Annals of Biomedical Engineering

, Volume 33, Issue 10, pp 1387–1404 | Cite as

3-D Nanomechanics of an Erythrocyte Junctional Complex in Equibiaxial and Anisotropic Deformations

  • Carlos Vera
  • Robert Skelton
  • Frederic Bossens
  • Lanping Amy Sung


The erythrocyte membrane skeleton deforms constantly in circulation, but the mechanics of a junctional complex (JC) in the network is poorly understood. We previously proposed a 3-D mechanical model for a JC (Sung, L. A., and C. Vera. Protofilament and hexagon: A three-dimensional mechanical model for the junctional complex in the erythrocyte membrane skeleton. Ann Biomed Eng 31:1314–1326, 2003) and now developed a mathematical model to compute its equilibrium by dynamic relaxation. We simulated deformations of a single unit in the network to predict the tension of 6 αβ spectrin (Sp) (top, middle, and bottom pairs), and the attitude of the actin protofilament [pitch (θ), yaw (φ) and roll (ψ) angles]. In equibiaxial deformation, 6 Sp would not begin their first round of “single domain unfolding in cluster” until the extension ratio (λ) reach ~3.6, beyond the maximal sustainable λ of ~2.67. Before Sp unfolds, the protofilament would gradually raise its pointed end away from the membrane, while φ and ψ remain almost unchanged. In anisotropic deformation, protofilaments would remain tangent but swing and roll drastically at least once between λ i = 1.0 and ~2.8, in a deformation angle- and λ i -dependent fashion. This newly predicted nanomechanics in response to deformations may reveal functional roles previous unseen for a JC, and molecules associated with it, during erythrocyte circulation.


Actin Nanomechanics Deformation Protofilament Spectrin 


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Copyright information

© Biomedical Engineering Society 2005

Authors and Affiliations

  • Carlos Vera
    • 1
  • Robert Skelton
    • 2
  • Frederic Bossens
    • 2
  • Lanping Amy Sung
    • 1
    • 3
  1. 1.Department of BioengineeringJacobs School of Engineering, University of CaliforniaSan Diego, La Jolla
  2. 2.Department of Mechanical and Aerospace EngineeringJacobs School of Engineering, University of CaliforniaSan Diego, La Jolla
  3. 3.Department of Bioengineering, and Center for Molecular GeneticsUniversity of CaliforniaLa Jolla

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