GPI Membrane Anchor Formation

~~~In eukaryotes, the C-terminus of some proteins are post-translationally modified to contain a complex glycosylphosphatidyl inositol (GPI) membrane anchor. The attachment of this anchor is mediated by the enzyme GPI transamidase (GPI-T). The result of the modification is that the target protein is "anchored" to the lipid bilayer and transported to the plasma membrane of the cell wall.

xxxGPI-T has been extensively characterized in vivo, but efforts to study and manipulate this enzyme in vitro have been limited by the lack of a soluble, quantitative kinetic assay for GPI-T transamidation and by the complexity of this membrane-bound, multi-subunit enzyme. Our lab is currently developing just such an assay using the principles of Fluorescence Resonance Energy Transfer (FRET).

Our interests in this project include:
• To develop a reliable, high-throughput in vitro assay for GPI-T
• To optimally purify quantities of GPI-T
• To probe the substrate propensities of GPI-T with chemically synthesized peptides and anchor analogs
• To develop unnatural GPI anchor analogs for the construction of novel protein biomaterials

We are grateful to Turner Biosystems for awarding a TBS-380 fluorometer to our lab as part of their Fluorometer grant program. Please visit Fluorometer-Grants.org to learn more about this program.