Non-affinity of the erythrocyte membrane - The role of band 3 rearrangement under thermal fluctuations

International Conference on Polymer Science & Engineering

August 22-24, 2016 New Orleans, USA

Ivana Pajic Lijakovic

Belgrade University, Serbia

Posters & Accepted Abstracts: J Material Sci Eng

Abstract :

The erythrocyte membrane structural changes under thermal fluctuations are considered in the context of energy transfer and dissipation caused by the cortex-bilayer coupling. The fluctuations induce alternating expansion and compression of the membrane parts in order to ensure surface and volume conservation. These changes could induce phosphorylation of some actin junctions due to ensuring the membrane integrity and function which cause additional energy dissipation. The liberated parts of the spectrin filaments freely fluctuate. Their fluctuations induce excitation of the surrounding band 3-spectrin low affinity complexes and influence their association-dissociation dynamics. Dissociated band 3 molecules could freely diffuse through the membrane. The freely diffusing band 3 molecules could form clusters which induces additional structural inhomogeneities. High affinity band 3-ankyrin complexes located near the center of spectrin tetramers survive these energetic perturbations. Consequently, the spectrin filament conformations are dependent on the state of: (1) band 3 complexes with adducin located at the spectrin-actin junction complexes and (2) band 3 complexes with spectrin located along the spectrin filaments. Complex dynamics of the single filament conformations is connected with cumulative effects of changes the state of the protein complexes. These structural changes caused anomalous nature of energy dissipation with damping effects. The spectrin mobility reduction is the key factor which influences the spectrin inter-filament interactions and the cortex nonlinear stiffening in affine regime (for smaller relaxation times). Nonlinear nature of the cortex stiffening in non-affine regime (for higher relaxation times) is connected with the spectrin intra-filament interactions.

Biography :

Email: iva@tmf.bg.ac.rs