Glucose Starvation Induced Autophagy in Saccharomyces cerevisiae: Inducing Conditions and Unique Involvement of Select Atg Proteins

Abstract: Nutrient depletion induces autophagy， a protective subcellular degradation process. We hypothesized that autophagy triggered by different conditions might involve diverse molecular mechanisms. Here we explored glucose starvation conditions that efficiently induce autophagy in budding yeast Saccharomyces cerevisiae， and examined the differential involvement of known Atg proteins in autophagy between nitrogen and glucose starvation conditions. We tested four conditions of glucose depletion， including YCD-D， SC-D， SD-D and YPD-D， and found SC-D to be most effective at inducing autophagy. We further tested the levels of autophagy in all 38 atg mutants under both glucose starvation (SC-D) and nitrogen starvation (SD-N) conditions， using the Pho8Δ60 assay and the GFP-Atg8 processing assay. We found that five mutants， including atg11Δ， atg20Δ， atg21Δ， atg23Δ and atg38Δ， displayed differing levels of autophagy under the two conditions. In particularly， autophagy in atg11Δ and atg20Δ cells was reduced in SC-D， but normal in SD-N; autophagy in atg21Δ and atg23Δ cells was blocked in SC-D， but only partially reduced in SD-N. In contrast， the level of autophagy in atg38Δ cells was normal in SC-D， but reduced in SD-N. Our work laid the foundation for further mechanistic investigation of glucose starvation induced autophagy.

CSTR: 32200.14.cjcb.2015.06.0011