Catalyzes the transfer of phosphatidylinositol (PI) and phosphatidylcholine (PC) between membranes (PubMed:8049244). Shows a preference for PI and PC containing shorter saturated or monosaturated acyl chains at the sn-1 and sn-2 positions (By similarity). Preference order for PC is C16:1 > C16:0 > C18:1 > C18:0 > C20:4 and for PI is C16:1 > C16:0 > C18:1 > C18:0 > C20:4 > C20:3 (By similarity). a 1,2-diacyl-sn-glycero-3-phosphocholine(in) = a 1,2-diacyl-sn-glycero-3-phosphocholine(out) a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol)(in) = a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol)(out) Phosphorylated by PKC in a calcium and phosphatidylserine-dependent manner. Defects in Pitpna are the cause of the vibrator phenotype which is characterized by early-onset progressive action tremor, degeneration of brain stem and spinal cord neurons, and juvenile death. The mutation is due to the insertion of an intracisternal A particle retrotransposon in intron 4 which results in a 5-fold reduction in protein levels. Belongs to the PtdIns transfer protein family. PI transfer class I subfamily.