title: Neurotransmitter receptor dynamics studied in vivo by reversible photo-unbinding of fluorescent ligands.
abstract: We show that fluorescently tagged ligands with high affinity for their targets can be reversibly unbound by focused laser excitation. By sequential unbinding and relabeling with different colors of alpha-bungarotoxin, we selectively labeled adjacent pools of acetylcholine receptors (AChRs) at neuromuscular junctions of adult mice. Timelapse imaging in vivo revealed that synaptic AChRs completely intermingle over approximately 4 days and many extrasynaptic AChRs are incorporated into the synapse each day. In mice that lacked alpha-dystrobrevin, a component of the dystrophin-glycoprotein complex, rates of AChR turnover, and intermingling were increased approximately 4- to 5-fold. These results demonstrate remarkable molecular dynamism underlying macroscopic stability of the postsynaptic membrane, and establish alpha-dystrobrevin as a key control point for regulation of mobility and turnover.
authors.affiliation: Department of Anatomy and Neurobiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Akaaboune
authors.forename: R Mark
authors.initials: RM
authors.lastname: Grady
authors.forename: Steve
authors.initials: S
authors.lastname: Turney
authors.forename: Joshua R
authors.initials: JR
authors.lastname: Sanes
authors.forename: Jeff W
authors.initials: JW
authors.lastname: Lichtman
mesh_terms: D000818:Animals; D001667:Binding, Competitive / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000172:deficiency / Q000235:genetics; D049029:Dystrophin-Associated Proteins; D005260:Female; D005456:Fluorescent Dyes / Q000378:metabolism*; D008024:Ligands; D008027:Light; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics; D051379:Mice; D008856:Microscopy, Fluorescence; D009469:Neuromuscular Junction / Q000378:metabolism; D011950:Receptors, Cholinergic / Q000378:metabolism / Q000502:physiology; D017981:Receptors, Neurotransmitter / Q000378:metabolism* / Q000502:physiology
chemical_list: D003598:Cytoskeletal Proteins; D049029:Dystrophin-Associated Proteins; D005456:Fluorescent Dyes; D008024:Ligands; D008565:Membrane Proteins; D011950:Receptors, Cholinergic; D017981:Receptors, Neurotransmitter; C098885:dystrobrevin