Fast and reversible trapping of surface glycine receptors by gephyrin.
Variations in receptor number at a given synapse are known to contribute to synaptic plasticity, but methods used to establish this idea usually do not allow for the determination of the dynamics of these phenomena. We used single-particle tracking to follow in real time, on the cell surface, movements of the glycine receptor (GlyR) with or without the GlyR stabilizing protein gephyrin. GlyR alternated within seconds between diffusive and confined states. In the absence of gephyrin, GlyR were mostly freely diffusing. Gephyrin induced long confinement periods spatially associated with submembranous clusters of gephyrin. However, even when most receptors were stabilized, they still frequently made transitions through the diffusive state. These data show that receptor number in a cluster results from a dynamic equilibrium between the pools of stabilized and freely mobile receptors. Modification of this equilibrium could be involved in regulation of the number of receptors at synapses.
Biologie Cellulaire de la Synapse N&P INSERM U497, Ecole Normale Supérieure 46, rue d'Ulm 75005, Paris, France.
J
J
Meier
C
C
Vannier
A
A
Sergé
A
A
Triller
D
D
Choquet
D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D002352:Carrier Proteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008863:Microspheres; D051381:Rats; D017207:Rats, Sprague-Dawley; D018009:Receptors, Glycine / Q000378:metabolism*; D013570:Synaptic Membranes / Q000378:metabolism*; D013997:Time Factors
D002352:Carrier Proteins; D008565:Membrane Proteins; D018009:Receptors, Glycine; C073441:gephyrin