scholarly journals Osmophoresis - a possible mechanism for vesicle trafficking in tip-growing cells

2015 ◽  
Author(s):  
Andrei Lipchinsky
Keyword(s):  
Cell Motility ◽  
Water Potential ◽  
Water Flow ◽  
Vesicle Trafficking ◽  
Pollen Tubes ◽  
Cytoskeletal Dynamics ◽  
Growth Oscillation ◽  
Polarized Transport ◽  
Vesicle Movement

A mechanism for polarized transport of vesicles by means of osmotic propulsions is proposed and substantiated for tip-growing cells. An analysis is presented which shows that in pollen tubes the gradient of cytosolic water potential can drive vesicle movement either in the anterograde or retrograde direction, depending on the vesicle position, its radius and the phase of growth oscillation. The importance of transcellular water flow for cytoskeletal dynamics and cell motility is highlighted.

scholarly journals The microRNA-210-Stathmin1 Axis Decreases Cell Stiffness to Facilitate the Invasiveness of Colorectal Cancer Stem Cells

Cancers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1833
Author(s):  
Tsai-Tsen Liao ◽  
Wei-Chung Cheng ◽  
Chih-Yung Yang ◽  
Yin-Quan Chen ◽  
Shu-Han Su ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Stem Cells ◽  
Cancer Stem Cells ◽  
Cell Motility ◽  
Cancer Cells ◽  
Epithelial Mesenchymal Transition ◽  
Cell Stiffness ◽  
Mesenchymal Transition ◽  
Cytoskeletal Dynamics ◽  
Colorectal Cancer Stem Cells

Cell migration is critical for regional dissemination and distal metastasis of cancer cells, which remain the major causes of poor prognosis and death in patients with colorectal cancer (CRC). Although cytoskeletal dynamics and cellular deformability contribute to the migration of cancer cells and metastasis, the mechanisms governing the migratory ability of cancer stem cells (CSCs), a nongenetic source of tumor heterogeneity, are unclear. Here, we expanded colorectal CSCs (CRCSCs) as colonospheres and showed that CRCSCs exhibited higher cell motility in transwell migration assays and 3D invasion assays and greater deformability in particle tracking microrheology than did their parental CRC cells. Mechanistically, in CRCSCs, microRNA-210-3p (miR-210) targeted stathmin1 (STMN1), which is known for inducing microtubule destabilization, to decrease cell elasticity in order to facilitate cell motility without affecting the epithelial–mesenchymal transition (EMT) status. Clinically, the miR-210-STMN1 axis was activated in CRC patients with liver metastasis and correlated with a worse clinical outcome. This study elucidates a miRNA-oriented mechanism regulating the deformability of CRCSCs beyond the EMT process.

Needle water potential and soil-to-foliage flow resistance during soil drying: a comparison of Douglas-fir, western hemlock, and mountain hemlock

1985 ◽  
Vol 15 (1) ◽  
pp. 185-188 ◽  
Author(s):  
T. M. Ballard ◽  
M. G. Dosskey
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Flow ◽  
Flow Resistance ◽  
Soil Water Potential ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Soil Drying ◽  
Experimental Conditions ◽  
Needle Water Potential

Needle water potential in western and mountain hemlock falls as the soil dries, but under our experimental conditions, it remained stable in Douglas-fir. Resistance to water flow from soil to foliage is higher for the hemlocks and increases more steeply as the soil dries. These findings physically account for the observation that water uptake is reduced relatively more for the hemlocks than for Douglas-fir, as soil water potential declines.

scholarly journals Arp2/3-Branched Actin Maintains an Active Pool of GTP-RhoA and Controls RhoA Abundance

Cells ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1264
Author(s):  
Yuxing Huang ◽  
Xin Yi ◽  
Chenlu Kang ◽  
Congying Wu
Keyword(s):  
Signal Transduction ◽  
Cell Motility ◽  
Small Gtpases ◽  
Small Gtpase ◽  
Protein Abundance ◽  
Rhoa Activity ◽  
Cytoskeletal Dynamics ◽  
Active Pool ◽  
Spatiotemporal Control

Small GTPases regulate cytoskeletal dynamics, cell motility, and division under precise spatiotemporal control. Different small GTPases exhibit cross talks to exert feedback response or to act in concert during signal transduction. However, whether and how specific cytoskeletal components’ feedback to upstream signaling factors remains largely elusive. Here, we report an intriguing finding that disruption of the Arp2/3-branched actin specifically reduces RhoA activity but upregulates its total protein abundance. We further dissect the mechanisms underlying these circumstances and identify the altered cortactin/p190RhoGAP interaction and weakened CCM2/Smurf1 binding to be involved in GTP-RhoA reduction and total RhoA increase, respectively. Moreover, we find that cytokinesis defects induced by Arp2/3 inhibition can be rescued by activating RhoA. Our study reveals an intricate feedback from the actin cytoskeleton to the small GTPase. Our work highlights the role of Arp2/3-branched actin in signal transduction aside from its function in serving as critical cytoskeletal components to maintain cell morphology and motility.

WATER POTENTIAL MEASUREMENT, WATER COMPARTMENTATION AND WATER FLOW IN DACTYLIS GLOMERATI L. LEAVES

1983 ◽  
Vol 93 (1) ◽  
pp. 43-52 ◽  
Author(s):  
J. ROY ◽  
A. BERGER
Keyword(s):  
Water Potential ◽  
Water Flow ◽  
Potential Measurement

scholarly journals Actin-depolymerizing Factor and Cofilin-1 Play Overlapping Roles in Promoting Rapid F-Actin Depolymerization in Mammalian Nonmuscle Cells

2005 ◽  
Vol 16 (2) ◽  
pp. 649-664 ◽  
Author(s):  
Pirta Hotulainen ◽  
Eija Paunola ◽  
Maria K. Vartiainen ◽  
Pekka Lappalainen
Keyword(s):  
Cell Motility ◽  
Actin Filament ◽  
Actin Filaments ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Actin Depolymerizing Factor ◽  
Cytoskeletal Dynamics ◽  
Nonmuscle Cells ◽  
In Cells

Actin-depolymerizing factor (ADF)/cofilins are small actin-binding proteins found in all eukaryotes. In vitro, ADF/cofilins promote actin dynamics by depolymerizing and severing actin filaments. However, whether ADF/cofilins contribute to actin dynamics in cells by disassembling “old” actin filaments or by promoting actin filament assembly through their severing activity is a matter of controversy. Analysis of mammalian ADF/cofilins is further complicated by the presence of multiple isoforms, which may contribute to actin dynamics by different mechanisms. We show that two isoforms, ADF and cofilin-1, are expressed in mouse NIH 3T3, B16F1, and Neuro 2A cells. Depleting cofilin-1 and/or ADF by siRNA leads to an accumulation of F-actin and to an increase in cell size. Cofilin-1 and ADF seem to play overlapping roles in cells, because the knockdown phenotype of either protein could be rescued by overexpression of the other one. Cofilin-1 and ADF knockdown cells also had defects in cell motility and cytokinesis, and these defects were most pronounced when both ADF and cofilin-1 were depleted. Fluorescence recovery after photobleaching analysis and studies with an actin monomer-sequestering drug, latrunculin-A, demonstrated that these phenotypes arose from diminished actin filament depolymerization rates. These data suggest that mammalian ADF and cofilin-1 promote cytoskeletal dynamics by depolymerizing actin filaments and that this activity is critical for several processes such as cytokinesis and cell motility.

Influence of hydraulic conductance of xylem on water status in cuttings

1986 ◽  
Vol 16 (1) ◽  
pp. 98-102 ◽  
Author(s):  
Takefumi Ikeda ◽  
Tamio Suzaki
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Water Absorption ◽  
Water Potential ◽  
Water Flow ◽  
Water Status ◽  
Total Resistance ◽  
Low Level ◽  
Bordered Pits ◽  
Scanning Electron

The reduction in water potential of cuttings after planting in water closely was related to an increase in resistance to water flow in the xylem. From observations of water-conducting tissues using a scanning electron microscope, the increase in resistance to water flow of cuttings was caused by blockage of vessel lumens with tyloses for Populuscarolinensis and aspiration of bordered pits for Cryptomeriajaponica. Water status of cuttings decreased with time after planting and was maintained at a low level by water absorption through bark. After rooting, the total resistance to water flow decreased and the water status of cuttings increased.

STEADY STATE RESISTANCE TO WATER FLOW IN CORN UNDER WELL WATERED CONDITIONS

1975 ◽  
Vol 55 (4) ◽  
pp. 941-948 ◽  
Author(s):  
P. A. DUBÉ ◽  
K. R. STEVENSON ◽  
G. W. THURTELL ◽  
H. H. NEUMANN
Keyword(s):  
Water Potential ◽  
Water Flow ◽  
Leaf Water Potential ◽  
Water Movement ◽  
Leaf Water ◽  
In Vivo Detection ◽  
Staining Techniques ◽  
Total Plant ◽  
Potential Gradients

Determinations of plant resistance to water flow from measurements of leaf water potential at steady transpiration rates were made on different lines of corn (Zea mays L.). Two inbreds, Q188, a wilting mutant, and DR1, an inbred line shown to have at least some heat and drought tolerance under field conditions, were compared to a commercial single-cross hybrid, United 106. The purpose of the experiment was to isolate the cause of the wilting characteristic of Q188. A linear relationship was found between leaf water potential and transpiration rate for all lines. No water potential gradients were found at zero transpiration. Low total plant resistances were observed in United 106 and DR1, with the major resistance being in the root system in both genotypes. Although the resistance to water movement through the roots and lower stalk in Q188 did not appear to differ from those of the other lines, a much larger resistance was found in the upper stalk of Q188; resistance to water movement through the lower stalk (up to node 5) decreased as the plants matured from 55 to 70 days of age but no comparable changes occurred in the upper portions of the stem. In vivo detection of the xylem vessels with staining techniques confirmed the observed differences in resistances.

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