Characterization of two genes, Impa1 and Impa2 encoding mouse myo-inositol monophosphatases

Alon Shamir, Gry Sjøholt, Richard P. Ebstein, Galila Agam, Vidar M. Steen

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


The enzyme myo-inositol monophosphatase (Impa) catalyzes the synthesis of free myo-inositol from various myo-inositol monophosphates in the phosphatidylinositol signaling system. Impa is a lithium-blockable enzyme that has been hypothesized to be the biological target for lithium-salts used as mood-stabilizing drugs in the treatment of manic-depressive (bipolar) illness. As an initial step to explore the functional consequences of reduced or absent Impa activity in an animal model we here report the isolation of two Impa-encoding mouse genes, Impa1 and Impa2. Impa1 spans approximately 17.5 kb and contains nine exons of 46-1354 bp encoding a protein of 277 amino acids. Impa2 spans at least 19.5 kb and contains eight exons of 46-444 bp size encoding a protein of 290 amino acids. The genomic structure including the positions of the exon-intron splice sites seems to be conserved among myo-inositol monophosphatase genes in mammalian species. One or more Impa-like genes do also exist in evolutionary more distant species like invertebrates, plants and bacteria. The proteins encoded by the non-vertebrate genes seem to be equally related to Impa1 and Impa2. We therefore suggest that the Impa1 and Impa2 genes duplicated from a common ancestral gene after the evolutionary divergence of vertebrates.

Original languageEnglish
Pages (from-to)285-291
Number of pages7
Issue number2
StatePublished - 27 Jun 2001


  • Genomic characterization
  • Inositol monophosphatase (IMPA)
  • Mouse

ASJC Scopus subject areas

  • Genetics


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