Séminaire du LPTMS: Jonas Ranft

Dynamics of synaptic domains: scaffold-protein aggregation at the postsynaptic membrane

Jonas Ranft, Laboratoire de Physique Statistique de l’ENS

The dynamic nature of synaptic receptor populations poses the question of how the number of receptors can be reliably controlled in spite of their continuous dynamic reorganization. Increasing evidence points to the stabilizing role of submembranous scaffold clusters that are formed by oligomerization of specific proteins. However, it is not clear in turn how these scaffold clusters form, what controls their sizes and what is their lifetime as compared to the protein turnover they are themselves subject to. Here, we investigate the dynamics of synaptic domains by studying a simplified model of the scaffold dynamics at the postsynaptic neuronal membrane. We find by using particle-based simulations, as well as analytic calculations, that for all parameter regimes, the system eventually reaches a non-equilbrium stationary state with a characteristic distribution of cluster sizes. The typical cluster size scales with the turnover rate and depends on how the diffusive mobility of clusters varies with their sizes. Lateral desorption of scaffold molecules can give rise to a critical size below which clusters dissolve, thus favoring a bimodal distribution of synapse sizes. The results provide a basis for the stability of clusters in the face of molecular noise, which is a necessary requirement for long-term memory and learning.

Date/Time : 27/01/2015 - 11:00 - 12:00

Location : LPTMS, salle 201, 2ème étage, Bât 100, Campus d'Orsay

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