Probable phospholipid-transporting ATPase IF (ATP11B) (ATP11B)

Probable phospholipid-transporting ATPase IF (ATP11B) is a member of the P4-ATPase family that functions as a flippase, translocating phospholipids like phosphatidylserine from the outer to the inner leaflet of cell membranes to maintain lipid asymmetry (UniProt: Q9Y2G3; GeneCards: ATP11B). Beyond its physiological role in membrane trafficking, ATP11B is a critical mediator of resistance to platinum-based chemotherapy, particularly cisplatin (PubMed: 23838066). In various cancers, including ovarian and colorectal, ATP11B is overexpressed and facilitates the sequestration of cisplatin into secretory vesicles, which are then trafficked out of the cell (PubMed: 21642682). This efflux mechanism reduces the amount of drug reaching the nucleus, thereby diminishing DNA damage and allowing cancer cells to survive treatment (PubMed: 23838066). Consequently, ATP11B mRNA and its protein product are being investigated as therapeutic targets to sensitize resistant tumors to chemotherapy. While no direct inhibitors are currently in clinical use, experimental silencing of ATP11B has been shown to restore drug sensitivity in preclinical models (PubMed: 21642682).

Other names

ATPase class VI type 11BATPIFP4-ATPaseATP11B mRNAATPase 11BPhospholipid-transporting ATPase IF

ATP11B facilitates the sequestration of platinum-based drugs into secretory vesicles, thereby promoting their efflux and reducing intracellular toxicity; its inhibition restores drug sensitivity by increasing nuclear drug accumulation.