Component of a complex required to localize phosphatidylinositol 4-kinase (PI4K) to the plasma membrane. The complex acts as a regulator of phosphatidylinositol 4-phosphate (PtdIns(4)P) synthesis. HYCC1 plays a key role in oligodendrocytes formation, a cell type with expanded plasma membrane that requires generation of PtdIns(4)P. Its role in oligodendrocytes formation probably explains its importance in myelination of the central and peripheral nervous system. May also have a role in the beta-catenin/Lef signaling pathway