Proteasome modulates positive and negative translational regulators in long-term synaptic plasticity

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• The ubiquitin-proteasome pathway's role in synaptic plasticity is complex and not fully understood.
• Previous studies showed proteasome inhibition enhances L-LTP induction but blocks maintenance.

Purpose of the Study:

• Investigate mechanisms behind proteasome inhibition's opposing effects on L-LTP induction and maintenance.
• Elucidate the interplay between proteolysis and protein synthesis signaling pathways.

Main Methods:

• Used mouse hippocampus late-phase long-term potentiation (L-LTP) model.
• Inhibited proteasome and key signaling molecules (PI3K, eIF4E/eIF4G interaction).
• Analyzed levels of translational activators and repressors during L-LTP.

Main Results:

• Inhibiting PI3K or eIF4E/eIF4G interaction reduced proteasome inhibition-enhanced L-LTP induction.
• Proteasome inhibition caused accumulation of translational activators (eIF4E, eEF1A) early in L-LTP.
• Proteasome inhibition led to buildup of translational repressors (Paip2, 4E-BP2) late in L-LTP, blocking maintenance.

Conclusions:

• The proteasome critically regulates protein synthesis during L-LTP by controlling translation.
• Novel insights into the interplay between protein degradation and synthesis in long-term synaptic plasticity.