Syntaxin 9 is Enriched in Skin Hair Follicle Epithelium and Interacts With the Epidermal Growth Factor Receptor

The study identified a novel syntaxin family member, syntaxin 9 (Syn 9), which lacked a typical C-terminal hydrophobic tail anchor but contained a Q-SNARE domain and showed homology to syntaxin 11. Syn 9 was enriched in epithelial cells, particularly in the stomach lining and skin, including structures associated with hair follicles. It specifically interacted with the epidermal growth factor (EGF) receptor, and its overexpression disrupted EGF receptor endocytosis without affecting transferrin receptor internalization. This suggested that Syn 9 played a role in EGF receptor transport and signaling in certain epithelial cells.