Membrane-bound phosphatidylinositol-4 kinase (PI4-kinase) that catalyzes the phosphorylation of phosphatidylinositol (PI) to phosphatidylinositol 4-phosphate (PI4P), a lipid that plays important roles in endocytosis, Golgi function, protein sorting and membrane trafficking and is required for prolonged survival of neurons. Besides, phosphorylation of phosphatidylinositol (PI) to phosphatidylinositol 4-phosphate (PI4P) is the first committed step in the generation of phosphatidylinositol 4,5-bisphosphate (PIP2), a precursor of the second messenger inositol 1,4,5-trisphosphate (InsP3). a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol) + ATP = a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol 4-phosphate) + ADP + H(+) Associates with the BLOC-1 and the AP-3 complexes; the BLOC-1 complex is required for optimal binding of PI4K2A to the AP-3 complex. Interacts with BLOC1S5 and DTNBP1 (PubMed:21998198). Interacts with FOS; this interaction may enhance phosphatidylinositol phosphorylation activity (By similarity). Interacts with ITCH (By similarity). Interacts with ATG9A (By similarity). Found in subdomains of the plasma membrane termed non-caveolar membrane rafts. Transported from neuronal cell body to neuron projections and neurite tips in a BLOC-1- and AP-3-complexes-dependent manner. Detected in adult brain, especially in neurons in the cerebellum, brain cortex, dorsal root ganglion and spinal cord (at protein level). Ubiquitinated by ITCH; this does not lead to proteasomal degradation. Palmitoylated (PubMed:11244087). Palmitoylated by ZDHHC3 and ZDHHC7 in the CCPCC motif. Palmitoylation is cholesterol-dependent, and required for TGN localization (By similarity). Belongs to the PI3/PI4-kinase family. Type II PI4K subfamily.