DSRM (also known as dsRBM) is a 65-70 amino acid domain that adopts an alpha-beta-beta-beta-alpha fold. It is not sequence specific, but highly specific for double-stranded RNAs (dsRNAs) of various origin and structure. The DSRM domains are found in a variety of proteins including dsRNA dependent protein kinase PKR, RNA helicases, Drosophila Staufen protein, E. coli RNase III, RNase H1, and dsRNA dependent adenosine deaminases. They are involved in numerous cellular mechanisms ranging from localization and transport of messenger RNAs, through maturation and degradation of RNAs, to viral response and signal transduction. Some members harbor tandem DSRMs that act in small RNA biogenesis.