PGAP2, also known as FRAG1, is involved in the lipid remodeling steps of glycosylphosphatidylinositol (GPI)-anchor maturation []. Immediately after attachment of GPI to newly synthesized proteins, inositol-linked palmitate is removed by deacylase PGAP1 in the ER. The inositol-deacylation is essential for subsequent steps in fatty acid remodeling in the Golgi. PGAP3 removes an unsaturated fatty chain at sn-2 and PGAP2 reacylation of sn-2 with stearic acid follows [].
This entry includes the PGAP2-interacting protein from mammals and the protein Cwh43 from yeasts.Cwh43 is involved in the maintenance of cell wall integrity. It is required for the replacement of the diacylglycerol moiety by ceramides during GPI (glycosylphosphatidylinositol) - anchor maturation [, , ]. The C-terminal region of Cwh43 is homologous to mammalian PGAP2-interacting protein (PGAP2IP), and is essential for the ability to remodel GPI lipids to ceramides. The N-terminal region of yeast Cwh43 contains a sequence homologous to mammalian PGAP2 (post-GPI attachment to proteins factor 2). The association of the the N-terminal region enhances the lipid remodelling to ceramides by the C-terminal region. Mammalian PGAP2 and PGAP2-interacting protein seems to share these activities [].
