Conserved Site

Inositol monophosphatase, conserved site (IPR020550)

Short name: Inositol_monophosphatase_CS


It has been shown that several proteins share two sequence motifs [PMID: 1660408]. Two of these proteins, vertebrate and plant inositol monophosphatase (EC:, and vertebrate inositol polyphosphate 1-phosphatase (EC:, are enzymes of the inositol phosphate second messenger signalling pathway, and share similar enzyme activity. Both enzymes exhibit an absolute requirement for 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) [PMID: 7761465]. The function of the other proteins is not yet clear, but it is suggested that they may act by enhancing the synthesis or degradation of phosphorylated messenger molecules [PMID: 1660408]. Structural analysis of these proteins 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 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 [PMID: 2553271].

This entry represents a conserved signature pattern found within the inositol monophosphatase family of proteins. It is suggested [PMID: 1660408] that these proteins may act by enhancing the synthesis or degradation of phosphorylated messenger molecules.

GO terms

Biological Process

GO:0046854 phosphatidylinositol phosphorylation

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns