Computational analysis of the tether-pulling experiment to probe plasma membrane-cytoskeleton interaction in cells

Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205, USA.
Physical Review E (Impact Factor: 2.29). 10/2009; 80(4 Pt 1):041905. DOI: 10.1103/PhysRevE.80.041905
Source: PubMed


Tethers are thin membrane tubes that can be formed when relatively small and localized forces are applied to cellular membranes and lipid bilayers. Tether pulling experiments have been used to better understand the fine membrane properties. These include the interaction between the plasma membrane and the underlying cytoskeleton, which is an important factor affecting membrane mechanics. We use a computational method aimed at the interpretation and design of tether pulling experiments in cells with a strong membrane-cytoskeleton attachment. In our model, we take into account the detailed information in the topology of bonds connecting the plasma membrane and the cytoskeleton. We compute the force-dependent piecewise membrane deflection and bending as well as modes of stored energy in three major regions of the system: body of the tether, membrane-cytoskeleton attachment zone, and the transition zone between the two. We apply our method to three cells: cochlear outer hair cells (OHCs), human embryonic kidney (HEK) cells, and Chinese hamster ovary (CHO) cells. OHCs have a special system of pillars connecting the membrane and the cytoskeleton, and HEK and CHO cells have the membrane-cytoskeleton adhesion arrangement via bonds (e.g., PIP2), which is common to many other cells. We also present a validation of our model by using experimental data on CHO and HEK cells. The proposed method can be an effective tool in the analyses of experiments to probe the properties of cellular membranes.

Download full-text


Available from: Bahman Anvari,
34 Reads
  • Source
    • "Both the physics of cell membrane deformation and the mechanics of ligandreceptor bonds have been studied extensively. Micropipette, atomic force microscope (AFM), optical trap, and magnetic bead techniques have been used to pull membrane tethers from cells and probe the properties of the cell membrane [5]. The diameter of the extracted tether depends on the membrane surface tension and bending rigidity and, if the tether is being extended at a constant velocity, the membrane viscosity [6] [7]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: When a ligand that is bound to an integral membrane receptor is pulled, the membrane and the underlying cytoskeleton can deform before either the membrane delaminates from the cytoskeleton or the ligand detaches from the receptor. If the membrane delaminates from the cytoskeleton, it may be further extruded and form a membrane tether. We develop a phenomenological model for this process by assuming that deformations obey Hooke's law up to a critical force at which the cell membrane locally detaches from the cytoskeleton and a membrane tether forms. We compute the probability of tether formation and show that tethers can be extruded only within an intermediate range of force loading rates and pulling velocities. The mean tether length that arises at the moment of ligand detachment is computed as are the force loading rates and pulling velocities that yield the longest tethers.
    Physical Biology 06/2010; 7(2):026002. DOI:10.1088/1478-3975/7/2/026002 · 2.54 Impact Factor
  • Source
  • Clinical Endocrinology News 10/2007; 2(10):22-22. DOI:10.1016/S1558-0164(07)70557-6
Show more