This superfamily represents a domain found in inositol polyphosphate 1-phosphatase INPP1 from animals. INPP1 is involved in the inositol phosphate second messenger signalling pathway. It has a core of 155 residues, which includes residues essential for metal binding and catalysis. An interesting property of the enzymes of this superfamily is their sensitivity to Li+. The targets and mechanism of action of Li+ are unknown, but overactive inositol phosphate signalling may account for symptoms of manic depression [].
