Phosphorylates phosphatidylinositol (PI) in the first committed step in the production of the second messenger inositol-1,4,5,-trisphosphate (PIP). May regulate Golgi disintegration/reorganization during mitosis, possibly via its phosphorylation. Involved in Golgi-to-plasma membrane trafficking (By similarity) (PubMed:10559940, PubMed:11277933, PubMed:12749687, PubMed:9405935). May play an important role in the inner ear development. ; (Microbial infection) Plays an essential role in Aichi virus RNA replication (PubMed:22124328, PubMed:22258260, PubMed:27989622). Recruited by ACBD3 at the viral replication sites (PubMed:22124328, PubMed:27989622). ; (Microbial infection) Required for cellular spike-mediated entry of human coronavirus SARS-CoV.