SAN RAMON, Calif., July 5 /PRNewswire/ -- Scientists at the University of Montreal have validated a technological breakthrough with the potential to revolutionize the understanding of gene function, the discovery of pathways controlling cell behavior, the identification of novel targets for drug discovery, and the elucidation of drug function within the complex biological setting of the living cell.
In an article entitled ``Visualization of Biochemical Networks in Living Cells'', published in the July 3 issue of PNAS ( pnas.org ), Drs. Ingrid Remy and Stephen W. Michnick utilized protein-fragment complementation assays (PCA) as a single strategy to directly map protein interactions within biochemical pathways; pinpoint the location of the interactions within living cells; identify novel interactions among proteins actively participating in signaling events and drug effects; and establish the precise sequence of molecular events leading from an external signal to a cellular response in key biochemical pathways.
Key findings of the publication are as follows:
*Combines genomics and systems biology. Using PCA, the authors introduced
genes directly into living cells and used cell survival or fluorescence
as a readout of protein-protein interactions, eliminating the need for
protein purification, complex instrumentation, or artificial systems
protein function studies.
*Any gene can be characterized with PCA. The technology was equally
sensitive and specific for genes encoding a wide variety of protein
sizes, subcellular locations, and biochemical functions, including
protein classes representing druggable targets such as kinases and
phosphatases.
*Novel interactions can be found. Using PCA, the authors identified five
novel protein interactions linked to key cellular pathways important in
insulin and growth factor responses, with implications for new
therapeutic strategies for cancer and diabetes.
*Dynamic responses of protein complexes can be detected. The authors
showed that the activation of proteins in real time in response to cell
signals, such as insulin, could be detected by an increase
fluorescence. Moreover, the precise sequence of events leading from
signal to cellular response could be elucidated by establishing a
pharmacological profile of the response to agents acting upstream and
downstream of the proteins of interest.
*The actual site of action of proteins within cells can be visualized.
Using a fluorescent probe, the site of action of each protein could
seen under a microscope. For example, proteins acting at the membrane of
the cell could be clearly distinguished from proteins acting within in
the cytosol of the cell.
*Drug effects on pathways can be determined in living cells. Using drugs
that act upon specific proteins, the authors were able to quantitate the
drug effects not only on the target itself but also on proteins
downstream of the drug. The potential of PCA to detect the complete
spectrum of biological functions of drugs enables the biological
characterization of small molecules and will facilitate a genome-wide
search for small molecules with novel mechanisms of action.
Proteins, which are encoded by genes, are the molecular targets for the vast majority of drugs on the market today. The recent completion of the sequence of the human genome raises the hope that a large number of novel drug targets can be identified and validated. Validation of novel proteins as drug targets demands a comprehensive understanding of protein function in the biological context of a living cell, tissue or animal. The availability of rapid, automatable approaches to characterizing protein function in the context of biology is vital to deciphering the functions of the thousands of proteins encoded by the genome. The characteristics of PCA make it ideal for the elucidation of the true biological function of large numbers of proteins on a genome-wide scale.
PCA, which was invented by Dr. Stephen Michnick, is being commercialized exclusively by Odyssey Pharmaceuticals, Inc. of San Ramon, California. Odyssey is a privately held biotechnology company that is utilizing PCA as a high-throughput target validation and drug discovery platform. The company's mission is to become a leading pharmaceutical company by identifying and validating large numbers of pharmaceutical targets arising from the human genome, enabling the development of drugs for a variety of human diseases. Visit Odyssey on the web at www.odysseypharma.com . |
