Sulfur depletion induces autophagy through Ecl1 family genes in fission yeast

Abstract

Autophagy comprises one of the intracellular degradation systems conserved from yeasts to humans. This system plays a vital role in the degradation of intracellular components such as proteins and organelles in the processes of their exclusion and turnover. Autophagy is also necessary for adaptation to environmental changes, including depletion of various nutrients. Till date, several autophagy-related genes and mechanisms have been identified, wherein the budding yeast Saccharomyces cerevisiae has significantly contributed to this identification (Mizushima et al., 2011; Ohsumi, 2014; Xie & Klionsky, 2007). Although autophagy is widely conserved, there exist some differences in the conditions that induce autophagy and its related factors among species. For instance, autophagy is induced by carbon depletion in S. cerevisiae, but not in Schizosaccharomyces pombe (Mukaiyama et al., 2009). Moreover, autophagy factors are partially different between these two species (Mukaiyama et al., 2010). Yeasts have also contributed to lifespan studies, and a chronological lifespan is defined as the survival period after entry into the stationary phase (Fabrizio & Longo, 2003). Earlier, the Ecl1 family genes (ecl1 + , ecl2 + and ecl3 + , respectively) were identified whose over-expression was found to cause the extension of the chronological lifespan in S. pombe (Ohtsuka et al., 2008, 2009). These genes encode small proteins consist of about 80 amino acids, respectively, but their molecular functions have been unclear. However, phenotypic analysis revealed that Ecl1 family genes are also essential for the appropriate cellular response to sulfur depletion (Ohtsuka et al., 2017). Sulfur is one of the essential nutrients and is present in sulfur compounds such as biotin, thiamine, coenzyme A, lipoic acid and sulfur amino acid. Sulfur depletion induces cellular responses such as lifespan extension, morphological changes, and cell cycle arrest in S. pombe, and these phenomena are almost completely dependent on the Ecl1 family genes (Ohtsuka et al., 2017).

Response to sulfur in Schizosaccharomyces pombe

“… 2017 ; Shimasaki et al . 2020 ). In autophagy-deficient cells, CLS extension was significantly reduced under sulfur starvation, so autophagy induction is considered to be one cause of CLS extension (Shimasaki et al .…”

“…In autophagy-deficient cells, CLS extension was significantly reduced under sulfur starvation, so autophagy induction is considered to be one cause of CLS extension (Shimasaki et al . 2020 ). In addition, under this condition, the levels of ribosomal factors also decrease in Ecl1 family gene-dependent manner (Ohtsuka et al 2017 , 2021 ).…”

3,3’-Diindolylmethane induces apoptosis and autophagy in fission yeast

“…5A). Nitrogen starvation [32,34], sulfur depletion [35], or ER stress [32] induce autophagy in fission yeast. It remains unclear how DIM induces autophagy in fission yeast.…”

3,3’-Diindolylmethane induces apoptosis and autophagy in fission yeast

“…Nitrogen starvation induces autophagy in fission yeasts, which generates a nitrogen source for adaptation [33,34]. Sulfur starvation also induces autophagy in fission yeasts [35]. Autophagy contributes to maintaining cellular viability in both nitrogen [25] and sulfur starvation [35].…”

“…Sulfur starvation also induces autophagy in fission yeasts [35]. Autophagy contributes to maintaining cellular viability in both nitrogen [25] and sulfur starvation [35]. Atg8 is critical for autophagosome formation in fission yeasts [8,26] and used as a general autophagy marker that is distributed in the cytoplasm but forms bright foci when autophagy is induced by nitrogen starvation [31,34,36].…”