ATP11B

ATP11B is a human gene encoding a member of the P4-ATPase family of phospholipid flippases. These enzymes are integral membrane proteins that use energy from ATP hydrolysis to move specific phospholipids from the outer to the inner leaflet of cellular membranes, helping establish and maintain phospholipid asymmetry.

In cells, ATP11B is thought to function as an aminophospholipid translocase, contributing to lipid asymmetry that supports vesicle formation and trafficking in the secretory and endocytic pathways. It is believed to act primarily in Golgi and endosomal membranes, although some evidence indicates plasma membrane localization in certain cell types.

ATP11B activity depends on non-catalytic CDC50 family proteins, such as CDC50A, for proper stability, trafficking, and function. The ATP11B-CDC50 complex forms a flippase that translocates phospholipids across membranes, supporting membrane curvature, vesicle formation, and trafficking processes.

Expression of ATP11B has been detected in multiple human tissues and is subject to developmental and environmental regulation. The precise patterns of expression and regulation can vary by cell type and context.

Clinical significance: There is currently limited established evidence linking ATP11B to specific human diseases. Some studies in cells or model organisms explore roles in membrane trafficking and phospholipid distribution, but robust disease associations remain to be defined as research continues.

See also: P4-ATPases; CDC50 family. References to entries in UniProt and NCBI Gene provide additional details on sequence, structure, and expression.