title: Tension-compression asymmetry in the binding affinity of membrane-anchored receptors and ligands.
abstract: Cell adhesion plays a crucial role in many biological processes of cells, e.g., immune responses, tissue morphogenesis, and stem cell differentiation. An essential problem in the molecular mechanism of cell adhesion is to characterize the binding affinity of membrane-anchored receptors and ligands under different physiological conditions. In this paper, a theoretical model is presented to study the binding affinity between a large number of anchored receptors and ligands under both tensile and compressive stresses, and corroborated by demonstrating excellent agreement with Monte Carlo simulations. It is shown that the binding affinity becomes lower as the magnitude of the applied stress increases, and drops to zero at a critical tensile or compressive stress. Interestingly, the critical compressive stress is found to be substantially smaller than the critical tensile stress for relatively long and flexible receptor-ligand complexes. This counterintuitive finding is explained by using the Euler instability theory of slender columns under compression. The tension-compression asymmetry in the binding affinity of anchored receptors and ligands depends subtly on the competition between the breaking and instability of their complexes. This study helps in understanding the role of mechanical forces in cell adhesion mediated by specific binding molecules.
authors.affiliation: International Center for Applied Mechanics, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Guang-Kui
authors.initials: GK
authors.lastname: Xu
authors.affiliation: International Center for Applied Mechanics, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Zishun
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.
authors.forename: Xi-Qiao
authors.initials: XQ
authors.lastname: Feng
authors.affiliation: School of Engineering, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: Huajian
authors.initials: H
authors.lastname: Gao
mesh_terms: D002448:Cell Adhesion; D002462:Cell Membrane / Q000378:metabolism*; D019245:Compressive Strength; D008024:Ligands; D008565:Membrane Proteins / Q000378:metabolism*; D008954:Models, Biological; D009010:Monte Carlo Method; D013314:Stress, Mechanical
chemical_list: D008024:Ligands; D008565:Membrane Proteins