Open Access

ARTICLE

Bryan Pfister¹, George Oyler², Michael Betenbaugh³, Gang Bao⁴
Molecular & Cellular Biomechanics, Vol.1, No.4, pp. 233-244, 2004, DOI:10.3970/mcb.2004.001.233
Abstract The Bcl-2 family of proteins has recently been implicated as a possible player in the complex cascade of neural cell death due to traumatic brain injuries. However, it is unclear if the Bcl-2 pathways are activated in mechanically injured neurons. Here we report the effects of BclX_L and Bax over-expression on stretch-induced neural cell death using an in vitro uniaxial stretch model of traumatic axonal injury. Specifically, YFP, YFP-tagged Bax and YFP-tagged BclX_L proteins were expressed in differentiated NG108-15 cells and stretch-injury assays were carried out at different strain and strain rate combinations. As a control, insults More >

View

1351

Download

1105

Open Access

ARTICLE

Warren D. Marcus^1,2, Rodger P. McEver³, Cheng Zhu¹
Molecular & Cellular Biomechanics, Vol.1, No.4, pp. 245-252, 2004, DOI:10.3970/mcb.2004.001.245
Abstract When a cell adhered to another cell or substratum via surface proteins is forced to detach, lipid membrane tethers are often extruded from the cell surface before the protein bond dissociates. For example, during the inflammatory reaction leukocytes roll on the surface of activated endothelial cells. The rolling adhesion is mediated by interactions of selectins with their ligands, e.g., P-selectin glycoprotein ligand (PSGL)-1, which extrudes membrane tethers from the surfaces of both leukocytes and endothelial cells. Membrane tether extrusion has been suggested to regulate leukocyte rolling. Here we examine several factors that may affect forces… More >

View

1525

Download

1095

Open Access

ARTICLE

M.R. Kaazempur Mofrad^1,2, J. Golji², N.A. Abdul Rahim², R.D. Kamm³
Molecular & Cellular Biomechanics, Vol.1, No.4, pp. 253-266, 2004, DOI:10.3970/mcb.2004.001.253
Abstract Membrane-bound integrin receptors are linked to intracellular signaling pathways through focal adhesion kinase (FAK). FAK tends to colocalize with integrin receptors at focal adhesions through its C-terminal focal adhesion targeting (FAT) domain. Through recruitment and binding of intracellular proteins, FAs transduce signals between the intracellular and extracellular regions that regulate a variety of cellular processes including cell migration, proliferation, apoptosis and detachment from the ECM. The mechanism of signaling through the cell is of interest, especially the transmission of mechanical forces and subsequent transduction into biological signals. One hypothesis relates mechanotransduction to conformational changes in More >

View

1460

Download

1027

Open Access

ARTICLE

Hong Qian¹
Molecular & Cellular Biomechanics, Vol.1, No.4, pp. 267-278, 2004, DOI:10.3970/mcb.2004.001.267
Abstract In recent single-particle tracking (SPT) measurements on Listeria monocytogenes motility in cells [Kuo and McGrath (2000)], the actin-based stochastic dynamics of the bacterium movement has been analyzed statistically in terms of the mean-square displacement (MSD) of the trajectory. We present a stochastic analysis of a simplified polymerization Brownian ratchet (BR) model in which motions are limited by the bacterium movement. Analytical results are obtained and statistical data analyses are investigated. It is shown that the MSD of the stochastic bacterium movement is a monotonic quadratic function while the MSD for detrended trajectories is linear. Both the More >

View

1511

Download

1193

Open Access

ARTICLE

A. Shukla^1,1, A.R. Dunn^2,2, M.A. Moses^3,3, K.J. Van Vliet^4,4
Molecular & Cellular Biomechanics, Vol.1, No.4, pp. 279-290, 2004, DOI:10.3970/mcb.2004.001.279
Abstract Although it is established that endothelial cells can respond to external mechanical cues (e.g., alignment in the direction of fluid shear stress), the extent to which mechanical stress and strain applied via the endothelial cell substrate impact biomolecular and cellular processes is not well-understood. This issue is particularly important in the context of inflammation, vascular remodeling, and cancer progression, as each of these processes occurs concurrently with localized increases in strain and marked changes in molecules secreted by adjacent cells. Here, we systematically vary the level and duration of cyclic tensile strain applied to human… More >

View

1776

Download

1048

Open Access

ARTICLE

Muhammad H. Zaman¹, Mohammad R. Kaazempur-Mofrad²
Molecular & Cellular Biomechanics, Vol.1, No.4, pp. 291-302, 2004, DOI:10.3970/mcb.2004.001.291
Abstract α-actinin, an actin binding protein, plays a key role in cell migration, cross-links actin filaments in the Z-disk, and is a major component of contractile muscle apparatus. The flexibility of the molecule is critical to its function. The flexibility of various regions of the molecule, including the linker connecting central subunits is studied using constant force steered molecular dynamics simulations. The linker, whose structure has been a subject of debate, is predicted to be semi-flexible. The flexibility of the linker is compared to all possible segments of equal length throughout the molecule. The stretching profile More >

View

1473

Download

1001