Polymeric Immunoglobulin Receptor Protein (recombinant human)

Activity: Measured by its binding ability in a functional ELISA.Immobilized rhhuman IgM at 2 µg/ml (100 µl/well) can bind biotinylated PIGR with a linear range of 0.94-15 ng/ml.2. When human human IgM is immobilized at 2 µg/ml (100 µl/well), PIGR inhibits 50% binding of biotinylated PIGR (0.062 µg/ml) at the concentration range of 0.03-20 µg/ml. Protein Construction: Recombinant Human Polymeric Immunoglobulin Receptor is produced by our Mammalian expression system and the target gene encoding Lys19-Arg638 is expressed with a 6His tag at the C-terminus. Sequence: Lys19-Arg638. Fusion tag: C-6His Endotoxin: < 1.0 EU per µg as determined by the LAL method. Apparent Molecular Mass: 88 kDa. Protein function: The human Polymeric Immunoglobulin Receptor (pIgR) is a 100 kDa type I transmembrane glycoprotein. Its precursor is 764 amino acids. It contains an 18 amino acid signal sequence, a 620 amino acid extracellular region, a 23 amino acid transmembrane fragment, and a 103 amino acid cytoplasmic domain. pIgR is synthesized by secretory epithelial cells with five Ig-like domains in extracellular region, and transfer to the basolateral plasma membrane. For IgA and IgM polymers, in addition to a-heavy chains and light Ig chains, a short polypeptide named joining chain (J chain) is also contained and required. pIgR can bind larger polymers of IgA (pIgA) and pentameric IgM as a carrier that transports IgA and IgM across epithelium. The receptor-ligand complexes are endocytosed and transcytosed to the apical surface, then proteolytic cleavage of the sixth extracellular domain of pIgR and generate secretory IgA (SIgA), the pIgR fragment is referred to as secretory component (SC). SIgA is a important component of the muco Protein function: This receptor binds polymeric IgA and IgM at the basolateral surface of epithelial cells. The complex is then transported across the cell to be secreted at the apical surface. During this process a cleavage occurs that separates the extracellular (known as the secretory component) from the transmembrane segment. [The UniProt Consortium]