CPEB3 Protein, Human (His, Strep)

CPEB3 is a sequence-specific RNA-binding protein that functions as a translational repressor in the basal unstimulated state but switches to a translational activator following neuronal stimulation (By similarity). Unlike CPEB1, it does not bind the cytoplasmic polyadenylation element (CPE, a uridine-rich sequence in the mRNA 3'-UTR) but instead binds a U-rich loop within a stem-loop structure (By similarity). It is essential for the consolidation and maintenance of hippocampal-based long-term memory (By similarity). In the basal state, CPEB3 binds the 3'-UTR of GRIA2/GLUR2 mRNA and represses its translation (By similarity), while also suppressing the translation of DLG4, GRIN1, GRIN2A, and GRIN2B (By similarity). Upon activation, it promotes the translation of GRIA1 and GRIA2 (By similarity). It represses SUMO2 translation in the basal state but activates it after neuronal stimulation (By similarity). By binding the 3'-UTR of TRPV1 mRNA, it represses TRPV1 translation, which is required for normal thermoception (By similarity). It binds actin mRNA, repressing its translation basally and activating it post-stimulation (By similarity). Through interaction with TOB1, CPEB3 recruits CNOT7/CAF1 to form a ternary complex, leading to target mRNA deadenylation and decay (PubMed:21336257). Beyond translation regulation, CPEB3 binds and inhibits the transcriptional activation activity of STAT5B (without affecting dimerization or DNA binding), thereby repressing transcription of the STAT5B target gene EGFR, which enhances learning and memory (PubMed:20639532). Unlike CPEB1, CPEB2, and CPEB4, CPEB3 is not required for cell cycle progression (PubMed:26398195).