Enables phosphatidylinositol-4,5-bisphosphate 3-kinase activity. Predicted to be involved in inositol phosphate biosynthetic process; inositol trisphosphate metabolic process; and necroptotic process. Predicted to act upstream of or within neural tube formation. Located in nucleus. Orthologous to human IPMK (inositol polyphosphate multikinase). [provided by Alliance of Genome Resources, Apr 2022]