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 (PubMed:23146885). Interacts with ATG9A (PubMed:30917996). 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. Widely expressed. Highest expression is observed in kidney, brain, heart, skeletal muscle, and placenta and lowest expression is observed in colon, thymus, and small intestine. Palmitoylated by ZDHHC3 and ZDHHC7 in the CCPCC motif. Palmitoylation is cholesterol-dependent, and required for TGN localization. Ubiquitinated by ITCH; this does not lead to proteasomal degradation. Belongs to the PI3/PI4-kinase family. Type II PI4K subfamily.