Attachment of Proteins to Membranes via Lipids
Trypanosoma brucei was a key player in the discovery of glycosylphosphatidylinositol (GPI) anchors: the first complete chemical structure of a GPI anchor was determined using the variant surface glycoprotein, the major surface protein of T. brucei bloodstream forms, as a model protein. In addition, the biosynthetic steps leading to the assembly of GPI anchors were first identified in T. brucei and provided the groundwork to establish these pathways in other cells.
GPI-anchored molecules in procyclic form trypanosomes
In addition, we discovered two novel GPI-anchored molecules in T. congolense procyclic forms, PRS and EPGENGT procyclin. While PRS may be a non-proteinacious surface molecule, EPGENGT procyclin represents the first repetitive surface protein in T. congolense thereby resembling the EP and GPEET procyclins from T. brucei. Our studies show that PRS is a surface marker for trypanosomes early during fly infection while EPGENGT procyclin is continuously expressed on parasites in the fly midgut.
EPG modification of eEF1A
We have also been interested in a rare and unusual protein modification that has been discovered in elongation factor 1A (eEF1A) and involves the covalent attachment of ethanolamine-phosphoglycerol (EPG) to two glutamic acids residues. Using T. brucei as a model organism, we studied the biosynthetic steps leading to this modification to investigate its possible biological function. Our results showed that the phospholipid phosphatidylethanolamine is the precursor of the EPG moiety of T. brucei eEF1A.