CPEB1 and cerebellar ataxia: Additionally, several lines of evidence suggest that CPEB1 is also important for cerebellar function; abnormally increased spine density, longer spines, abolished protein synthesis-dependent LTD, and ataxia were observed in the cerebellum in mice expressing CPEB1-AA that is a phosphorylation mutant and defective in exerting polyadenylation mediated-translation (McEvoy et al., 2007).