IMPA1

This gene encodes an enzyme that dephosphorylates myo-inositol monophosphate to generate free myo-inositol, a precursor of phosphatidylinositol, and is therefore an important modulator of intracellular signal transduction via the production of the second messengers myoinositol 1,4,5-trisphosphate and diacylglycerol. This enzyme can also use myo-inositol-1,3-diphosphate, myo-inositol-1,4-diphosphate, scyllo-inositol-phosphate, glucose-1-phosphate, glucose-6-phosphate, fructose-1-phosphate, beta-glycerophosphate, and 2'-AMP as substrates. This enzyme shows magnesium-dependent phosphatase activity and is inhibited by therapeutic concentrations of lithium. Inhibition of inositol monophosphate hydroylosis and subsequent depletion of inositol for phosphatidylinositol synthesis may explain the anti-manic and anti-depressive effects of lithium administered to treat bipolar disorder. Alternative splicing results in multiple transcript variants encoding distinct isoforms. A pseudogene of this gene is also present on chromosome 8q21.13.

Full Name

Inositol Monophosphatase 1

Function

Responsible for the provision of inositol required for synthesis of phosphatidylinositol and polyphosphoinositides and has been implicated as the pharmacological target for lithium action in brain. Has broad substrate specificity and can use myo-inositol monophosphates, myo-inositol 1,3-diphosphate, myo-inositol 1,4-diphosphate, scyllo-inositol-phosphate, D-galactose 1-phosphate, glucose-1-phosphate, glucose-6-phosphate, fructose-1-phosphate, beta-glycerophosphate, and 2'-AMP as substrates.

Biological Process

Inositol biosynthetic processIEA:UniProtKB-UniPathway
Inositol metabolic processManual Assertion Based On ExperimentIBA:GO_Central
Inositol phosphate dephosphorylationManual Assertion Based On ExperimentIDA:UniProtKB
Phosphate-containing compound metabolic processManual Assertion Based On ExperimentIMP:UniProtKB
Phosphatidylinositol biosynthetic processManual Assertion Based On ExperimentIMP:UniProtKB
Phosphatidylinositol phosphate biosynthetic processIEA:InterPro
Signal transductionManual Assertion Based On ExperimentIMP:UniProtKB

Cellular Location

Cytoplasm

Involvement in disease

Mental retardation, autosomal recessive 59 (MRT59):
A form of mental retardation, a disorder characterized by significantly below average general intellectual functioning associated with impairments in adaptive behavior and manifested during the developmental period. MRT59 transmission pattern is consistent with autosomal recessive inheritance.