell shape. We studied the localization of three covalently bound cell wall proteins in Saccharomyces cerevisiae. Tip1p was found only in mother cells, whereas Cwp2p was incorporated in small-to-medium–sized buds. When the promoter regions of TIP1 and CWP2 (responsible for transcription in early G1and S/G2phases, respectively) were exchanged, the localization patterns of Tip1p and Cwp2p were reversed, indicating that the localization of cell wall proteins can be completely determined by the timing of transcription during the cell cycle. The third protein, Cwp1p, was incorporated into the birth scar, where it remained for several generations. However, we could not detect any role of Cwp1p in strengthening the birth scar wall or any functional interaction with the proteins that mark the birth scar pole as a potential future budding site. Promoter-exchange experiments showed that expression in S/G2phase is necessary but not sufficient for the normal localization of Cwp1p. Studies of mutants in which septum formation is perturbed indicate that the normal asymmetric localization of Cwp1p also depends on the normal timing of septum formation, composition of the septum, or both.

Structure and development of cortical microtubule arrays in plant cells

1978 ◽  
Vol 36 (2) ◽  
pp. 264-265
Author(s):  
A.R. Hardham ◽  
B.E.S. Gunning
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cortical Microtubule ◽  
Plant Cells ◽  
Original Description ◽  
Cell Cortex ◽  
Cortical Microtubules ◽  
Fundamental Part ◽  
Cellulose Component

Microtubules in the plant cell cortex are usually aligned parallel to microfibrils of cellulose that are being deposited in the cell wall, and are considered to function in guiding or orienting cellulose synthetase complexes that lie in or on the plasma membrane. The cellulose component is largely responsible for the mechanical reaction of the wall to turgor forces, thereby determining cell size and shape, and therefore the role of the cortical microtubules is a fundamental part of the overall morphogenetic process in plants. It is important to determine the structure of cortical arrays of microtubules and to learn how the cell regulates their development, neither of these aspects having been investigated adequately since the original description likened the microtubules to “hundreds of hoops around the cell”.

A pathway of plasma membrane biogenesis bypassing the Golgi apparatus during cell division in the green alga Cylindrocapsa geminella

1984 ◽  
Vol 72 (1) ◽  
pp. 89-100
Author(s):  
H.J. Sluiman
Keyword(s):  
Plasma Membrane ◽  
Cell Division ◽  
Golgi Apparatus ◽  
Cell Plate ◽  
Membrane Biogenesis ◽  
Membrane Flow ◽  
Septum Formation ◽  
Primary Septum ◽  
Rough Er ◽  
And Function

Cell division in Cylindrocapsa geminella, in particular the mode of septum membrane biogenesis, has been studied with the transmission electron microscope. Septum formation takes place in a narrow layer of cytoplasm separating post-mitotic nuclei. First, each daughter nucleus develops a wide cytoplasmic pocket (invagination) containing numerous strands of rough endoplasmic reticulum (ER). Next, a proliferation of rough ER is observed in the equatorial zone of cytoplasm, which invariably contains a small number of widely scattered microtubules. The equatorially aligned cisternae of rough ER produce smooth-membraned vesicles, interpreted as smooth ER, which subsequently coalesce to form the membranous transverse septum. Thus, primary septum formation does not follow any of the two previously known basic cytokinetic patterns in green plants (i.e. plasma membrane furrowing and cell-plate formation), but instead represents a novel type of membrane flow, which effectively bypasses the Golgi apparatus. This pathway of membrane flow has remained largely ignored in current concepts of endomembrane structure and function in eukaryotes. However, it appears to be more widespread than has previously been recognized, especially in autospore-producing green algae and in red algae during the formation of tetraspores. It may represent an evolutionary intermediate type of cell division between the supposedly primitive method of plasma membrane furrowing and the more advanced cell-plate system.

scholarly journals Role of Tropomyosin in Formin-mediated Contractile Ring Assembly in Fission Yeast

2009 ◽  
Vol 20 (8) ◽  
pp. 2160-2173 ◽  
Author(s):  
Colleen T. Skau ◽  
Erin M. Neidt ◽  
David R. Kovar
Keyword(s):  
Fission Yeast ◽  
Actin Filament ◽  
Actin Filaments ◽  
Actin Polymerization ◽  
Actin Assembly ◽  
Animal Cells ◽  
Contractile Ring ◽  
Direct Role ◽  
Ring Assembly

Like animal cells, fission yeast divides by assembling actin filaments into a contractile ring. In addition to formin Cdc12p and profilin, the single tropomyosin isoform SpTm is required for contractile ring assembly. Cdc12p nucleates actin filaments and remains processively associated with the elongating barbed end while driving the addition of profilin-actin. SpTm is thought to stabilize mature filaments, but it is not known how SpTm localizes to the contractile ring and whether SpTm plays a direct role in Cdc12p-mediated actin polymerization. Using “bulk” and single actin filament assays, we discovered that Cdc12p can recruit SpTm to actin filaments and that SpTm has diverse effects on Cdc12p-mediated actin assembly. On its own, SpTm inhibits actin filament elongation and depolymerization. However, Cdc12p completely overcomes the combined inhibition of actin nucleation and barbed end elongation by profilin and SpTm. Furthermore, SpTm increases the length of Cdc12p-nucleated actin filaments by enhancing the elongation rate twofold and by allowing them to anneal end to end. In contrast, SpTm ultimately turns off Cdc12p-mediated elongation by “trapping” Cdc12p within annealed filaments or by dissociating Cdc12p from the barbed end. Therefore, SpTm makes multiple contributions to contractile ring assembly during and after actin polymerization.

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