Vincent Hakim (ENS, Laboratoire de Physique Statistique)

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2 juillet 11:30 » 12:30 — Bibliothèque PCT - F3.04

Life and death in a floating world : the memorable case of synaptic domains

Synapses mediate transmission of information between neurons and are generally thought to be the support of memory. When investigated at the molecular scale, synapses appear as dynamic assemblies, with constituents exchanged on timescales shorter than a few tens of minutes. This raises fundamental questions about the way memory is maintained. On the post-synaptic side, the insertion of main synaptic components, neuro-transmitter receptors and synaptic scaffolding proteins, is likely to occur outside the post-synaptic domains. Advances in single-molecule imaging have shown that proteins diffuse in the plane of the membrane prior to their accumulation at synapses.

I will describe our theoretical analysis of the formation of post-synaptic domains motivated by these observations and original data from the Triller lab (IBENS). In particular, our results and new superesolution data suggest the existence of extrasynaptic clusters with a characteristic steady-state size distribution maintained by a non-equilibrium balance between aggregation of diffusing protein clusters and turnover. We predict that extrasynaptic clusters significantly contribute to the size fluctuations of synaptic domains and we estimate their lifetime in the proposed framework.





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