Prolexys Pharmaceuticals has announced the publication of the first extensive description of the protein interaction network of the huntingtin (Htt) protein.
Huntington's Disease (HD) is a fatal neurodegenerative condition caused by a large stretch of amino acid glutamine (polyglutamine tract) in the huntingtin (Htt) protein.
The results, published in the April 2007 issue of PLoS Genetics, are the result of a collaborative effort. The Prolexys Project Leader for this study was Dr. Robert Hughes, now an assistant professor at the Buck Institute for Age Research in Novato, California.
Other collaborators included the scientists from the Baylor College of Medicine, Houston, and Fred Hutchinson Cancer Research Center in Seattle, Washington. These studies demonstrate that high-throughput screening for protein interactions combined with genetic validation provides an opportunity to understand the biological basis of the diseases associated with polyglutamine toxicity.
Protein-Protein interactions in normal and polyglutamine-Htt were elucidated by employing a high-throughput version of the yeast 2-hybrid assay (HyNet™) developed at Prolexys.
The second process, affinity pull-down followed by mass spectrometry (HySpec™), employed purified huntingtin protein as bait to identify proteins that bind specifically to either normal or polyglutamine form of huntingtin protein. This effort led to the identification of 234 high-confidence Htt-associated proteins, 104 of which were found with the yeast method (HyNet™) and 130 with the pull downs (HySpec™).
Of the 234 hits, 60 genes were tested in a Drosophila fruit fly model to determine if they had anything to do with Huntington's disease. Validation experiments in fruit fly resulted in the identification of 17 loss-of-function suppressors, or genes which upon knock down cause an improvement in the disease phenotype.
The 17 genes identified in this study therefore represent potential targets for therapeutic intervention in HD. "The results of this study demonstrate the power of using the protein interaction discovery technologies in conjunction with the functional validation experiments to understand the disease biology and to identify potential therapeutic intervention points," said Dr. Sudhir Sahasrabudhe, Chief Scientific Officer of Prolexys Pharmaceuticals.