Sequence-specific RNA-binding protein which acts as a translational repressor in the basal unstimulated state but, following neuronal stimulation, acts as a translational activator (By similarity). Does not bind to the cytoplasmic polyadenylation element (CPE), a uridine-rich sequence element within the mRNA 3'-UTR, but binds to a U-rich loop within a stem-loop structure (By similarity). Required for the consolidation and maintenance of hippocampal-based long term memory (By similarity). Inhibits differentiation of intermediate mesoderm from an early stage to inhibit pronephric differentiation but induce neural differentiation (PubMed:18472403). Following synaptic activity, forms amyloid-like oligomers (By similarity). Aggregation requires an intact actin cytoskeleton (By similarity). Predominantly cytoplasmic in unstimulated neurons but translocates to the nucleus following neuronal stimulation. In embryos, expressed in the central nervous system, and intermediate and distal pronephric tubule segments of the embryonic kidney. The N-terminal Gln-rich region is required for the formation of amyloid-like oligomers and for the stability of long-term potentiation and spatial memory. Belongs to the RRM CPEB family.