title: Changes in single-molecule integrin dynamics linked to local cellular behavior.
abstract: Recent advances in light microscopy permit visualization of the behavior of individual molecules within dense macromolecular ensembles in live cells. It is now conceptually possible to relate the dynamic organization of molecular machinery to cellular function. However, inherent heterogeneities, as well as disparities between spatial and temporal scales, pose substantial challenges in deriving such a relationship. New approaches are required to link discrete single-molecule behavior with continuous cellular-level processes. Here we combined intercalated molecular and cellular imaging with a computational framework to detect reproducible transient changes in the behavior of individual molecules that are linked to cellular behaviors. Applying our approach to integrin transmembrane receptors revealed a spatial density gradient underlying characteristic molecular density increases and mobility decreases, indicating the subsequent onset of local protrusive activity. Integrin mutants further revealed that these density and mobility transients are separable and depend on different binding domains within the integrin cytoplasmic tail. Our approach provides a generalizable paradigm for dissecting dynamic spatiotemporal molecular behaviors linked to local cellular events.
authors.affiliation: Department of Biophysics, UT Southwestern Medical Center, Dallas, TX 75390-8816 galbrcat@ohsu.edu khuloud.jaqaman@utsouthwestern.edu galbrjam@ohsu.edu.
authors.forename: Khuloud
authors.initials: K
authors.lastname: Jaqaman
authors.affiliation: OHSU Center for Spatial Systems Biomedicine and Department of Biomedical Engineering, Portland, OR 97201-5042 galbrcat@ohsu.edu khuloud.jaqaman@utsouthwestern.edu galbrjam@ohsu.edu.
authors.forename: James A
authors.initials: JA
authors.lastname: Galbraith
authors.affiliation: National High Magnet Field Laboratory, Florida State University, Tallahassee, FL 32310.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Davidson
authors.affiliation: OHSU Center for Spatial Systems Biomedicine and Department of Biomedical Engineering, Portland, OR 97201-5042 galbrcat@ohsu.edu khuloud.jaqaman@utsouthwestern.edu galbrjam@ohsu.edu.
authors.forename: Catherine G
authors.initials: CG
authors.lastname: Galbraith
mesh_terms: D000818:Animals; D016466:CHO Cells; D003412:Cricetulus; D004058:Diffusion; D006801:Humans; D016023:Integrins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D046911:Macromolecular Substances; D008856:Microscopy, Fluorescence / Q000379:methods; D008954:Models, Biological; D056004:Molecular Dynamics Simulation; D057054:Molecular Imaging / Q000379:methods*; D013329:Structure-Activity Relationship
chemical_list: D016023:Integrins; D046911:Macromolecular Substances