In GPI anchoring, what is the nature of the bond between the protein and the lipid?
Glycosylphosphatidylinositol anchoring provides mode of attaching otherwise soluble proteins to extracellular face of plasma membrane. Biosynthesis in endoplasmic reticulum assembles GPI precursor containing phosphatidylinositol with two acyl chains inserted in lumenal leaflet, glucosamine, three mannoses and phosphoethanolamine moieties. Transamidase complex cleaves C-terminal GPI signal peptide at omega site and forms amide bond between new C-terminal carboxyl and amine of terminal ethanolamine phosphate which is glycosidically linked to mannose alpha1-2-mannose core. Further glycosidic bond
Ref: Kinoshita, J Lipid Res 2020, GPI anchor structure; Fujita & Kinoshita 2012.
