Description
INPP4A is a magnesium-independent phosphatase involved in the phosphatidylinositol 3-kinase (PI3K) pathway. INPP4A and its isoenzyme INPP4B hydrolyze the 4-phosphate from the lipid second messenger phosphatidylinositol-3,4-bisphosphate (PI(3,4)P2) to form phosphatidylinositol-3-phosphate (PI(3)P). While little evidence supports its role as a tumor suppressor, INPP4A suppresses glutamate excitotoxicity in the central nervous system and is responsible for the Weeble mouse phenotype. A spontaneous frame shift mutation in the Inpp4a gene is present in the Weeble mouse resulting in selective neuronal loss in the cerebellum resulting, severe ataxia and early death. The INPP4 ELISA is a competitive assay in which the signal is inversely proportional to the amount of PI(3)P produced. After the INPP4 reactions are complete, reaction products are added to the PI(3)P-coated microplate for competitive binding to a PI(3)P detector protein. The amount of PI(3)P detector protein bound to the plate is determined through colorimetric detection. The assay displays excellent robustness (Z' value ~ 0.8)