| Type: | Family | Name: | Inositol monophosphatase, Lithium-sensitive |
| Description: | It has been shown that several proteins share two sequence motifs []. Two of theseproteins, vertebrate and plant inositol monophosphatase (), and vertebrate inositol polyphosphate 1-phosphatase (), are enzymes of the inositol phosphate second messenger signalling pathway, and share similar enzyme activity. Both enzymes exhibit an absolute requirementfor metal ions (Mg2+is preferred), and their amino acid sequences contain a number of conserved motifs, which are also shared by several other proteins related to MPTASE (including products of fungal QaX and qutG, bacterial suhB and cysQ, and yeast hal2) []. The function of theother proteins is not yet clear, but it is suggested that they may act by enhancing the synthesis or degradation of phosphorylated messenger molecules []. Structural analysis of theseproteins has revealed a common core of 155 residues, which includes residues essential for metal binding and catalysis. An interesting property of the enzymes of this family is their sensitivityto Li+. The targets and mechanism of action of Li+are unknown, but overactive inositol phosphate signalling may account for symptoms of manic depression [].An interesting property of the enzymes of this family is their sensitivity to Li+ at levels achieved in patients undergoing therapy for manicdepression. The targets and mechanism of action of Li+ are unknown, but overactive inositol phosphate signalling may account for symptoms of thedisease [, ]. It has been proposed that these Li+-sensitive proteins could represent targets for Li+ in manic depressive disease [, , ]. | Short Name: | Inositol_monoPase_Li-sen |
