Yoshioka Michiru, Yamada Keiichi, Yamaguchi Yoshihiro, Ogita Akira, Fujita Ken-Ichi, Tanaka Toshio
Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
Department of Chemistry and Chemical Biology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
Microbiology (Reading). 2016 May;162(5):848-854. doi: 10.1099/mic.0.000269. Epub 2016 Mar 3.
In this study, we demonstrated that in distilled water, a nutrient-starved condition that elicits autophagy in Saccharomyces cerevisiae, an array of autophagy-deficient mutants are resistant to the fungicidal effects of amphotericin B. In addition, we found that a dansyl-labelled derivative of the antibiotic colocalized with disintegrated vacuoles throughout the cytoplasm in the amphotericin B-sensitive parental strain suspended in distilled water. In contrast, the dansyl-labelled derivative was not internalized in the Δatg18 strain, which is deficient in the formation of autophagosomes, a key early step in autophagy. However, the derivative accumulated without significant toxicity in structurally intact vacuoles in the Δvma1 mutant, which is deficient in the degradation of autophagic bodies, the final stage in autophagy. Our data support the idea that amphotericin B can utilize autophagy-dependent trafficking into the intra-vacuolar lumen, where it interacts with the luminal leaf of the membrane to cause structurally catastrophic effects.
在本研究中，我们证明，在蒸馏水中，一种能在酿酒酵母中引发自噬的营养饥饿条件下，一系列自噬缺陷型突变体对两性霉素B的杀菌作用具有抗性。此外，我们发现，在悬浮于蒸馏水中的两性霉素B敏感亲本菌株中，抗生素的丹磺酰标记衍生物与整个细胞质中解体的液泡共定位。相比之下，丹磺酰标记衍生物在自噬体形成缺陷的Δatg18菌株中未被内化，自噬体形成是自噬的关键早期步骤。然而，该衍生物在Δvma1突变体结构完整的液泡中积累且无明显毒性，Δvma1突变体在自噬体降解（自噬的最后阶段）方面存在缺陷。我们的数据支持这样一种观点，即两性霉素B可利用依赖自噬的转运进入液泡内腔，在那里它与膜的腔内叶相互作用，从而产生结构上的灾难性影响。
