scholarly journals Photosynthesis-dependent Ca2+influx and functional diversity between phospholipases in the formation of cell polarity in migrating cells of red algae

2009 ◽  
Vol 4 (9) ◽  
pp. 911-913 ◽  
Author(s):  
Koji Mikami ◽  
Lin Li ◽  
Megumu Takahashi ◽  
Naotsune Saga
Keyword(s):  
Cell Polarity ◽  
Functional Diversity ◽  
Red Algae ◽  
Migrating Cells

scholarly journals Do migrating cells need a nucleus?

2018 ◽  
Vol 217 (3) ◽  
pp. 799-801 ◽  
Author(s):  
Rhoda J. Hawkins
Keyword(s):  
Cell Polarity ◽  
Three Dimensions ◽  
Mechanical Responses ◽  
Cell Biol ◽  
And Migration ◽  
Migrating Cells

How the nucleus affects cell polarity and migration is unclear. In this issue, Graham et al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201706097) show that enucleated cells polarize and migrate in two but not three dimensions and propose that the nucleus is a necessary component of the molecular clutch regulating normal mechanical responses.

scholarly journals Positive feedback between Cdc42 activity and H+ efflux by the Na-H exchanger NHE1 for polarity of migrating cells

2007 ◽  
Vol 179 (3) ◽  
pp. 403-410 ◽  
Author(s):  
Christian Frantz ◽  
Anastasios Karydis ◽  
Perihan Nalbant ◽  
Klaus M. Hahn ◽  
Diane L. Barber
Keyword(s):  
Cell Polarity ◽  
Positive Feedback ◽  
Eukaryotic Cell ◽  
Feedback Signal ◽  
Nucleotide Exchange ◽  
Spatial Cues ◽  
Membrane Recruitment ◽  
Nucleotide Exchange Factor ◽  
Guanosine Triphosphatase ◽  
Migrating Cells

A fundamental feature of cell polarity in response to spatial cues is asymmetric amplification of molecules generated by positive feedback signaling. We report a positive feedback loop between the guanosine triphosphatase Cdc42, a central determinant in eukaryotic cell polarity, and H+ efflux by Na-H+ exchanger 1 (NHE1), which is necessary at the front of migrating cells for polarity and directional motility. In response to migratory cues, Cdc42 is not activated in fibroblasts expressing a mutant NHE1 that lacks H+ efflux, and wild-type NHE1 is not activated in fibroblasts expressing mutationally inactive Cdc42-N17. H+ efflux by NHE1 is not necessary for release of Cdc42–guanosine diphosphate (GDP) from Rho GDP dissociation inhibitor or for the membrane recruitment of Cdc42 but is required for GTP binding by Cdc42 catalyzed by a guanine nucleotide exchange factor (GEF). Data indicate that GEF binding to phosphotidylinositol 4,5–bisphosphate is pH dependent, suggesting a mechanism for how H+ efflux by NHE1 promotes Cdc42 activity to generate a positive feedback signal necessary for polarity in migrating cells.

scholarly journals Multiple roles of syndecan-4 during myoblast migration

2021 ◽  
Author(s):  
Dániel Becsky
Keyword(s):  
Skeletal Muscle ◽  
Stem Cells ◽  
Cell Migration ◽  
Embryonic Development ◽  
Cell Polarity ◽  
Focal Adhesion ◽  
Muscle Disease ◽  
Satellite Stem Cells ◽  
Migrating Cells

Background and purpose: Cell migration is one of the cornerstones of regeneration processes, as it is necessary for wound healing, and also required for embryonic development, immune system activation, or tumor metastasis formation. Skeletal muscle has a special, advanced dynamism that allows it to adapt to various impacts and recover successfully after an injury, exercise, or muscle disease. Satellite stem cells are activated by local damage during muscle regeneration, and after asymmetric division, myoblasts (i.e., activated satellite cells) migrate to the site of injury, differentiate, and fuse to form muscle fibers. Migration of the cells requires cellular polarization, the creation of leading and trailing edges, as well as the proper orientation and positioning of organelles inside the cell. Efficient migration also requires the presence of an asymmetrical front-to-rear calcium (Ca2+) gradient to regulate focal adhesion assembly and actomyosin contractility. The transmembrane proteoglycan syndecan-4 (SDC4), which is one of the cell surface markers of resting and activated satellite stem cells, is involved in the formation of focal adhesions. Furthermore, SDC4 plays a variety of roles in signal transduction processes, including controlling the function of the small GTPase Rac1 by binding to and inhibiting the activity of T-lymphoma invasion and metastasis-1 (Tiam1), a guanine nucleotide exchange factor for Rac1 (Ras-related C3 botulinum toxin substrate 1) GTPase. Cell migration also requires Rac1-mediated actin remodeling. SDC4 knockout mice are unable to regenerate damaged muscle; however, its underlying precise mechanism is unclear; therefore, our aim was to analyze the role of SDC4 in myoblast migration. Experimental approaches: To achieve SDC4 knockdown, C2C12 murine myoblast cells were transfected stably with plasmids expressing short hairpin RNAs (shRNAs) specific for mouse SDC4 (shSDC4#1 and shSDC4#2) or a scrambled target sequence. To study cell migration, time-lapse images were captured at 37 °C and 5% CO2 using a high-content imaging system for single-cell tracking or wound scratch assay was performed. To evaluate the movement of the single cells, the cell nuclei were tracked with ImageJ and CellTracker software. Super-resolution direct stochastic optical reconstruction microscopy (dSTORM) measurements were performed for the nanoscale analysis of the lamellipodial actin network of the migrating cells. To study the intracellular Ca2+ level, Fluo-4 and Fura Red indicators were applied. Immunofluorescence cytochemistry was performed to analyze the distribution of SDC4, Tiam1, centrosomes, FAK (focal adhesion kinase) or GM130 (anti- Golgi matrix protein of 130 kDa) followed by wide-field fluorescence or confocal microscopy. Image analysis was performed with ImageJ. Rac1 was inhibited by NSC23766 treatment during the measurements (50 µM). Key results: Silencing of SDC4 disrupts the correct polarization of migrating mammalian myoblasts. SDC4 knockdown completely abolished the intracellular Ca2+ gradient, abrogated centrosome reorientation, and thus decreased cell motility, demonstrating the role of SDC4 in cell polarity. Additionally, SDC4 exhibited a polarized distribution during migration. SDC4 knockdown cells exhibited decreases in the total movement distance during migration, maximum and vectorial distances from the starting point, as well as average and maximum cell speeds. Analysis of the dSTORM images of SDC4 knockdown cells revealed nanoscale changes in the actin cytoskeletal architecture, such as decreases in the numbers of branches and individual branch lengths in the lamellipodia of the migrating cells. The Rac1 inhibitor NSC23766 did not restore the migration capacity of SDC4 silenced cells; in fact, it reduced it further. SDC4 knockdown decreased the directional persistence of migration, abrogated the polarized, asymmetric distribution of Tiam1, and reduced the total Tiam1 level of the cells. Conclusion: According to our results, SDC4 affects the migration of C2C12 myoblasts and modulates cell polarity by influencing centrosome positioning, intracellular Ca2+ and Tiam1 distribution. These findings may promote greater understanding the essential role of SDC4 in the embryonic development and postnatal regeneration of skeletal muscle. Given the ubiquitous expression and crucial role of SDC4 in cell migration, we conclude that our findings can facilitate understanding the general role of SDC4 during cell migration.

scholarly journals The Rho-mDia1 Pathway Regulates Cell Polarity and Focal Adhesion Turnover in Migrating Cells through Mobilizing Apc and c-Src

2006 ◽  
Vol 26 (18) ◽  
pp. 6844-6858 ◽  
Author(s):  
Norikazu Yamana ◽  
Yoshiki Arakawa ◽  
Tomohiro Nishino ◽  
Kazuo Kurokawa ◽  
Masahiro Tanji ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Cell Polarity ◽  
Rho Gtpases ◽  
Actin Filaments ◽  
Focal Adhesions ◽  
Cell Polarization ◽  
C6 Glioma Cells ◽  
Directed Cell Migration ◽  
Sites Of Action ◽  
Migrating Cells

ABSTRACT Directed cell migration requires cell polarization and adhesion turnover, in which the actin cytoskeleton and microtubules work critically. The Rho GTPases induce specific types of actin cytoskeleton and regulate microtubule dynamics. In migrating cells, Cdc42 regulates cell polarity and Rac works in membrane protrusion. However, the role of Rho in migration is little known. Rho acts on two major effectors, ROCK and mDia1, among which mDia1 produces straight actin filaments and aligns microtubules. Here we depleted mDia1 by RNA interference and found that mDia1 depletion impaired directed migration of rat C6 glioma cells by inhibiting both cell polarization and adhesion turnover. Apc and active Cdc42, which work together for cell polarization, localized in the front of migrating cells, while active c-Src, which regulates adhesion turnover, localized in focal adhesions. mDia1 depletion impaired localization of these molecules at their respective sites. Conversely, expression of active mDia1 facilitated microtubule-dependent accumulation of Apc and active Cdc42 in the polar ends of the cells and actin-dependent recruitment of c-Src in adhesions. Thus, the Rho-mDia1 pathway regulates polarization and adhesion turnover by aligning microtubules and actin filaments and delivering Apc/Cdc42 and c-Src to their respective sites of action.

scholarly journals Actin Retrograde Flows Stabilize Cell Polarity by Mechano-Chemical Feedback Loops in Migrating Cells

2016 ◽  
Vol 110 (3) ◽  
pp. 512a
Author(s):  
Stefan Wieser ◽  
Verena Ruprecht ◽  
Monika Ritsch-Marte ◽  
Carl-Philipp Heisenberg ◽  
Matthieu Piel ◽  
...  
Keyword(s):  
Cell Polarity ◽  
Feedback Loops ◽  
Migrating Cells

scholarly journals The tumor suppressor Lgl1 regulates NMII-A cellular distribution and focal adhesion morphology to optimize cell migration

2012 ◽  
Vol 23 (4) ◽  
pp. 591-601 ◽  
Author(s):  
Inbal Dahan ◽  
Ahuv Yearim ◽  
Yarin Touboul ◽  
Shoshana Ravid
Keyword(s):  
Tumor Suppressor ◽  
Cell Polarity ◽  
Focal Adhesion ◽  
Cellular Localization ◽  
Focal Adhesions ◽  
Leading Edge ◽  
Membrane Dynamics ◽  
Migrating Cells

The Drosophila tumor suppressor Lethal (2) giant larvae (Lgl) regulates the apical–basal polarity in epithelia and asymmetric cell division. However, little is known about the role of Lgl in cell polarity in migrating cells. In this study we show direct physiological interactions between the mammalian homologue of Lgl (Lgl1) and the nonmuscle myosin II isoform A (NMII-A). We demonstrate that Lgl1 and NMII-A form a complex in vivo and provide data that Lgl1 inhibits NMII-A filament assembly in vitro. Furthermore, depletion of Lgl1 results in the unexpected presence of NMII-A in the cell leading edge, a region that is not usually occupied by this protein, suggesting that Lgl1 regulates the cellular localization of NMII-A. Finally, we show that depletion of Lgl1 affects the size and number of focal adhesions, as well as cell polarity, membrane dynamics, and the rate of migrating cells. Collectively these findings indicate that Lgl1 regulates the polarity of migrating cells by controlling the assembly state of NMII-A, its cellular localization, and focal adhesion assembly.

Antitumor and antifungal activities from red algae Bostrychia radicans and B. tenella (Rhodophyta)

Planta Medica ◽  
2008 ◽  
Vol 74 (09) ◽  
Author(s):  
ALL de Oliveira ◽  
R de Felício ◽  
LV Costa-Lotufo ◽  
MO de Moraes ◽  
C do Ó Pessoa ◽  
...  
Keyword(s):  
Red Algae ◽  
Antifungal Activities

Bioactive chemical constituents from the Formosan red algae Laurencia tristicha

Planta Medica ◽  
2016 ◽  
Vol 81 (S 01) ◽  
pp. S1-S381
Author(s):  
JY Chen ◽  
CY Huang ◽  
JH Sheu
Keyword(s):  
Red Algae ◽  
Chemical Constituents
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