Inositol Phosphatases

Inositol lipids are important intracellular second messengers. Inositol phosphatases remove phosphate groups from inositol lipids and are involved in the phosphatidylinositol signaling pathway. Two examples of inositol phosphatases are Ins(1,4,5)P₃ 5-phosphatase (E.C. 3.1.3.36) and inositol monophosphatase (IMPase) (E.C. 3.1.3.25).

Ins(1,4,5)P₃ 5-phosphatase catalyzes the specific dephosphorylation of Ins(1,4,5)P₄ in the 5 position to form Ins(1,3,4)P₃. This enzyme requires Mg²⁺ for catalytic activity and is found in almost all tissues.

IMPase is essential for the de novo synthesis of myo-inositol, and for recycling of Ins(1,4,5)P₃. IMPases are regulated in response to the metabolic need of inositol lipids. Structurally, IMPase exists as a homodimer that requires two metal cations (Mn²⁺ or Ca²⁺) for catalytic activity. The human IMPase 2 gene has been localized to chromosome 18p11.2 and this has been identified as a susceptibility region for bipolar disorder, schizophrenia and febrile seizures.

External sources of pharmacological information for Inositol Phosphatases :

• BJP Guide

Inositol Phosphatase Gene Data