This gene encodes a member of the histidine triad family of pyrophosphatases that removes short mRNA fragments containing the 5′ mRNA cap structure, which appear in the 3′ → 5′ mRNA decay pathway, following deadenylation and exosome-mediated turnover. This enzyme hydrolyzes the triphosphate linkage of the cap structure (7-methylguanosine nucleoside triphosphate) to yield 7-methylguanosine monophosphate and nucleoside diphosphate. It protects the cell from the potentially toxic accumulation of these short, capped mRNA fragments, and regulates the activity of other cap-binding proteins, which are inhibited by their accumulation. It also acts as a transcript-specific modulator of pre-mRNA splicing and microRNA turnover