{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n ATP11A is a multifunctional member of the P4‐ATPase family that plays a key role in maintaining plasma membrane lipid asymmetry. By catalyzing the ATP‐dependent “flipping” of aminophospholipids—specifically translocating phosphatidylserine (PS) and phosphatidylethanolamine (PE) from the exoplasmic to the cytoplasmic leaflet—ATP11A upholds membrane integrity and regulates lipid homeostasis."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Functional studies have revealed that mutations in ATP11A can alter its substrate specificity. For example, a de novo point mutation (resulting in an amino acid substitution in a transmembrane segment) switches its activity so that it aberrantly flips phosphatidylcholine (PC) rather than its usual substrates. This misregulation of lipid distribution disturbs the normal balance of phospholipids and sphingomyelin, thereby affecting cell growth, cholesterol homeostasis, and neurological function."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n In addition to its fundamental role in lipid translocation, genetic variants in and near the ATP11A locus have been associated with metabolic traits. Genome‐wide association studies have linked ATP11A with variations in glycated hemoglobin (HbA₁c) levels, implicating its influence on erythrocyte biology and hemoglobin glycation."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Moreover, dysregulation of ATP11A has emerged in diverse pathological settings. Mutations leading to haploinsufficiency of ATP11A have been identified in families with sensorineural hearing loss, suggesting that proper ATP11A activity is essential for maintaining cochlear cell integrity."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": " Elevated ATP11A expression levels in colorectal cancer tissues have also been correlated with enhanced tumor proliferation and metastasis, indicating a potential role in oncogenic cell cycle regulation."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": " Furthermore, alterations in ATP11A splicing patterns have been reported in the cardiac tissues of myotonic dystrophy patients, linking its misregulation to cardiac dysfunction."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Together, these findings demonstrate that ATP11A is not only indispensable for maintaining the critical asymmetry of membrane lipids but also participates in a range of cellular processes that impact metabolic regulation, auditory function, cancer progression, and cardiac physiology. Ongoing research into the molecular mechanisms governing ATP11A function may pave the way for targeted therapeutic approaches across multiple disease states.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Hiroyuki Takatsu, Masahiro Takayama, Tomoki Naito, et al. 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