Atlantic Salmon (Salmo salar) Transforming Growth Factor Alpha (TGF-α) is a member of the epidermal growth factor (EGF) family of growth factors, which also includes epidermal growth factor (EGF), amphiregulin, betacellulin, epiregulin, and heparin-binding EGF-like growth factor (HB-EGF). In Atlantic salmon, TGF-α is synthesized as a membrane-bound precursor (pro–TGF-α) that is proteolytically cleaved to release a soluble ligand capable of binding the epidermal growth factor receptor (EGFR). Activation of EGFR stimulates intracellular signaling pathways such as MAPK/ERK, PI3K/AKT, and JAK/STAT, which regulate cell proliferation, differentiation, epithelial growth, and tissue regeneration. In salmon, TGF-α is expressed in tissues including the skin, gills, gastrointestinal tract, and developing organs, where it contributes to epithelial maintenance, mucosal barrier function, and tissue repair following injury or infection. Because epithelial surfaces such as the skin and gills are critical interfaces with the aquatic environment, TGF-α–mediated signaling plays an important role in barrier integrity and regeneration of damaged tissues. Characterization of Atlantic salmon TGF-α supports research on fish epithelial biology, wound healing, developmental processes, and host responses to environmental stress or pathogens, contributing to improved understanding of tissue regeneration and health in aquaculture species.