IMPA1
IMPA1 (inositol monophosphatase 1, also known as IMPA) is a cytoplasmic phosphatase that dephosphorylates myo-inositol monophosphates to release free myo-inositol. It supplies the inositol needed for phosphatidylinositol synthesis and is a recognised pharmacological target of lithium. Browse Assay Genie's current range of IMPA1 research reagents below, or read on for the biology behind the target.
IMPA1 is a phosphatase that dephosphorylates myo-inositol monophosphates to generate myo-inositol. Free inositol is a precursor of phosphatidylinositol, so the enzyme provides the inositol required for the synthesis of phosphatidylinositols and polyphosphoinositides. Through this role it modulates intracellular signal transduction, including production of the second messengers myo-inositol 1,4,5-trisphosphate and diacylglycerol, and it is involved in maintaining normal brain function. Its activity is magnesium-dependent.
Beyond myo-inositol monophosphates, IMPA1 can dephosphorylate scyllo-inositol-phosphate, myo-inositol 1,4-diphosphate, scyllo-inositol-1,3-diphosphate and scyllo-inositol-1,4-diphosphate. In vitro it also acts on other sugar phosphates, including D-galactose-1-phosphate, glucose-1-phosphate, glucose-6-phosphate, fructose-1-phosphate, beta-glycerophosphate and 2'-AMP. It is equally active with 1D-myo-inositol 1-phosphate, 1D-myo-inositol 3-phosphate and D-galactose 1-phosphate. The protein belongs to the inositol monophosphatase superfamily and is found in the cytoplasm. The human IMPA1 gene is classed by HGNC among the phosphoinositide phosphatases, and mouse and rat each carry an orthologous Impa1 gene. Alternative splicing produces multiple transcript variants encoding distinct isoforms, and a pseudogene lies on the same chromosomal band.
IMPA1 is inhibited by therapeutic concentrations of lithium. Inhibiting inositol monophosphate hydrolysis and so depleting inositol for phosphatidylinositol synthesis may explain the anti-manic and anti-depressive effects of lithium in bipolar disorder, which is why the enzyme is widely studied as the pharmacological target of lithium action in brain. HGNC lists the previous name inositol(myo)-1(or 4)-monophosphatase 1 and the previous symbol IMPA. A related enzyme, IMPA2, belongs to the same superfamily.
IMPA1 regenerates free inositol for phosphatidylinositol synthesis, making it central to studies of inositol recycling and second messenger production.
As a lithium-inhibited enzyme, IMPA1 is used to study how inositol depletion may underlie the effects of lithium in bipolar disorder.
IMPA1 is involved in maintaining normal brain function, so it is investigated in work on inositol supply and neuronal signalling.
IMPA1 acts on inositol phosphates and other sugar phosphates, making it a useful model for magnesium-dependent phosphatase activity.
IMPA1 dephosphorylates myo-inositol monophosphates to generate free myo-inositol, which is needed for synthesis of phosphatidylinositols and polyphosphoinositides. Through this it influences signalling via inositol 1,4,5-trisphosphate and diacylglycerol, and it contributes to normal brain function.
IMPA1 is also known by the previous symbol IMPA and the previous name inositol(myo)-1(or 4)-monophosphatase 1. The systematic name is inositol monophosphatase 1. Alternative splicing of the IMPA1 gene gives multiple transcript variants that encode distinct isoforms.
IMPA1 is inhibited by therapeutic concentrations of lithium. The resulting block in inositol monophosphate hydrolysis may deplete inositol for phosphatidylinositol synthesis, which may explain the anti-manic and anti-depressive effects of lithium. Mouse and rat Impa1 orthologs exist; check the datasheet of any product for its validated reactivity.
Other inositol monophosphatases and phosphoinositide pathway targets with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P29218; product specifications from Assay Genie datasheets.