Protein Glycosylation in Aspergillus fumigatus Is Essential for Cell Wall Synthesis and Serves as a Promising Model of Multicellular Eukaryotic Development

Figure 6

Schematic illustration of GPI biosynthesis in the ER of yeast and mammals. Biosynthesis of the GPI anchor begins at step 1; PI is glycosylated to generate GlcNAc-PI on the cytoplasmic face of the ER. GlcNAc-PI is then de-N-acetylated (step 2) to yield GlcN-PI. GlcN-PI is flipped (step 3) into the lumenal leaflet of the ER, where it is inositol acylated (step 4), inositol mannosylated, and modified by EtNP (steps 5–10). The EtNP-capped GPIs are attached (step 11) to ER-translocated proteins displaying a C-terminal GPI signal sequence. Step  11 is catalyzed by GPI transamidase.