Required for transport of secretory proteins from the Golgi complex. Catalyzes the transfer of phosphatidylinositol (PI) and phosphatidylcholine (PC) between membranes in vitro. Essential for viability and secretion (PubMed:2466847, PubMed:2215682). Exchanges its bound phospholipid with phospholipid monomers that reside in membrane bilayers (PubMed:16997918). Regulates specific trans-Golgi export pathways, like transport from endosomes to the trans-Golgi or transport from the plasma membrane to the vacuole at the level of the endosome (PubMed:19129178). Increased membrane curvature and lipid unsaturation levels at the trans-Golgi membrane promotes membrane binding and phospholipid transfer of SEC14. Thus, SEC14 may act at the trans-Golgi membrane to exchange lipids and promote vesicle formation (PubMed:32828847). The phosphatidylcholine-bound form of SEC14 represses the CDP-choline pathway activity by inhibiting CCTase, the rate-determining enzyme of the CDP-choline pathway (PubMed:7816798). PI binding/transfer is dispensable for function in vivo (PubMed:10488334). Required for trafficking and localization of lipid raft proteins to the plasma membrane (PubMed:23383173). a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol)(in) = a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol)(out) a 1,2-diacyl-sn-glycero-3-phosphocholine(in) = a 1,2-diacyl-sn-glycero-3-phosphocholine(out) The inhibitor activity of SEC14 is controlled by whether PI or PC is bound to SEC14. The pPC-bound form of SEC14 is an inhibitor, while the PI-bound form is not. The phospholipid binding/exchange activity of SEC14 represents a mechanism by which the regulatory activity of SEC14 is itself controlled. Present with 84300 molecules/cell in log phase SD medium.