PI4K

Four genes encode the human PI4-kinases that make phosphatidylinositol 4-phosphate: the type III enzymes PI4KA and PI4KB, and the type II enzymes PI4K2A and PI4K2B. PI4KB is anchored at the Golgi through interactions with ACBD3, Rab1 and Arf1 and supplies PI4P for lipid transfer and secretory trafficking. PI4KA works at the plasma membrane inside a complex with TTC7 and FAM126A that maintains PI(4,5)P2 pools, and mutations in those partners cause a neonatal leukodystrophy with gastrointestinal defects. PI4K2A and PI4K2B are membrane-integral kinases acting on endolysosomal compartments. Enteroviruses and hepatitis C virus hijack PI4KB to build replication organelles, making the family an antiviral target.