With the exception of Entamoeba proteophosphoglycan (PPG) (panel A), all known protein-linked GPI anchors have the same minimal core structure embellished with species- and tissue-specific side-chain and lipid variations. (±) Glycosyl heterogeneity; (curved arrows for the Saccharomyces examples in panel B) the two terminal αMan residues are mutually exclusive; (*) unknown lipid type or chain length. Chain lengths and degrees of unsaturation of the lipids are indicated. For the monosaccharide symbol code, see Online Appendix 1B. PSP, promastigote surface protease; VSG, variant surface glycoprotein; GARP, glutamic acid/alanine-rich protein; TS, trans-sialidase; VSA, variant surface antigen; GPI-APs, glycosylphosphatidylinositol-anchored proteins; PSA, prespore antigen; AGP, arabinogalactan protein; AChE, acetylcholinesterase; eAChE, erythrocyte acetylcholinesterase; MDP, metallodipeptidase; NCAM, neural cell adhesion molecule; PLAP, placental alkaline phosphatase.