scholarly journals MARK3-mediated phosphorylation of ARHGEF2 couples microtubules to the actin cytoskeleton to establish cell polarity

2017 ◽  
Vol 10 (503) ◽  
pp. eaan3286 ◽  
Author(s):  
María-José Sandí ◽  
Christopher B. Marshall ◽  
Marc Balan ◽  
Étienne Coyaud ◽  
Ming Zhou ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Cell Polarity

scholarly journals High Rates of Actin Filament Turnover in Budding Yeast and Roles for Actin in Establishment and Maintenance of Cell Polarity Revealed Using the Actin Inhibitor Latrunculin-A

1997 ◽  
Vol 137 (2) ◽  
pp. 399-416 ◽  
Author(s):  
Kathryn R. Ayscough ◽  
Joel Stryker ◽  
Navin Pokala ◽  
Miranda Sanders ◽  
Phil Crews ◽  
...  
Keyword(s):  
Cell Surface ◽  
Actin Cytoskeleton ◽  
Cell Polarity ◽  
Actin Filaments ◽  
Three Dimensional ◽  
Surface Growth ◽  
Interacting Protein ◽  
Capping Protein ◽  
Latrunculin A

We report that the actin assembly inhibitor latrunculin-A (LAT-A) causes complete disruption of the yeast actin cytoskeleton within 2–5 min, suggesting that although yeast are nonmotile, their actin filaments undergo rapid cycles of assembly and disassembly in vivo. Differences in the LAT-A sensitivities of strains carrying mutations in components of the actin cytoskeleton suggest that tropomyosin, fimbrin, capping protein, Sla2p, and Srv2p act to increase actin cytoskeleton stability, while End3p and Sla1p act to decrease stability. Identification of three LAT-A resistant actin mutants demonstrated that in vivo effects of LAT-A are due specifically to impairment of actin function and implicated a region on the three-dimensional actin structure as the LAT-A binding site. LAT-A was used to determine which of 19 different proteins implicated in cell polarity development require actin to achieve polarized localization. Results show that at least two molecular pathways, one actindependent and the other actin-independent, underlie polarity development. The actin-dependent pathway localizes secretory vesicles and a putative vesicle docking complex to sites of cell surface growth, providing an explanation for the dependence of polarized cell surface growth on actin function. Unexpectedly, several proteins that function with actin during cell polarity development, including an unconventional myosin (Myo2p), calmodulin, and an actin-interacting protein (Bud6/Aip3p), achieved polarized localization by an actin-independent pathway, revealing interdependence among cell polarity pathways. Finally, transient actin depolymerization caused many cells to abandon one bud site or mating projection and to initiate growth at a second site. Thus, actin filaments are also required for maintenance of an axis of cell polarity.

scholarly journals Mechanochemical Control of Symmetry Breaking in the Caenorhabditis elegans Zygote

2021 ◽  
Vol 8 ◽  
Author(s):  
Wan Jun Gan ◽  
Fumio Motegi
Keyword(s):  
Caenorhabditis Elegans ◽  
Symmetry Breaking ◽  
Actin Cytoskeleton ◽  
Cell Polarity ◽  
Break Symmetry ◽  
Cell Cortex ◽  
Aurora A Kinase ◽  
Advective Flow ◽  
Polar State ◽  
Cellular Components

Cell polarity is the asymmetric organization of cellular components along defined axes. A key requirement for polarization is the ability of the cell to break symmetry and achieve a spatially biased organization. Despite different triggering cues in various systems, symmetry breaking (SB) usually relies on mechanochemical modulation of the actin cytoskeleton, which allows for advected movement and reorganization of cellular components. Here, the mechanisms underlying SB in Caenorhabditis elegans zygote, one of the most popular models to study cell polarity, are reviewed. A zygote initiates SB through the centrosome, which modulates mechanics of the cell cortex to establish advective flow of cortical proteins including the actin cytoskeleton and partitioning defective (PAR) proteins. The chemical signaling underlying centrosomal control of the Aurora A kinase–mediated cascade to convert the organization of the contractile actomyosin network from an apolar to polar state is also discussed.

scholarly journals Cell Cycle Progression and Cell Polarity Require Sphingolipid Biosynthesis in Aspergillus nidulans

2001 ◽  
Vol 21 (18) ◽  
pp. 6198-6209 ◽  
Author(s):  
Jijun Cheng ◽  
Tae-Sik Park ◽  
Anthony S. Fischl ◽  
Xiang S. Ye
Keyword(s):  
Cell Cycle ◽  
Actin Cytoskeleton ◽  
Aspergillus Nidulans ◽  
Cell Polarity ◽  
Cell Cycle Progression ◽  
Polarized Growth ◽  
Serine Palmitoyltransferase ◽  
Cycle Progression ◽  
Marked Accumulation ◽  
Sphingolipid Biosynthesis

ABSTRACT Sphingolipids are major components of the plasma membrane of eukaryotic cells and were once thought of merely as structural components of the membrane. We have investigated effects of inhibiting sphingolipid biosynthesis, both in germinating spores and growing hyphae of Aspergillus nidulans. In germinating spores, genetic or pharmacological inactivation of inositol phosphorylceramide (IPC) synthase arrests the cell cycle in G1 and also prevents polarized growth during spore germination. However, inactivation of IPC synthase not only eliminates sphingolipid biosynthesis but also leads to a marked accumulation of ceramide, its upstream intermediate. We therefore inactivated serine palmitoyltransferase, the first enzyme in the sphingolipid biosynthesis pathway, to determine effects of inhibiting sphingolipid biosynthesis without an accumulation of ceramide. This inactivation also prevented polarized growth but did not affect nuclear division of germinating spores. To see if sphingolipid biosynthesis is required to maintain polarized growth, and not just to establish polarity, we inhibited sphingolipid biosynthesis in cells in which polarity was already established. This inhibition rapidly abolished normal cell polarity and promoted cell tip branching, which normally never occurs. Cell tip branching was closely associated with dramatic changes in the normally highly polarized actin cytoskeleton and found to be dependent on actin function. The results indicate that sphingolipids are essential for the establishment and maintenance of cell polarity via control of the actin cytoskeleton and that accumulation of ceramide is likely responsible for arresting the cell cycle in G1.

scholarly journals Wdpcp, a PCP Protein Required for Ciliogenesis, Regulates Directional Cell Migration and Cell Polarity by Direct Modulation of the Actin Cytoskeleton

PLoS Biology ◽  
2013 ◽  
Vol 11 (11) ◽  
pp. e1001720 ◽  
Author(s):  
Cheng Cui ◽  
Bishwanath Chatterjee ◽  
Thomas P. Lozito ◽  
Zhen Zhang ◽  
Richard J. Francis ◽  
...  
Keyword(s):  
Cell Migration ◽  
Actin Cytoskeleton ◽  
Cell Polarity ◽  
Direct Modulation ◽  
Directional Cell Migration

scholarly journals A ubiquitin C-terminal hydrolase is required to maintain osmotic balance and execute actin-dependent processes in the early C. elegansembryo

2002 ◽  
Vol 115 (11) ◽  
pp. 2293-2302
Author(s):  
Susanne Kaitna ◽  
Heinke Schnabel ◽  
Ralf Schnabel ◽  
Anthony A. Hyman ◽  
Michael Glotzer
Keyword(s):  
Caenorhabditis Elegans ◽  
Actin Cytoskeleton ◽  
Cell Polarity ◽  
Maternal Effect ◽  
Embryonic Lethality ◽  
Cleavage Furrow ◽  
Osmotic Regulation ◽  
Osmotic Balance ◽  
Dependent Processes

In the early Caenorhabditis elegans embryo, establishment of cell polarity and cytokinesis are both dependent upon reorganization of the actin cytoskeleton. Mutations in the cyk-3 gene cause maternal effect embryonic lethality. Embryos produced by homozygous cyk-3 mutant animals become multinucleate. We have further analyzed the cyk-3mutant phenotype and have found that cyk-3 mutant embryos fail to properly polarize the actin cytoskeleton and fail to segregate germline determinants. In addition, they fail to assemble an intact cleavage furrow. However, we have found that cyk-3 mutant embryos are intrinsically defective in osmotic regulation and that the cytokinesis defects can be partially rescued by providing osmotic support. The cyk-3 gene has been identified and found to encode a ubiquitin C-terminal hydrolase that is active against model substrates. These data indicate that the deubiquitination of certain substrates by CYK-3 is crucial for cellular osmoregulation. Defects in osmoregulation appear to indirectly affect actin-dependent processes.

scholarly journals Regulating polarity by directing traffic: Cdc42 prevents adherens junctions from Crumblin' aPart

2008 ◽  
Vol 183 (6) ◽  
pp. 971-974 ◽  
Author(s):  
Mara C. Duncan ◽  
Mark Peifer
Keyword(s):  
Cell Adhesion ◽  
Actin Cytoskeleton ◽  
Cell Polarity ◽  
Adherens Junctions ◽  
Vesicular Trafficking ◽  
Cell Junction ◽  
Par Proteins ◽  
Cell Biol ◽  
Embryonic Morphogenesis ◽  
Junction Proteins

The GTPase Cdc42 was among the original genes identified with roles in cell polarity, and interest in its cellular roles from yeast to humans remains high. Cdc42 is a well-known regulator of the actin cytoskeleton, but also plays important roles in vesicular trafficking. In this issue, Harris and Tepass (Harris, K.P, and U. Tepass. 2008. J. Cell. Biol. 183:1129–1143) provide new insights into how Cdc42 and Par proteins work together to modulate cell adhesion and polarity during embryonic morphogenesis by regulating the traffic of key cell junction proteins.

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