Etp1 confers arsenite resistance by affecting ACR3 expression.

In a high-throughput yeast two-hybrid screen of predicted coiled-coil motif interactions in the Saccharomyces cerevisiae proteome, the protein Etp1 was found to interact with the yeast AP-1-like transcription factors Yap8, Yap1 and Yap6. Yap8 plays a crucial role during arsenic stress since it regulates expression of the resistance genes ACR2 and ACR3. The function of Etp1 is not well understood but the protein has been implicated in transcription and protein turnover during ethanol stress, and the etp1∆ mutant is sensitive to ethanol. In this current study, we investigated whether Etp1 is implicated in Yap8-dependent functions. We show that Etp1 is required for optimal growth in the presence of trivalent arsenite and for optimal expression of the arsenite export protein encoded by ACR3. Since Yap8 is the only known transcription factor that regulates ACR3 expression, we investigated whether Etp1 regulates Yap8. Yap8 ubiquitination, stability, nuclear localization and ACR3 promoter association were unaffected in etp1∆ cells, indicating that Etp1 affects ACR3 expression independently of Yap8. Thus, Etp1 impacts gene expression under arsenic and other stress conditions but the mechanistic details remain to be elucidated.

In vivo and in vitro anti-angiogenesis effect of venom-derived peptides (ICD-85).

BACKGROUND: Agiogenesis is the development of new blood vessels from pre-existing vasculatures. Although essential in the physiological process, it becomes pathological in various diseases including cancer. Preventing the formation of new blood vessels causes reductions in tumor size and metastasis. This study has been undertaken to elucidate the anti-angiogenesis effects of ICD-85 (derived peptides from venom). METHODS: We evaluated the ICD-85 anti-angiogenesis activity by the in vivo CAM assay and in vitro tube formation assay of human umbilical vein endothelial cells (HUVECs). The anti-proliferative activity of ICD-85 was also determined through MTT assay on HUVECs. RESULTS: Results of this study revealed the anti-proliferative activity of ICD-85 on the HUVEC cell line with an IC50 of 12 µg/mL. The in vivo CAM assay also clearly showed the prevention of new vascular formation when the chick embryos were exposed to 0.15 µg/disc of ICD-85. In vitro tube formation assay of HUVECs also showed the complete prevention of capillary tube formation on 18 µg/mL. CONCLUSION: Based on the results obtained in this study, ICD-85 has anti-angiogenesis activity as shown by the prevention of capillary tube formation and the CAM assay.