scholarly journals A widely conserved bacterial cytoskeletal component influences unique helical shape and motility of the spirocheteLeptospira biflexa

2018 ◽  
Vol 108 (1) ◽  
pp. 77-89 ◽  
Author(s):  
Katrina M. Jackson ◽  
Cindi Schwartz ◽  
Jenny Wachter ◽  
Patricia A. Rosa ◽  
Philip E. Stewart
Keyword(s):  
Cytoskeletal Component

scholarly journals Shape oscillations of human neutrophil leukocytes: characterization and relationship to cell motility.

1996 ◽  
Vol 199 (4) ◽  
pp. 741-747
Author(s):  
M U Ehrengruber ◽  
D A Deranleau ◽  
T D Coates
Keyword(s):  
Light Scattering ◽  
Actin Polymerization ◽  
Cellular Migration ◽  
Human Neutrophils ◽  
Filamentous Actin ◽  
Cytoskeletal Component ◽  
Morphological Polarity ◽  
Shape Oscillations ◽  
Shape Changes ◽  
Neutrophil Leukocytes

When neutrophil leukocytes are stimulated by chemotactic factors or by substratum contact, they change their shape. Shape changes are a prerequisite for cellular migration and typically involve the extrusion of thin, veil-like lamellipods and the development of morphological polarity. Stimulation also leads to changes in the neutrophil content of filamentous actin (F-actin), which is the major cytoskeletal component. Suspensions of human neutrophils stimulated with chemoattractants exhibit sinusoidal light-scattering oscillations with a period of approximately 8 s at 37 degrees C. These oscillations arise from periodic fluctuations in the cell body size caused by lamellipod extension and retraction cycles. The light-scattering oscillations are paralleled by corresponding oscillations in F-actin content. This raises the interesting possibility that cyclic actin polymerization constitutes the driving force for shape oscillations of suspended neutrophils. Similar periodic shape changes are present in neutrophils crawling on a surface, suggesting that shape oscillations are important for neutrophil motion. This review summarizes our present knowledge about shape oscillations in suspended and crawling neutrophils and discusses a possible role for these oscillations in neutrophil motility.

Myosin light chain kinase transference induces myosin light chain activation and endothelial hyperpermeability

2000 ◽  
Vol 279 (4) ◽  
pp. C1285-C1289 ◽  
Author(s):  
John H. Tinsley ◽  
Primal De Lanerolle ◽  
Emily Wilson ◽  
Weiya Ma ◽  
Sarah Y. Yuan
Keyword(s):  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Direct Result ◽  
Significant Shift ◽  
Gap Formation ◽  
Endothelial Barrier Function ◽  
Actomyosin Interaction ◽  
Cytoskeletal Component ◽  
And Function

The actomyosin complex is the major cytoskeletal component that controls cell contraction. In this study, we investigated the effects of actomyosin interaction on endothelial barrier function and gap formation. Activated myosin light chain kinase (MLCK) protein was transferred into coronary venular endothelial cell (CVEC) monolayers. Uptake of the activated protein resulted in a significant shift in myosin light chain (MLC) from an unphosphorylated to a diphosphorylated form. In addition, MLCK induced a hyperpermeability response of the monolayer as measured by albumin transendothelial flux. Microscopic examination of MLCK-treated CVECs revealed widespread gap formation in the monolayer, loss of peripheral β-catenin, and increases in actin stress fibers. Inhibition of all of the above responses by a specific MLCK inhibitor suggests they are the direct result of exogenously added MLCK. These data suggest that activation of MLCK in CVECs causes phosphorylation of MLC and contraction of CVECs, resulting in gap formation and concomitant increases in permeability. This study uses a novel technique to measure the effects of an activated kinase on both its substrate and cellular morphology and function through direct transference into endothelial cells.

scholarly journals FPC4: a new cytoskeletal component in T.brucei

Cilia ◽  
2015 ◽  
Vol 4 (S1) ◽  
Author(s):  
A Albisetti ◽  
C Florimond ◽  
A Sahin ◽  
M Eggenspieler ◽  
O Cingal ◽  
...  
Keyword(s):  
Cytoskeletal Component

scholarly journals Interactions between receptors for interleukin 2 and interleukin 4 on lines of helper T cells (HT-2) and B lymphoma cells (BCL1).

1989 ◽  
Vol 169 (2) ◽  
pp. 379-391 ◽  
Author(s):  
R Fernandez-Botran ◽  
V M Sanders ◽  
E S Vitetta
Keyword(s):  
Interleukin 2 ◽  
Interleukin 4 ◽  
Receptor Interaction ◽  
Scatchard Analysis ◽  
High Affinity ◽  
B Lymphoma Cells ◽  
Common Receptor ◽  
Binding Data ◽  
Cytoskeletal Component ◽  
And Function

IL-2 and IL-4 induce a synergistic proliferative response in HT-2 cells, suggesting that IL-2Rs and IL-4Rs may interact. The purpose of this study was to examine the effect of IL-4 on the expression and function of IL-2Rs. Preincubation of HT-2 and BCL1-3B3 cells with IL-4 for 60 min at 4 degrees C or 37 degrees C resulted in a partial decrease in the number, but not the affinity of high affinity IL-2Rs as evidenced by Scatchard analysis of binding data. The decrease in the number of high affinity receptors correlated with decreased internalization of IL-2. After preincubation with IL-4, crosslinking of 125I-IL-2 to high affinity IL-2Rs also demonstrated a approximately 50% reduction in the number of high affinity IL-2Rs. Another lymphokine, IL-1, which acts on HT-2 cells, had no measurable effect on the affinity or number of IL-2Rs. Taken together, these results indicate that IL-4 downregulates the expression of high affinity IL-2Rs on some cells. It is not known whether this occurs by a direct ligand-mediated receptor interaction, by the sharing of a common receptor subunit, or by interaction of the two receptors with another membrane molecule or cytoskeletal component.

scholarly journals Voltage-dependent Anion-selective Channels VDAC2 and VDAC3 Are Abundant Proteins in Bovine Outer Dense Fibers, a Cytoskeletal Component of the Sperm Flagellum

2004 ◽  
Vol 279 (15) ◽  
pp. 15281-15288 ◽  
Author(s):  
Klaus-Dieter Hinsch ◽  
Vito De Pinto ◽  
Viviana A. Aires ◽  
Xenia Schneider ◽  
Angela Messina ◽  
...  
Keyword(s):  
Sperm Flagellum ◽  
Voltage Dependent ◽  
Cytoskeletal Component ◽  
Outer Dense Fibers

scholarly journals Strong adhesion by regulatory T cells induces dendritic cell cytoskeletal polarization and contact-dependent lethargy

2017 ◽  
Vol 214 (2) ◽  
pp. 327-338 ◽  
Author(s):  
Jiahuan Chen ◽  
Anutosh Ganguly ◽  
Ashley D. Mucsi ◽  
Junchen Meng ◽  
Jiacong Yan ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
T Cell ◽  
Synapse Formation ◽  
Immunological Synapse ◽  
Super Resolution ◽  
Dependent Manner ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Cytoskeletal Component ◽  
Strong Adhesion

Dendritic cells are targeted by regulatory T (T reg) cells, in a manner that operates as an indirect mode of T cell suppression. In this study, using a combination of single-cell force spectroscopy and structured illumination microscopy, we analyze individual T reg cell–DC interaction events and show that T reg cells exhibit strong intrinsic adhesiveness to DCs. This increased DC adhesion reduces the ability of contacted DCs to engage other antigen-specific cells. We show that this unusually strong LFA-1–dependent adhesiveness of T reg cells is caused in part by their low calpain activities, which normally release integrin–cytoskeleton linkage, and thereby reduce adhesion. Super resolution imaging reveals that such T reg cell adhesion causes sequestration of Fascin-1, an actin-bundling protein essential for immunological synapse formation, and skews Fascin-1–dependent actin polarization in DCs toward the T reg cell adhesion zone. Although it is reversible upon T reg cell disengagement, this sequestration of essential cytoskeletal components causes a lethargic state of DCs, leading to reduced T cell priming. Our results reveal a dynamic cytoskeletal component underlying T reg cell–mediated DC suppression in a contact-dependent manner.

Protection against ethanol injury by prostaglandin in a human intestinal cell line: role of microtubules

1998 ◽  
Vol 274 (1) ◽  
pp. G111-G121 ◽  
Author(s):  
A. Banan ◽  
G. S. Smith ◽  
C. L. Rieckenberg ◽  
E. R. Kokoska ◽  
T. A. Miller
Keyword(s):  
Cell Line ◽  
Protective Action ◽  
Microtubule Assembly ◽  
Intestinal Cell ◽  
Major Protein ◽  
Cellular Viability ◽  
Intestinal Cell Line ◽  
Cytoskeletal Component ◽  
Human Intestinal Cell Line

Prostaglandins have been shown to protect the gastrointestinal (GI) epithelium from injury induced by various luminal insults independent of their known acid-inhibitory effects, a process termed “cytoprotection.” The mechanism of this protective action remains unknown. The present investigation determined the role of microtubules (a major cytoskeletal component) in GI injury induced by ethanol (EtOH) and its prevention by 16,16-dimethylprostaglandin E2(dmPGE2) using cells from a human colonic cell line known as Caco-2 cells. These cells were preincubated in Eagle’s minimum essential medium with and without dmPGE2 (2.6 μM) for 15 min and subsequently incubated in media containing 1, 2.5, 5, 7.5, and 10% EtOH. The effects on cell viability and tubulin (the major protein backbone of microtubules) were then determined. EtOH concentrations ≥2.5% extensively disrupted the microtubules as demonstrated by fragmentation, kinking, and perturbation of the microtubule organizer center. EtOH treatment also led to a significant decrease in the S2 (polymerized) fraction and an increase in the S1 (monomeric) pool of tubulin. Concomitant with these effects were marked decreases in cellular viability. DmPGE2pretreatment abolished the disruption of microtubules, significantly increased the S2 fraction of tubulin, and increased cellular viability in cultures exposed to EtOH. Furthermore, pretreatment with colchicine, an inhibitor of microtubule assembly, prevented the cytoprotective action of dmPGE2. Taxol, a microtubule stabilizing agent, mimicked the effects of dmPGE2 by also enhancing microtubule integrity and increasing cellular viability in cells exposed to EtOH. Our data indicate that organization and stabilization of microtubules may play an essential role in the mechanism of prostaglandin-induced protection.

scholarly journals Patterns of localization and cytoskeletal association of two vegetally localized RNAs, Vg1 and Xcat-2

Development ◽  
1995 ◽  
Vol 121 (1) ◽  
pp. 201-208 ◽  
Author(s):  
C. Forristall ◽  
M. Pondel ◽  
L. Chen ◽  
M.L. King
Keyword(s):  
Germ Plasm ◽  
Rna Binding ◽  
Stage Iv ◽  
Rna Localization ◽  
Insoluble Fraction ◽  
Early Embryo ◽  
Vegetal Cortex ◽  
Cytoskeletal Component ◽  
Rare Class ◽  
Mitochondrial Cloud

In Xenopus, localization of a rare class of mRNAs during oogenesis is believed to initiate pattern formation in the early embryo. We have determined the pattern of RNA localization for one of these RNAs, Xcat-2, which encodes a putative RNA-binding protein related to Drosophila nanos (Mosquera, L., Forristall, C., Zhou, Y. and King, M. L. (1993) Development 117, 377–386). Xcat-2 is exclusively localized to the mitochondrial cloud in stage I oocytes, moves with this body into the vegetal cortex during stage II and, later, partitions into islands consistent with it being a component of the germ plasm. As previously shown, Vg1 is not localized to the vegetal cortex until stage IV and distributes to all vegetal blastomeres during development. We found a direct correlation between the localized condition of these RNAs and their recovery in a detergent-insoluble fraction. We present evidence suggesting that differential RNA binding to a cytoskeletal component(s) in the vegetal cortex determines the pattern of inheritance for that RNA in the embryo.

scholarly journals Isoform-specific complementation of the yeast sac6 null mutation by human fimbrin.

1995 ◽  
Vol 15 (1) ◽  
pp. 69-75 ◽  
Author(s):  
A E Adams ◽  
W Shen ◽  
C S Lin ◽  
J Leavitt ◽  
P Matsudaira
Keyword(s):  
Cell Types ◽  
Biochemical Properties ◽  
Actin Binding ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Null Mutation ◽  
Homologous Proteins ◽  
Functional Conservation ◽  
Cytoskeletal Component

The actin cytoskeleton is a fundamental component of eukaryotic cells, with both structural and motile roles. Actin and many of the actin-binding proteins found in different cell types are highly conserved, showing considerable similarity in both primary structure and biochemical properties. To make detailed comparisons between homologous proteins, it is necessary to know whether the various proteins are functionally, as well as structurally, conserved. Fimbrin is an example of a cytoskeletal component that, as shown by sequence determinations and biochemical characterizations, is conserved between organisms as diverse as Saccharomyces cerevisiae and humans. In this study, we examined whether the human homolog can substitute for the yeast protein in vivo. We report here that two isoforms of human fimbrin, also referred to as T- and L-plastin, can both substitute in vivo for yeast fimbrin, also known as Sac6p, whereas a third isoform, I-fimbrin (or I-plastin), cannot. We demonstrate that the human T- and L-fimbrins, in addition to complementing the temperature-sensitive growth defect of the sac6 null mutant, restore both normal cytoskeletal organization and cell shape to the mutant cells. In addition, we show that human T- and L-fimbrins can complement a sporulation defect caused by the sac6 null mutation. These findings indicate that there is a high degree of functional conservation in the cytoskeleton, even between organisms as diverse as S. cerevisiae and humans.

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