Component of a complex required to localize phosphatidylinositol 4-kinase (PI4K) to the plasma membrane. Component of a phosphatidylinositol 4-kinase (PI4K) complex, composed of PI4KA, EFR3 (EFR3A or EFR3B), TTC7 (TTC7A or TTC7B) and FAM126 (FAM126A or FAM126B). Belongs to the FAM126 family.