MerTK is a member of a receptor tyrosine kinase (RTK) family that also includes AXL and TYRO3. Family members undergo ligand-induced homodimerization, followed by catalytic tyrosine kinase activation and intracellular signaling (1–4). Cross-phosphorylation has also been demonstrated within this RTK family, suggesting heterodimerization (5). These RTKs are widely expressed in many epithelial tissues and in cells of the immune, nervous, and reproductive systems (2, 6). The MerTK ligands include growth arrest-specific 6 (GAS6) (7, 8), protein-S (9, 10), tubby and tubby-like protein-1 (TULP1) (11), and galectin-3 (12). Several of these ligands are present in serum, and all ar
来源： J Clin Invest.