Mer protein is a receptor tyrosine kinase that transduces signals by binding to ligands such as LGALS3, TUB, TULP1, or GAS6, regulating cell survival, migration, differentiation, and apoptotic cell phagocytosis (endocytosis) . Ligand binding induces autophosphorylation of MERTK, creating a docking site for downstream molecules. Mer Protein, Human (HEK293) is the recombinant human-derived Mer protein, expressed by HEK293 , with tag free.