The ATCG of drug discovery

The publication of human and microbial genomic sequences has resulted in the availability of large amounts of data that are directly relevant to the discovery of novel and useful drug targets. The elucidation of the function of new genes is not a simple matter and human genetic studies have been among the most useful in identifying genes implicated in disease, although homologs, or orthologs, of human genes in mouse, worm, fly and yeast genomes have also been useful in deciphering gene function. The advent of genomics has led into the study of protein structure and function under the rubric of proteomics. Proteins function in a cell mostly by interacting with other proteins, and protein interaction maps of cellular circuits are now available. Screening strategies to address protein-protein interactions are being developed, and many drug targets in the future are expected to be directed towards these interactions. In addition to using genetic and analytical approaches for finding new drug targets, chemical libraries can be used to inhibit the activity of new proteins, and thus reveal function. The combination of high-throughput screening with testing compounds for ADME (absorption, distribution, metabolism and excretion) and toxicity will help in the early clarification of clinical utility of both new drug targets, as well as drug candidates.