biostudies-otherUnknownMs. Mizuki IshidaMEXT | Japan Society for the Promotion of Science (JSPS)Ministry of Health, Labour and Welfare (MHLW)Mizutani Foundation for Glycoscience (MFG)KOSE Cosmetology Research FoundationJapan Agency for Medical Research and Development (AMED)EMBO Reportshttps://www.ebi.ac.uk/biostudies/studies/S-SCDT-EMBOR-2021-54352V1Glycosylphosphatidylinositols (GPIs) are glycolipids that anchor many proteins (GPI-APs) on the cell surface. The core glycan of GPI precursor has three mannoses, which in mammals, are all modified by ethanolamine-phosphate (EthN-P). It is postulated that EthN-P on the third mannose (EthN-P-Man3) is the bridge between GPI and the protein and the second (EthN-P-Man2) is removed after GPI-protein attachment. However, EthN-P-Man2 may not be always transient, as mutations of PIGG, the enzyme that transfers EthN-P to Man2, result in inherited GPI deficiencies (IGDs), characterized by neuronal dysfunctions. Here, we show that EthN-P on Man2 is the preferential bridge in some GPI-APs, among them, the Ect-5'-nucleotidase and Netrin G2. We find that CD59, a GPI-AP, is attached via EthN-P-Man2 both biostudies-otherJP21H0241521ek0109418h0003JP17H06422Ms. Yoko TakadaDr. Yoshiko MurakamiDr. Philippe, M CampeauMs. Mizuki IshidaMr. Akinori NinomiyaDr. Yuta MakiDr. Taroh KinoshitafalseEthanolamine-phosphate on the second mannose is a preferential bridge for some GPI-anchored proteinsGlycosylphosphatidylinositols (GPIs) are glycolipids that anchor many proteins (GPI-APs) on the cell surface. The core glycan of GPI precursor has three mannoses, which in mammals, are all modified by ethanolamine-phosphate (EthN-P). It is postulated that EthN-P on the third mannose (EthN-P-Man3) is the bridge between GPI and the protein and the second (EthN-P-Man2) is removed after GPI-protein attachment. However, EthN-P-Man2 may not be always transient, as mutations of PIGG, the enzyme that transfers EthN-P to Man2, result in inherited GPI deficiencies (IGDs), characterized by neuronal dysfunctions. Here, we show that EthN-P on Man2 is the preferential bridge in some GPI-APs, among them, the Ect-5'-nucleotidase and Netrin G2. We find that CD59, a GPI-AP, is attached via EthN-P-Man2 both 2022-07-18T00:00:00Z2022-07-18T15:53:17.951Z2022-07-18T15:53:17.951ZS-SCDT-EMBOR-2021-54352V110.15252/embr.202154352