Receptor topography and classification Cell surface receptors (shown as enzyme-linked receptor with intrinsic enzymatic activity） 市 3 TRE Nuclear receptors Gene (ligand-dependent transcriptional ↑or↓Gene expression regulators) Receptor topography and classification EGF receptor Nicotinic AchR o(outside) i(inside) Transferrin IAP(CD47). receptor(CD71) and GPCRs S.J.Singer(1990.Ann Rev Cell Biol 6:247)Nuclear receptors (ligand-dependent transcriptional regulators) Cell surface receptors (shown as enzyme-linked receptor with intrinsic enzymatic activity) Receptor topography and classification (outside) (inside) EGF receptor Transferrin receptor (CD71) IAP (CD47), and GPCRs Nicotinic AchR S.J. Singer (1990, Ann Rev Cell Biol 6:247) Receptor topography and classification