Alpha-tocopherol transfer protein (α-TTP)

Alpha-tocopherol transfer protein (α-TTP) is a cytosolic lipid-binding protein predominantly expressed in the liver, encoded by the TTPA gene[2][9]. Its primary function is the selective binding and intracellular transport of alpha-tocopherol (the most biologically active form of vitamin E), facilitating its incorporation into plasma lipoproteins for systemic distribution and preventing its degradation[1][2][3][6][7][8]. Structurally, α-TTP contains CRAL-TRIO domains responsible for ligand binding[4], and cycling between open and closed conformations for alpha-tocopherol loading and release[6][8]. Loss-of-function mutations in TTPA cause the inherited disorder ataxia with vitamin E deficiency (AVED), characterized by progressive neurodegeneration due to systemic vitamin E deficiency despite adequate intake[1][4][6][8][9]. Beyond vitamin E homeostasis, α-TTP may influence immune responses, antioxidant defense, cell signaling, and regulation of metabolic genes[3][5], implicating it in wider biological and disease processes. No drugs are approved that directly target α-TTP, but therapies affecting vitamin E status or its supplementation depend indirectly on its function[2][3][5][9].

Other names

Alpha-TTPTTPATPP1AVED proteintocopherol (alpha) transfer proteinalpha tocopherol transfer proteinATTP

Drugs or therapies modulating this target would act by enhancing or inhibiting alpha-tocopherol transport, altering vitamin E retention and distribution in tissues