Involvement of the proteasome and caspase activation in hippocampal long-term depression induced by the serine protease subtilisin

► The serine protease subtilisin induced hippocampal LTD with a non-classical modification of caspase-3 and caspase-9. ► Late subtilisin LTD is reduced by the proteasome inhibitor MG132. ► Proteasomal inhibition reduces immediate LTP but increases late LTP and promotes LTP saturation. ► Proteasomal activity contributes to late subtilisin LTD and normal LTP.