Yvh1 protein phosphatase is required for pre-autophagosomal structure formation after TORC1 inactivation

The pre-autophagosomal structure (PAS) is a putative site for autophagosome formation in budding yeast. Upon nutrient depletion or rapamycin treatment, target of rapamycin complex 1 (TORC1) becomes inactive, inducing PAS formation and autophagy. Here, we show that Yvh1 phosphatase is critical for PAS formation, but not autophagy induction, after TORC1 inactivation.

Elucidation of novel budding yeast separase mutants

The mitotic separase cleaves Scc1 in cohesin to allow sister chromatids to separate from each other upon anaphase onset. Separase is also required for DNA damage repair. Here, we isolated and characterized 10 temperature-sensitive (ts) mutants of separase ESP1 in the budding yeast Saccharomyces cerevisiae. All mutants were defective in sister chromatid separation at the restricted temperature. Some esp1-ts mutants were hypersensitive to the microtubule poison benomyl and/or the DNA-damaging agent bleomycin. Overexpression of securin alleviated the growth defect in some esp1-ts mutants, whereas it rather exacerbated it in others. The Drosophila Pumilio homolog MPT5 was isolated as a high-dosage suppressor of esp1-ts cells. We discuss various features of separase based on these findings.