ATP8B1 and progressive familial intrahepatic cholestasis type 1: When Atp8b1 is not available to maintain the normal distribution of lipids between the two lipid layers in the plasma membrane, the canalicular membrane becomes too fragile to maintain its homeostasis [25], which leads to a pathological condition called progressive familial intrahepatic cholestasis type 1 (PFIC-1) [26].