Cleaves a beta-phosphate from the diphosphate groups in PP-InsP5 (diphosphoinositol pentakisphosphate) and [PP]2-InsP4 (bisdiphosphoinositol tetrakisphosphate), suggesting that it may play a role in signal transduction ( ). InsP6 (inositol hexakisphosphate) is not a substrate . Acts as a negative regulator of the ERK1/2 pathway (By similarity). Also able to catalyze the hydrolysis of dinucleoside oligophosphates, with diadenosine 5',5'''-P1,P6-hexaphosphate (Ap6A) and diadenosine 5',5'''- P1,P5-pentaphosphate (Ap5A) being the preferred substrates (, ). The major reaction products are ADP and p4a from Ap6A and ADP and ATP from Ap5A . Also able to hydrolyze 5-phosphoribose 1-diphosphate . Acts as a decapping enzyme that modulates the stability of a subset of mRNAs implicated in cell motility . Hydrolyzes monomethylated capped RNA after both the alpha- and beta-phosphates generating m7GMP + ppRNA and m7GDP + pRNA . Can hydrolyze unmethylated capped RNAs (By similarity). Divalent cations zinc, magnesium and manganese determine its substrate specificity . Exhibits diphosphoinositol polyphosphate phosphohydrolase in the presence of magnesium ions, diadenosine hexaphosphate hydrolase activity in the presence of manganese ions and endopolyphosphatase activity in the presence of zinc ions . Plays an important role in limiting DNA damage and maintaining cell survival upon oxidative stress via its endopolyphosphatase activity .
Subcellular locations: Cytoplasm, Nucleus
Widely expressed. Expressed at higher level in brain, heart, pancreas and liver. Also expressed in placenta, lung and kidney.