Screening of Protein Tyrosine Phosphatase 1B Inhibitors from Actinomycete Extracts Using Recombinant <i>Saccharomyces cerevisiae</i>

Protein tyrosine phosphatase 1B (PTP1B) removes phosphate groups from phosphorylated tyrosine proteins in human cells, particularly in the insulin and leptin signaling pathways. It is a key drug target for ailments such as type 2 diabetes and obesity. However, there is a lack of highly specific PTP1B inhibitor drugs. This study employed recombinant <i>Saccharomyces cerevisiae</i> that co-expressed PTP1B and v-Src (viral sarcoma protein tyrosine kinase) to screen for novel PTP1B inhibitors derived from actinomycete extracts. Eight extracts significantly suppressed the growth of the recombinant <i>S. cerevisiae</i> by inhibiting PTP1B expression, indicating their potential as PTP1B inhibitors. In a protein-chip assay, actinomycete extract 4585DW showed PTP1B inhibitory activity comparable to the positive controls, suramin and vanadate. The extract was non-cytotoxic in mammalian and yeast cells and inhibited PTP1B with <i>K</i>m and <i>V</i>max values of 10.91 ± 0.50 mM and 0.02 ± 0.00 μmol/min, respectively. In conclusion, 4585DW is a promising candidate for further investigation as a PTP1B inhibitor.