Seminar by Dr. Antoine Triller

Institut de Biologie de l'École Normale Supérieure, Paris (France)

The dynamic synapse at mesoscale: reconciling stability and plasticity

The efficiency and accuracy of neurotransmission depends on two apparently antagonist properties of synaptic membrane: the stability of its organization and its ability to adapt to plasticity events. In addition, the structural stability of synapses has to be reconciled with the notion that cell membranes are fluid. Membrane molecules are compelled to move within the membrane surface due to thermal Brownian agitation, which favors the homogeneous distribution of molecules. As a result, neurons spend energy to stop or reduce these movements, and maintain molecules in certain locations. We demonstrated rapid exchanges between synaptic and extra-synaptic receptors and we showed that transient stabilization of receptors at synapses occurs by interaction with partners, such as scaffold proteins.

 

Combining single particle tracking and super-resolution methods, open access to molecular counting and energy involved in receptor-scaffold interactions as well as on and off rate of molecular interactions. Thus, beyond super-resolution methods is chemistry “in cellulo” accounting for the regulation of receptor number and consecutively that of synaptic strength. We will present some modelling approaches related to this issue.

 

Ultimately, the dynamic regulations of receptor-scaffold and scaffold–scaffold interactions appear as a central tenet for the maintenance and plasticity-related changes of receptor numbers at synapses.