Post-Golgi Sec Proteins Are Required for Autophagy in Saccharomyces cerevisiae

被引:140
作者
Geng, Jiefei
Nair, Usha
Yasumura-Yorimitsu, Kyoko
Klionsky, Daniel J. [1 ]
机构
[1] Univ Michigan, Inst Life Sci, Ann Arbor, MI 48109 USA
基金
美国国家卫生研究院;
关键词
NUCLEOTIDE EXCHANGE FACTOR; SECRETORY PATHWAY; SELECTIVE AUTOPHAGY; VESICULAR TRANSPORT; VESICLE FORMATION; AMINOPEPTIDASE-I; YEAST; CYTOPLASM; PHAGOPHORE; MACHINERY;
D O I
10.1091/mbc.E09-11-0969
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
In eukaryotic cells, autophagy mediates the degradation of cytosolic contents in response to environmental change. Genetic analyses in fungi have identified over 30 autophagy-related (ATG) genes and provide substantial insight into the molecular mechanism of this process. However, one essential issue that has not been resolved is the origin of the lipids that form the autophagosome, the sequestering vesicle that is critical for autophagy. Here, we report that two post-Golgi proteins, Sec2 and Sec4, are required for autophagy. Sec4 is a Rab family GTPase, and Sec2 is its guanine nucleotide exchange factor. In sec2 and sec4 conditional mutant yeast, the anterograde movement of Atg9, a proposed membrane carrier, is impaired during starvation conditions. Similarly, in the sec2 mutant, Atg8 is inefficiently recruited to the phagophore assembly site, which is involved in autophagosome biogenesis, resulting in the generation of fewer autophagosomes. We propose that following autophagy induction the function of Sec2 and Sec4 are diverted to direct membrane flow to autophagosome formation.
引用
收藏
页码:2257 / 2269
页数:13
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