SEC14-like lipid-binding protein (SEC14L)

SEC14-like vitamin E transport proteins, primarily represented by the SEC14L family and alpha-tocopherol transfer protein (TTPA), are essential intracellular transporters that manage the distribution of lipophilic antioxidants and lipids. These proteins are defined by the presence of a SEC14 (or CRAL-TRIO) domain, which forms a specialized hydrophobic pocket capable of sequestering and transferring molecules like alpha-tocopherol and squalene between cellular membranes. TTPA is the most critical member for systemic vitamin E homeostasis, as it facilitates the secretion of alpha-tocopherol from the liver into the bloodstream. Other members, such as SEC14L2 (also known as tocopherol-associated protein 1 or supernatant protein factor), play diverse roles including the stimulation of cholesterol biosynthesis and acting as tumor suppressors in various cancers. Mutations in these proteins, particularly TTPA, are linked to severe neurodegenerative disorders such as ataxia with vitamin E deficiency (AVED). Due to their central role in lipid signaling and antioxidant protection, they are subjects of research in oncology, infectious diseases like Hepatitis C, and metabolic disorders.

Other names

SEC14-like vitamin E transport proteinTocopherol-associated proteinTAPSupernatant protein factorSPFCRAL-TRIO domain-containing proteinAlpha-tocopherol transfer protein

Facilitates the intracellular transport and exchange of lipophilic ligands, such as alpha-tocopherol and squalene, between membranes; also acts as a co-factor or stimulator for enzymes like squalene monooxygenase and can modulate gene expression upon ligand binding.