Vector analysis of steerable mechanical tension across nuclear lamina

2018 ◽  
Author(s):  
TingTing Chen ◽  
HuiWen Wu ◽  
YuXuan Wang ◽  
JinJun Shan ◽  
JiaRui Zhang ◽  
...  
Keyword(s):  
Osmotic Pressure ◽  
Intermediate Filaments ◽  
Nuclear Lamina ◽  
Optical Probe ◽  
Living Cells ◽  
Vector Analysis ◽  
Eukaryotic Cells ◽  
Mechanical Tension ◽  
Protein Nanoparticles ◽  
Cytoskeletal Tension

SUMMARYThe nucleus is the most prominent organelle in eukaryotic cells, and its deformation depends on interactions between the nuclear lamina (NL) and cytoskeleton structural tensions. The structural tensions can be quantified at a pico-Newton (pN) level using a genetically encoded optical probe. In living cells, NL tensions countered the 4.26pN resting strain imposed competitively by cytoskeletal tension. The depolymerization of microfilaments or microtubules drove an aberrant increase in outward osmotic pressure through the production of mass protein-nanoparticles. The osmotic pressure also served as a directional converter of inward cytoskeletal force, and contributed to the outward expansion of NL via the passive pull of intermediate filaments (IFs). The NL, but not IFs, can remotely detect extracellular osmosis pressure alterations, which are closely associated with highly polarized microfilament and microtubule structures and their directional force activities. The oxidative-induced increase of NL tension results from intracellular hyper-osmosis, associated closely with protein-nanoparticles production elicited by cofilin and stathmin activation. These data reveal that intracellular steerable forces interact direction-dependently to control NL tension in terms of their magnitude and vectors.

scholarly journals Effects of mechanical tension on protrusive activity and microfilament and intermediate filament organization in an epidermal epithelium moving in culture.

1986 ◽  
Vol 102 (4) ◽  
pp. 1400-1411 ◽  
Author(s):  
J Kolega
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Intermediate Filaments ◽  
Intermediate Filament ◽  
Mechanical Tension ◽  
Cytoskeletal Organization ◽  
Structural Support ◽  
Transmission Electron ◽  
Locomotive Activity ◽  
Filament Surface

Mechanical tension influences tissue morphogenesis and the synthetic, mitotic, and motile behavior of cells. To determine the effects of tension on epithelial motility and cytoskeletal organization, small, motile clusters of epidermal cells were artificially extended with a micromanipulated needle. Protrusive activity perpendicular to the axis of tension was dramatically suppressed. To determine the ultrastructural basis for this phenomenon, cells whose exact locomotive behavior was recorded cinemicrographically were examined by transmission electron microscopy. In untensed, forward-moving lamellar protrusions, microfilaments appear disorganized and anisotropically oriented. But in cytoplasm held under tension by micromanipulation or by the locomotive activity of other cells within the epithelium, microfilaments are aligned parallel to the tension. In non-spreading regions of the epithelial margin, microfilaments lie in tight bundles parallel to apparent lines of tension. Thus, it appears that tension causes alignment of microfilaments. In contrast, intermediate filaments are excluded from motile protrusions, being confined to the thicker, more central part of the cell. They roughly follow the contours of the cell, but are not aligned relative to tension even when microfilaments in the same cell are. This suggests that the organization of intermediate filaments is relatively resistant to physical distortion and the intermediate filaments may act as passive structural support within the cell. The alignment of microfilaments under tension suggests a mechanism by which tension suppresses protrusive activity: microfilaments aligned by forces exerted through filament-surface or filament-filament interconnections cannot reorient against such force and so cannot easily extend protrusions in directions not parallel to tension.

Visualization of intermediate filaments in living cells using fluorescently labeled desmin

1989 ◽  
Vol 12 (3) ◽  
pp. 127-138 ◽  
Author(s):  
B. Mittal ◽  
J. M. Sanger ◽  
J. W. Sanger
Keyword(s):  
Intermediate Filaments ◽  
Living Cells

scholarly journals THE KINETICS OF EXOSMOSIS OF WATER FROM LIVING CELLS

1927 ◽  
Vol 10 (5) ◽  
pp. 659-664 ◽  
Author(s):  
Morton McCutcheon ◽  
Baldwin Lucke
Keyword(s):  
Osmotic Pressure ◽  
Salt Concentration ◽  
Driving Force ◽  
Temperature Characteristic ◽  
Living Cells ◽  
Velocity Constant ◽  
Osmotic Equilibrium ◽  
Kinetics Of

1. The rate of exosmosis of water was studied in unfertilized Arbacia eggs, in order to bring out possible differences between the kinetics of exosmosis and endosmosis. 2. Exosmosis, like endosmosis, is found to follow the equation See PDF for Equation, in which a is the total volume of water that will leave the cell before osmotic equilibrium is attained, x is the volume that has already left the cell at time t, and k is the velocity constant. 3. The velocity constants of the two processes are equal, provided the salt concentration of the medium is the same. 4. The temperature characteristic of exosmosis, as of endomosis, is high. 5. It is concluded that the kinetics of exosmosis and endosmosis of water in these cells are identical, the only difference in the processes being in the direction of the driving force of osmotic pressure.

scholarly journals A Balance Between Intermediate Filaments and Microtubules Maintains Nuclear Architecture in the Cardiomyocyte

2020 ◽  
Vol 126 (3) ◽  
Author(s):  
Julie Heffler ◽  
Parisha P. Shah ◽  
Patrick Robison ◽  
Sai Phyo ◽  
Kimberly Veliz ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Intermediate Filaments ◽  
Genome Organization ◽  
Contractile Function ◽  
Nuclear Architecture ◽  
Super Resolution ◽  
Nuclear Lamina ◽  
Linc Complex ◽  
Spectrin Repeat ◽  
Balance Of Forces

Rationale: Mechanical forces are transduced to nuclear responses via the linkers of the nucleoskeleton and cytoskeleton (LINC) complex, which couples the cytoskeleton to the nuclear lamina and associated chromatin. While disruption of the LINC complex can cause cardiomyopathy, the relevant interactions that bridge the nucleoskeleton to cytoskeleton are poorly understood in the cardiomyocyte, where cytoskeletal organization is unique. Furthermore, while microtubules and desmin intermediate filaments associate closely with cardiomyocyte nuclei, the importance of these interactions is unknown. Objective: Here, we sought to determine how cytoskeletal interactions with the LINC complex regulate nuclear homeostasis in the cardiomyocyte. Methods and Results: To this end, we acutely disrupted the LINC complex, microtubules, actin, and intermediate filaments and assessed the consequences on nuclear morphology and genome organization in rat ventricular cardiomyocytes via a combination of super-resolution imaging, biophysical, and genomic approaches. We find that a balance of dynamic microtubules and desmin intermediate filaments is required to maintain nuclear shape and the fidelity of the nuclear envelope and lamina. Upon depletion of desmin (or nesprin [nuclear envelope spectrin repeat protein]-3, its binding partner in the LINC complex), polymerizing microtubules collapse the nucleus and drive infolding of the nuclear membrane. This results in DNA damage, a loss of genome organization, and broad transcriptional changes. The collapse in nuclear integrity is concomitant with compromised contractile function and may contribute to the pathophysiological changes observed in desmin-related myopathies. Conclusions: Disrupting the tethering of desmin to the nucleus results in a loss of nuclear homeostasis and rapid alterations to cardiomyocyte function. Our data suggest that a balance of forces imposed by intermediate filaments and microtubules is required to maintain nuclear structure and genome organization in the cardiomyocyte.

Connections of intermediate filaments with the nuclear lamina and the cell periphery

1987 ◽  
Vol 59 (3) ◽  
pp. 193-203 ◽  
Author(s):  
Y. Katsuma ◽  
S. H. Swierenga ◽  
N. Marceau ◽  
S. W. French
Keyword(s):  
Intermediate Filaments ◽  
Nuclear Lamina ◽  
Cell Periphery

scholarly journals Apparent stiffness of vimentin intermediate filaments in living cells and its relation with other cytoskeletal polymers

2020 ◽  
Vol 1867 (8) ◽  
pp. 118726 ◽  
Author(s):  
Mariano Smoler ◽  
Giovanna Coceano ◽  
Ilaria Testa ◽  
Luciana Bruno ◽  
Valeria Levi
Keyword(s):  
Intermediate Filaments ◽  
Living Cells ◽  
Apparent Stiffness

scholarly journals Notes

1933 ◽  
Vol 112 (779) ◽  
pp. 477-479
Keyword(s):  
Osmotic Pressure ◽  
Recent Work ◽  
Living Cell ◽  
Biological Theory ◽  
Freezing Point ◽  
Living Cells ◽  
Hen’S Egg ◽  
Chemical Complex ◽  
The Difference ◽  
The Many

Recent work on the osmotic pressure of the hen’s egg has introduced a sense of uncertainty as to the value of the many comparisons which have been made between osmotic pressures of the blood, body fluids, and surrounding media. The uncertainty pertains not to theory but to a simple matter of fact and, as this involves that most fundamental datum for biological theory—viz., the state of the water in the living cell—there is urgent need to have it cleared up. The fact in dispute is the freezing point of the yolk and white of the bird’s egg. Atkins in 1909 by measurements, obviously made with the greatest care, found “no difference between the freezing point of white and yolk of the same egg and a mixture of white and yolk gave the same depression.” Atkins (1909) used the ordinary Beckmann technique and so, too, did Straub (1929) twenty years later, but with a surprisingly different result for he found a constant difference between white and yolk of the hen’s egg amounting on the average to —0·15° C. A. V. Hill (1930) confirmed Straub’s (1929) finding by a different method. He compared the fall in temperature caused by evaporation with that of water and from the difference calculated the osmotic pressure. Howard (1932) using the Beckmann method again found no difference in the freezing point of white and yolk. In these measurements the yolk was puddled by stirring so that at sometime or another the structure was broken down. Yolk is not only a chemical complex but it is alive, gross mechanical disturbance might, therefore, have the effect it usually has on living cells and cause chemical breakdown with consequent fall of the freezing point. Hale’s experiments were designed to explore this possibility by observing directly the freezing point of intact yolk and white.

scholarly journals Differential basal-to-apical accessibility of lamin A/C epitopes in the nuclear lamina regulated by changes in cytoskeletal tension

2015 ◽  
Vol 14 (12) ◽  
pp. 1252-1261 ◽  
Author(s):  
Teemu O. Ihalainen ◽  
Lina Aires ◽  
Florian A. Herzog ◽  
Ruth Schwartlander ◽  
Jens Moeller ◽  
...  
Keyword(s):  
Nuclear Lamina ◽  
Lamin A ◽  
Cytoskeletal Tension
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