Glycosylphosphatidylinositols (GPIs) are lipid anchors allowing the exposure of 
proteins at the outer layer of the plasma membrane. In fungi, a number of 
GPI-anchored proteins (GPI-APs) are involved in the remodeling of the cell wall 
polymers. GPIs follow a specific biosynthetic pathway in the endoplasmic 
reticulum. After the transfer of the protein onto the GPI-anchor, a lipid 
remodeling occurs to substitute the diacylglycerol moiety by a ceramide. In 
addition to GPI-APs, A. fumigatus produces a GPI-anchored polysaccharide, the 
galactomannan (GM), that remains unique in the fungal kingdom. To investigate 
the role of the GPI pathway in the biosynthesis of the GM and cell wall 
organization, the deletion of PER1-coding for a phospholipase required for the 
first step of the GPI lipid remodeling-was undertaken. Biochemical 
characterization of the GPI-anchor isolated from GPI-APs showed that the PER1 
deficient mutant produced a lipid anchor with a diacylglycerol. The absence of a 
ceramide on GPI-anchors in the Δper1 mutant led to a mislocation of GPI-APs and 
to an alteration of the composition of the cell wall alkali-insoluble fraction. 
On the other hand, the GM isolated from the Δper1 mutant membranes possesses a 
ceramide moiety as the parental strain, showing that GPI anchor of the GM follow 
a distinct unknown biosynthetic pathway.