Calnexin or CNX is an integral protein that weighs 67kDa and is a part of the endoplasmic reticulum or ER. It consists of large N-T calcium linking lumenal domain, one transmembrane helix, and a small acidic cytoplasmic tail. Calnexin is characterized by studying the folding of protein and quality control.
It ensures that only properly folded and assembled proteins can proceed on the secretory pathway. It specifically works to keep unfolded N-bonded glycoproteins in the ER. Calnexin links only those N-glycoproteins that have oligosaccharides present in it. If you want to buy an anti-calnexin booster, hop over here.
These oligosaccharides are formed by cutting two glucose residues due to their rowing action of two glucosidases, I and II. Glucosidase number II also removes the third and last glucose residue present in the given sample. If the glycoprotein is not folded properly, then an enzyme called UGGT will put the glucose residue back into the oligosaccharide.
It gives rise to the regeneration of glycoprotein's ability to link to calnexin. The improperly-folded glycoprotein chain then moves around in the ER zone and the EDEM eventually makes the underperforming glycoprotein degrade by removing one of the mannose residues present in it. An Anti-calnexin antibody is used to measure calnexin present in the given sample.
The mannose lectin named Yos-9 or known as OS-9 in humans identifies, labels, and sorts misfolded glycoproteins for degradation to occur. Yos-9, then identifies mannose residues that are exposed after mannosidase gets removed from the outer mannose present in misfolded glycoproteins.