Fig 1. Schematic representation of the hTfR-EGFP chimera.

TfR is a type II transmembrane glycoprotein found primarily as a homodimer consisting of identical monomers joined by two disulfide bonds. Each monomer (760 amino acids) consists of three major domains as follows: a large glycosylated extracellular C-terminal domain (amino acids 90–760) involved in ligand binding, a single-pass transmembrane domain (amino acids 62–89), and a short intracellular N-terminal domain (amino acids 1–61). The EGFP moiety is fused to the amino terminus of hTfR.