Applications and Practical Examples

The antifungal natural product TSA, originally isolated from a Streptomyces, was found to have reversible biological activity at low nanomolar concentrations. Yoshida and coworkers [4] demonstrated that TSA causes the induction of Friend leukemia cell differentiation as well as inhibition of the cell cycle of normal rat fibroblasts in the Gi and G2 phases. This initial work revealed that at low nanomolar concentrations, TSA induces the accumulation of acetylated histones because of inhibiting HD AC activity within the cell. 

TSA has also been shown to induce apoptosis in various tumor cell lines 

The irreversible HDAC inhibitor TPX was first isolated as a fungal metabolite that induced morphological reversion of v-sis-transformed NIH 3T3 cells [10]. Using the known structure-activity relationship between other HDAC inhibitors as a guide, a TPX affinity reagent was synthesized and used to identify its target protein as a HDAC [11]. 

TPX was used to elucidate the protein interactions necessary for HDAC mediated transcriptional repression via the Mad Max ternary complex [12], Previous studies had suggested that Mad Max transcriptional repression was mediated by ternary complex formation with another unknown protein. Biochemical experiments identified the proteins mSin3A or B as the primary candidates responsible for this negative transcriptional function. Coexpression of activated or inactivated MAD (a DNA-binding transcription factor) in the presence of TPX demonstrated that HDAC activity was necessary for ternary complex formation. Additionally, these and other experiments showed that the Mad Max heterocomplexes repress transcription in a mSin3A-associated HD AC-dependent manner. 

Like TPX, the microbially derived HDAC inhibitor depudecin 4 was also isolated based on its ability to reverse the transformed cellular phenotype of tumor cells. This diepoxide-containing natural product induced a flat phenotype in Kj-ras-transformed NIH 3T3 cells and was further characterized as an HDAC inhibitor by its ability to induce the accumulation of acetylated histones [13]. Apicidin (APC) 3, a cyclic tetrapeptide HDAC inhibitor with 

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Applications and Practical Examples 8.2.3.1 Labeling of AGT Fusion Proteins... 

Applications and Practical Examples 15.4.4.1 Biological Expression of GPCRs... 

Applications and Practical Examples 336 Example 1 Mitosis and Spindle Assembly 336 Example 2 Protein Acetylation 338 Example 3 Chemical-genomic Profiling 340 Future Development 344 Conclusion 347 Acknowledgments 348 References 349... 

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