Mammals possess two genes encoding for Staufen1 (Stau1) and Staufen2 (Stau2), which are double-stranded-RNA-binding proteins. In previous studies, three Stau2 isoforms with molecular weights of 62 kDa, 59 kDa, and 52 kDa have been identified. Stau2 is mainly expressed in nervous system, while Stau1 is expressed more ubiquitously. The Staufen proteins are localized in the somatodendritic domain of neurons and play important roles in dendritic mRNA targeting. Stau2 was shown to shuttle between the nucleus and the cytoplasm. In order to identify the mRNA targets of Staufen proteins, we used the mRNP immunoprecipitation (RIP) technology was employed and identified distinct but overlapping subsets of cellular mRNAs associated with Stau1- and Stau2-containing ribonucleoprotein complexes.