scholarly journals Flow arrest in the plasma membrane

2019 ◽  
Author(s):  
Michael Chein ◽  
Eran Perlson ◽  
Yael Roichman
Keyword(s):  
Mechanical Properties ◽  
Plasma Membrane ◽  
Cell Membrane ◽  
Domain Size ◽  
Decay Length ◽  
Neurotrophin Receptors ◽  
Long Range Correlations ◽  
Fluid Membranes ◽  
A Cell ◽  
Do So

AbstractThe arrangement of receptors in the plasma membrane strongly affects the ability of a cell to sense its environment both in terms of sensitivity and in terms of spatial resolution. The spatial and temporal arrangement of the receptors is affected in turn by the mechanical properties and the structure of the cell membrane. Here we focus on characterizing the flow of the membrane in response to the motion of a protein embedded in it. We do so by measuring the correlated diffusion of extracellularly tagged transmembrane neurotrophin receptors TrkB and p75 on transfected neuronal cells. In accord with previous reports, we find that the motion of single receptors exhibits transient confinement to sub-micron domains. We confirm predictions based on hydrodynamics of fluid membranes, finding long-range correlations in the motion of the receptors in the plasma membrane. However, we discover that these correlations do not persist for long ranges, as predicted, but decay exponentially, with a typical decay length on the scale of the average confining domain size.

Rotary movements and fluid membranes in termite flagellates

1976 ◽  
Vol 20 (3) ◽  
pp. 619-638
Author(s):  
S.L. Tamm ◽  
S. Tamm
Keyword(s):  
Plasma Membrane ◽  
Comparative Analysis ◽  
Cell Membrane ◽  
Shear Zone ◽  
Surrounding Medium ◽  
The Other ◽  
Visual Evidence ◽  
Fluid Membranes ◽  
Internal Motor ◽  
Rotary Motor

We previously described a remarkable type of cell motility that provided direct, visual evidence for the fluid nature of cell membranes. The movement involved continual, unidirectional rotation of one part of a protozoan, including the plasma membrane and cytoplasmic organelles, in relation to a neighbouring part. The cell membrane in the ‘shear zone’ appeared continuous with that of the rest of the cell. The rotary motor consisted, at least in part, of a non-contractile, microtubular axostyle which extended centrally through the cell. The protozoan was a devescovinid flagellate found in the hindgut of a Florida termite. In this paper, we have confirmed earlier reports of this type of motility in other kinds of devescovinids from Australian termites. By demonstrating continuity of the plasma membrane in the shear zone of the Australian devescovinids as well, we have obtained additional examples that provide direct, visual evidence for fluid membranes. A comparative analysis of rotational motility in various devescovinids revealed 2 different kinds of rotary mechanisms. Hyperdevescovina probably have an internal motor, in which one part of the cell exerts forces against another part, as in the Florida termite devescovinid. Devescovina species, on the other hand, have an external motor, in which flagellar and/or papillar movements exert forces against the surrounding medium. The structure of the axostyle in different devescovinids was compared, and its role in rotational motility discussed with respect to the behavioural data.

Extracellularly applied ruthenium red and cADP ribose elevate cytosolic Ca2+ in isolated rat osteoclasts

1996 ◽  
Vol 270 (3) ◽  
pp. F469-F475 ◽  
Author(s):  
O. A. Adebanjo ◽  
V. S. Shankar ◽  
M. Pazianas ◽  
B. J. Simon ◽  
F. A. Lai ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Potential ◽  
Cell Membrane ◽  
Cell Surface ◽  
Divalent Cation ◽  
Ruthenium Red ◽  
The Face ◽  
A Cell ◽  
Cation Sensing ◽  
Isolated Rat

We demonstrated recently that the divalent cation-sensing receptor on the osteoclast, the Ca2+ receptor (CaR), is a functional component of a cell surface-expressed ryanodine receptor-like molecule (RyR). The objective of the present study was to further characterize this putative RyR by use of the two well-known cell-impermeant RyR modulators, ruthenium red and adenosine 3',5'-cyclic diphosphate ribose (cADPr). We found that, when applied extracellularly, ruthenium red (5 x 10(-8)-10(-4) M) and cADPr (5 x 10(-6) M) triggered an elevation of cytosolic [Ca2+]. Depolarization of the cell membrane by the application of 0.1 M K+ in the presence of 5 x 10(-6) M. valinomycin resulted in a concentration-dependent increase in the magnitude of the cytosolic Ca2+ response to extracellular ruthenium red (5 x 10(-9) and 5 x 10(-5) M), a phenomenon that was not seen when osteoclasts were hyperpolarized using 5 x 10(-3) M K+ with 5 x 10(-6) M valinomycin. In the presence of an intact nonleaky cell membrane, these results would favor a plasma membrane locus of action for the two modulators. Furthermore, pretreatment of osteoclasts with either modulator resulted in a markedly attenuated cytosolic Ca2+ transient elicited in response to the CaR agonist Ni2+, thus confirming an interaction between the cADPr- and ruthenium red-sensitive sites and the osteoclast CaR. The inhibition of the cytosolic Ca2+ response to Ni2+ induced by ruthenium red remained unchanged in the face of membrane potential changes. Finally, the cytosolic Ca2+ response to caffeine (5 x 10(-4) M), another RyR modulator, was also strongly attenuated by pretreatment with 5 x 10(-9) M ruthenium red. We conclude that ruthenium red and cADPr act on plasma membrane-resident sites and that both these sites interact with the process of divalent cation sensing.

Extracting elastic properties and prestress of a cell using atomic force microscopy

2009 ◽  
Vol 24 (3) ◽  
pp. 1167-1171 ◽  
Author(s):  
C.Y. Zhang ◽  
Y.W. Zhang
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Elastic Modulus ◽  
Analytical Solution ◽  
Cell Membrane ◽  
Soft Phase ◽  
Force Microscopy ◽  
Apparent Modulus ◽  
Atomic Force ◽  
A Cell

An analytical solution was derived for the indentation of a cell using atomic force microscopy. It was found that the contribution of the cell membrane to the overall indentation stiffness is dependent on the size of the indenter. When a small indenter [for example, an atomic force microscopy (AFM) tip] is used to probe the mechanical properties of cells, the cell membrane and its prestress were important in interpreting indentation data. The solution allows the partition of contributions from the membrane and the interior soft phase. The apparent elastic modulus of the cell and the prestress of the cell membrane can be extracted. In addition, the modulus of the cell membrane could be estimated from the extracted apparent modulus if the interior soft phase of the cell was known and vice versa. However, when a large indenter is used (for example, a microbead attached to the cantilever beam of the AFM), the contribution of the cell membrane is negligible.

Laser-generated bubbles take aim at a cell membrane

Physics Today ◽  
2010 ◽  
Vol 63 (9) ◽  
pp. 17-17
Author(s):  
Mark Wilson
Keyword(s):  
Cell Membrane ◽  
A Cell

A Zebrafish Embryo Behaves both as a “Cortical Shell – Liquid Core” Structure and a Homogeneous Solid when Experiencing Mechanical Forces

2014 ◽  
Vol 20 (6) ◽  
pp. 1841-1847 ◽  
Author(s):  
Fei Liu ◽  
Dan Wu ◽  
Ken Chen
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Zebrafish Embryo ◽  
Large Strain ◽  
Liquid Core ◽  
Small Strain ◽  
Core Structure ◽  
Mechanical Forces ◽  
Cortical Shell ◽  
A Cell

AbstractMechanical properties are vital for living cells, and various models have been developed to study the mechanical behavior of cells. However, there is debate regarding whether a cell behaves more similarly to a “cortical shell – liquid core” structure (membrane-like) or a homogeneous solid (cytoskeleton-like) when experiencing stress by mechanical forces. Unlike most experimental methods, which concern the small-strain deformation of a cell, we focused on the mechanical behavior of a cell undergoing small to large strain by conducting microinjection experiments on zebrafish embryo cells. The power law with order of 1.5 between the injection force and the injection distance indicates that the cell behaves as a homogenous solid at small-strain deformation. The linear relation between the rupture force and the microinjector radius suggests that the embryo behaves as membrane-like when subjected to large-strain deformation. We also discuss the possible reasons causing the debate by analyzing the mechanical properties of F-actin filaments.

Line tension and the penetration of a cell membrane by an oil drop

1967 ◽  
Vol 17 (2) ◽  
pp. 246-251 ◽  
Author(s):  
N.L. Gershfeld ◽  
R.J. Good
Keyword(s):  
Cell Membrane ◽  
Line Tension ◽  
A Cell

scholarly journals Biological activity of liposome-encapsulated murine interferon gamma is mediated by a cell membrane receptor.

1985 ◽  
Vol 82 (11) ◽  
pp. 3688-3692 ◽  
Author(s):  
D. A. Eppstein ◽  
Y. V. Marsh ◽  
M. van der Pas ◽  
P. L. Felgner ◽  
A. B. Schreiber
Keyword(s):  
Biological Activity ◽  
Cell Membrane ◽  
Interferon Gamma ◽  
Membrane Receptor ◽  
A Cell
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