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retrograde-flow
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Analytical Solutions of Actin-Retrograde-Flow in a Circular Stationary Cell: A Mechanical Point of View
, Article Bulletin of Mathematical Biology ; Vol. 76, issue. 3 , March , 2014 , p. 744-760 ; 00928240 ; Firoozabadi, B ; Saidi, M. S ; Sharif University of Technology
Abstract
The network of actin filaments in the lamellipodium (LP) of stationary and migrating cells flows in a retrograde direction, from the membrane periphery toward the cell nucleus. We have theoretically studied this phenomenon in the circular stationary (fully spread) cells. Adopting a continuum view on the LP actin network, new closed-form solutions are provided for the actin-retrograde-flow (ARF) in a polar coordinate system. Due to discrepancy in the mechanical models of the actin network in the ARF regime, solutions are provided for both assumptions of solid and fluid behavior. Other involved phenomena, including polymerizing machine at the membrane periphery, cytosol drag, adhesion...
Continuum model of actin-myosin flow
, Article 2013 20th Iranian Conference on Biomedical Engineering, ICBME 2013 ; December , 2013 , Pages 98-102 ; Firoozabadi, B ; Saidi, M. S ; Sharif University of Technology
IEEE Computer Society
2013
Abstract
The front part of a cell is divided to two regions called lamellum and lamellipodium (lamellipodial). This part plays an essential role for cell migration. Indeed, there are many protein filaments called actin in lamellum and lamellipodium, which induce the cell motion with polymerization in the leading edge of the cell. The actin filaments adhere to the extracellular matrix (ECM) by means of focal adhesions and they have contact by myosin motor proteins. The myosin motor proteins cause actin retrograde and anterograde flow exerted contractile stress on them. The focal adhesions exert frictional stress on the actin filaments. In this work, we developed a two-dimensional continuum model of...
Theoretical modeling of actin-retrograde-flow passing clusters of confined T cell receptors
, Article Mathematical Biosciences ; Volume 283 , 2017 , Pages 1-6 ; 00255564 (ISSN) ; Firoozabadi, B ; Saidi, M. S ; Sharif University of Technology
Elsevier Inc
2017
Abstract
Through the activation process of T cells, actin filaments move from the cell periphery toward the cell center. The moving filaments engage with T cell receptors and thus contribute to transportation of the signaling molecules. To study the connection between the moving actin filaments and T cell receptors, an experiment available in the literature has measured filaments flow velocity passing over a region of confined clusters of receptors. It shows that flow velocity decreases in the proximity of the receptors, and then regains its normal value after traversing the region, suggesting a dissipative friction-like connection. In this work, we develop a minimal theoretical model to re-examine...