CPEB3 (cytoplasmic polyadenylation element binding protein 3) is a sequence-specific RNA-binding protein that serves as a critical regulator of synaptic plasticity and memory formation. CPEB3 functions as a translational switch, acting as a repressor in the basal state but becoming a translational activator following neuronal stimulation 1. The protein regulates translation of key synaptic proteins including AMPA receptor subunits (GRIA1, GRIA2), NMDA receptor subunits (GRIN1, GRIN2A, GRIN2B), and scaffolding proteins like PSD95, which are essential for synaptic plasticity and long-term memory consolidation 1. CPEB3 contains a self-cleaving ribozyme in its second intron that affects episodic memory performance 2. Structurally, the protein features an amyloid-forming segment (L103-F151) that is crucial for proper cellular localization and function, as deletion of this region results in abnormal cellular puncta formation and loss of translational control 3. CPEB3 demonstrates neuroprotective properties, with its deletion protecting against excitotoxicity and neuroinflammation in experimental models 4. In epilepsy, CPEB3 functions as a negative regulator of seizure susceptibility by inhibiting STAT3 transcriptional activity and subsequently reducing NMDAR expression 5. The protein also plays important roles in cancer suppression, particularly in hepatocellular carcinoma, by suppressing translation of oncogenic targets like MTDH 6.