Catalyzes the transfer of phosphatidylinositol and phosphatidylcholine between membranes (in vitro). Binds calcium ions. Interacts with PTK2B via its C-terminus (PubMed:10022914). Interacts with CPNE4 (via VWFA domain) (By similarity). Highly expressed in brain, heart, ovary, testis and thymus. Detected in small intestine, prostate, pancreas, skeletal muscle, liver, colon and placenta. Belongs to the PtdIns transfer protein family. PI transfer class IIA subfamily.