Megalin in normal tissues and carcinoma cells carries oligo/poly alpha2,8 deaminoneuraminic acid as a unique posttranslational modification.

In rat kidney, megalin, a member of the low density lipoprotein receptor gene family, is the sole glycoprotein which carries oligo/poly alpha2,8 deaminoneuraminic acid (KDN) as a posttranslational modification. We have investigated immunoprecipitated megalin from rat brain, lung and placenta, mouse yolk sac carcinoma and megalin synthesizing carcinoma cell lines, for presence of this unique glycan structure. Our immunoblot analysis revealed the presence of oligo/poly alpha2,8 KDN on megalin in all the studied normal tissues and carcinoma cells. Furthermore, it is demonstrated to be part of oligosaccharides O-glycosidically linked to megalin.