title: Superdiffusive motion of membrane-targeting C2 domains.
abstract: Membrane-targeting domains play crucial roles in the recruitment of signalling molecules to the plasma membrane. For most peripheral proteins, the protein-to-membrane interaction is transient. After proteins dissociate from the membrane they have been observed to rebind following brief excursions in the bulk solution. Such membrane hops can have broad implications for the efficiency of reactions on membranes. We study the diffusion of membrane-targeting C2 domains using single-molecule tracking in supported lipid bilayers. The ensemble-averaged mean square displacement (MSD) exhibits superdiffusive behaviour. However, traditional time-averaged MSD analysis of individual trajectories remains linear and does not reveal superdiffusion. Our observations are explained in terms of bulk excursions that introduce jumps with a heavy-tail distribution. These hopping events allow proteins to explore large areas in a short time. The experimental results are shown to be consistent with analytical models of bulk-mediated diffusion and numerical simulations.
authors.affiliation: Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Grace
authors.initials: G
authors.lastname: Campagnola
authors.affiliation: School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Kanti
authors.initials: K
authors.lastname: Nepal
authors.affiliation: School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Bryce W
authors.initials: BW
authors.lastname: Schroder
authors.affiliation: Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA.|School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Olve B
authors.initials: OB
authors.lastname: Peersen
authors.affiliation: School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA.|Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Diego
authors.initials: D
authors.lastname: Krapf
mesh_terms: D002462:Cell Membrane / Q000378:metabolism*; D004058:Diffusion; D005982:Glutathione Transferase / Q000737:chemistry; D008051:Lipid Bilayers / Q000378:metabolism; D009038:Motion; D009716:Numerical Analysis, Computer-Assisted; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry*; D050857:Synaptotagmins / Q000737:chemistry
chemical_list: D008051:Lipid Bilayers; D011506:Proteins; D050857:Synaptotagmins; D005982:Glutathione Transferase