Revealing Acute Consequences of Rapid Protein Elimination at Individual Synapses using Auxin-Inducible Degron 2 Technology

A powerful approach to assess a protein of interest (POI) function is its specific elimination. Common knock-out and knock-down strategies, however, are protracted and often irreversible, challenging the assessment of acute or temporary consequences in the same cells and tissues. Here we describe the use of Auxin-Inducible Degron 2 (AID2) technology to study the real-time consequences of acute POI elimination in nerve cell synapses. We demonstrate its capacity in cultured neurons and in vivo to rapidly eliminate postsynaptic scaffold proteins fused at N-terminal, C-terminal, or nested sites to GFP derivatives or HaloTag. We show that acute PSD-95 or gephyrin elimination leads to the concomitant loss of AMPA or GABA _A receptors at the same synapses, and that, surprisingly, acute GKAP, but not PSD-95 elimination reduces postsynaptic scaffold size. Our findings highlight the utility of AID2 technology for rapidly eliminating synaptic POIs and studying real-time consequences in the same neurons and synapses.