Small-molecule target identification

Gray, P.G. Schultz, F. Supek, A genome-wide overexpression screen in yeast for small-molecule target identification, Chem. Biol. 2005, 12, 55-63. 

Small-molecule target identification techniques are a hypothesis generating endeavor, requiring follow-up experimental verification. Once the potential targets are identified, the effort has just begun and the modulation of the protein must be corroborated - or ruled out - by methods orthogonal to the one used... 

Table 4.2 Summary chart of small-molecule target identification techniques [44].

Henthorn DC, Jaxa-Chamiec AA, Meldmm E. A GAL4-based yeast three-hybrid system for the identification of small molecule-target protein interactions. Biochem. Pharmacol. 2002 63 1619-1628. 

This book offers you the contemporary knowledge and techniques necessary to understand the entire research field of chemical biology. New technologies to dissect the interactions between small molecules and proteins are introduced with some examples of the identification of binding proteins of small molecules. The final chapter will be useful to get a bird s-eye view of recent progress on small molecules targeting proteins. 

Identification and Validation of Potential Small-Molecule Targets... 

Despite the complexity of the experiments and the enormous data manipulation necessary, complex biological pathways, as well as new drug targets are being identified by this method. Examples include screens for compounds that arrest cells in mitosis, that block cell migration, and that block the secretory pathway [50], or assays with primary T cells from PLP TCR transgenic mice for their inhibitory activity on the proliferation and secretion of proinflammatory cytokines in PLP-reactive T cells [51], and identification of small-molecule inhibitors of histone acetyltransferase activity [52]. 

In eukaryotes, translation initiation is rate-limiting with much regulation exerted at the ribosome recruitment and ternary complex (elF2 GTP Met-tRNAjMet) formation steps. Although small molecule inhibitors have been extremely useful for chemically dissecting translation, there is a dearth of compounds available to study the initiation phase in vitro and in vivo. In this chapter, we describe reverse and forward chemical genetic screens developed to identify new inhibitors of translation. The ability to manipulate cell extracts biochemically, and to compare the activity of small molecules on translation of mRNA templates that differ in their factor requirements for ribosome recruitment, facilitates identification of the relevant target. 

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