The transbilayer flip-flop of early intermediates in the glycosylphosphatidylinositol (GPI) biosynthetic pathway has been demonstrated using novel fluorescent GPI probes and a biochemical reconstitution approach.

Since their discovery (Low and Saltiel, 1988), glycosylphosphatidylinositol-anchored proteins (GPI-APs) have provoked intense interest as crucial regulators for growth, morphogenesis, reproduction, and disease pathogenesis in organisms ranging from yeast and trypanosomes to animals and plants. The lipid moiety, the glycosylphosphatidylinositol (GPI) anchor, is synthesized in the endoplasmic ret...

Covalent modification of proteins with phosphatidylinositol (PI) was first suggested as a novel mechanism of membrane attachment when it was found that PI-specific phospholipase C (PI-PLC) could release alkaline phosphatase from tissue slices [1-5]. Subsequent compositional analysis of Trypanosoma brucei variant surface glycoprotein (VSG) [6,7], Torpedo acetylcholinesterase [8], erythrocyte ace...

The expression of the vast majority of protein coding genes in trypanosomes is regulated exclusively at the post-transcriptional level. Developmentally regulated mRNAs that vary in levels of expression have provided an insight into one mechanism of regulation; a decrease in abundance is due to a shortened mRNA half-life. The decrease in half-life involves cis-acting elements in the 3' untransla...