[Seminar] "Synaptic Machinery for Protein Turnover" by Prof. Chao Sun, Aarhus University, Denmark

Prof. Chao Sun

Associate professor, Department of Molecular Biology and Genetics
Group leader, Danish Research Institute of Translational Neuroscience (DANDRITE)- Nordic EMBL Partner for Molecular Medicine
Aarhus University, Denmark

Talk title: Synaptic Machinery for Protein Turnover

Abstract:
An individual neuron can host over 10000 synapses in its expansive dendritic and axonal arbor. To support parallel information processing, major cell-biological machineries are decentralized to individual synapses, including the machinery for protein turnover. To measure the local protein-synthesis and -degradation capacity, my recent works counted the copy numbers of dendritic ribosomes and proteasomes via single-molecule localization microscopy. In combination with metabolic labeling and single-spine plasticity induction, we reveal the spatial specificity of activity-induced local protein synthesis. The single-molecule resolution further affords quantitative mapping of different proteasome assembly states and reveals a surprising abundance of free regulatory particles 19S in dendrites. These 'solitary' dendritic proteasome regulatory particles regulate synaptic transmission via atypical ubiquitin signaling of key synaptic proteins such as AMPA receptors. As such, synapses can use alternative machine formats to carry out different functions, akin to protein ‘moonlighting’. Ongoing work in my lab is now looking into the synapse-specific regulation of protein turnover.