ATPase phospholipid transporting 8B4 (ATP8B4)

ATPase phospholipid transporting 8B4 (ATP8B4) is a transmembrane enzyme and transporter belonging to the P4-ATPase family (type IV P-type ATPases). It uses ATP hydrolysis to catalyze the translocation ("flipping") of aminophospholipids from the outer to the inner leaflet of biological membranes, which is crucial for maintaining lipid asymmetry. This process is involved in essential cellular functions such as vesicle formation, signal transduction, and uptake of lipid signaling molecules. ATP8B4 is encoded on the human genome and has alternative splice variants. Dysfunction may be associated with intellectual disability and hepatic cholestasis. ATP8B4 functions as part of a larger flippase complex and interacts with accessory proteins for proper folding and activity. The substrate specificity of ATP8B4 is assumed similar to other ATP8B subfamily members (likely prefers phosphatidylcholine, but exact specificity awaits detailed biochemical confirmation).

Other names

Probable phospholipid-transporting ATPase IMATP8B4KIAA1939ATPIMATPase class I type 8B member 4P4-ATPase flippase complex alpha subunit ATP8B4putative phospholipid-transporting ATPase IM

For related P4-ATPases, inhibition disrupts phospholipid flipping, leading to altered membrane asymmetry and cell function. Specific mechanisms for ATP8B4-modulating drugs are not described