title: Interaction between single molecules of Mac-1 and ICAM-1 in living cells: an atomic force microscopy study.
abstract: The interaction between integrin macrophage differentiation antigen associated with complement three receptor function (Mac-1) and intercellular adhesion molecule-1 (ICAM-1), which is controlled tightly by the ligand-binding activity of Mac-1, is central to the regulation of neutrophil adhesion in host defense. Several "inside-out" signals and extracellular metal ions or antibodies have been found to activate Mac-1, resulting in an increased adhesiveness of Mac-1 to its ligands. However, the molecular basis for Mac-1 activation is not well understood yet. In this work, we have carried out a single-molecule study of Mac-1/ICAM-1 interaction force in living cells by atomic force microscopy (AFM). Our results showed that the binding probability and adhesion force of Mac-1 with ICAM-1 increased upon Mac-1 activation. Moreover, by comparing the dynamic force spectra of different Mac-1 mutants, we expected that Mac-1 activation is governed by the downward movement of its alpha7 helix.
authors.affiliation: Department of Neurobiology, Institute of Neuroscience, Second Military Medical University, Shanghai, China.
authors.forename: Huayan
authors.initials: H
authors.lastname: Yang
authors.forename: Junping
authors.initials: J
authors.lastname: Yu
authors.forename: Guo
authors.initials: G
authors.lastname: Fu
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Shi
authors.forename: Lin
authors.initials: L
authors.lastname: Xiao
authors.forename: Yizhang
authors.initials: Y
authors.lastname: Chen
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Fang
authors.forename: Cheng
authors.initials: C
authors.lastname: He
mesh_terms: D000818:Animals; D016466:CHO Cells; D002470:Cell Survival; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism* / Q000648:ultrastructure*; D016177:Macrophage-1 Antigen / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure*; D018625:Microscopy, Atomic Force; D011485:Protein Binding; D017433:Protein Structure, Secondary