自噬是将细胞组分包裹进具有双层膜结构的自噬体并运送至液泡/溶酶体降解的过程。已有研究认为酿酒酵母I型酪蛋白激酶家族成员Hrr25参与选择性自噬，但不影响饥饿诱导的巨自噬（macroautophagy）。由于Hrr25在W303以外绝大部分菌株中是必需基因，上述研究采用了条件性敲低方法，我们前期研究表明残存的少量Hrr25可能影响研究结论，有必要利用敲除突变体深入研究其在巨自噬中的功能。前期数据利用敲除Hrr25的W303菌株和温度敏感型突变体多角度证明了Hrr25在巨自噬中的重要作用。本课题拟深入研究Hrr25在巨自噬上的作用位点，阐明其与自噬相关蛋白Atg复合物的相互作用，解析招募Hrr25的上游因子，并鉴定其在巨自噬通路上的底物蛋白。系统解析Hrr25调控巨自噬的分子机制，有助于准确认识Hrr25与自噬的关系，揭示其影响巨自噬的新功能、新底物、新模式，为深入了解巨自噬调控网络提供新信息

The induction of autophagy by nutrient deprivation leads to a rapid increase in the formation of autophagosomes, double-membrane vesicles that sequester cytoplasmic materials and transport them to lysosome/vacuole for degradation. The serine/threonine kinase Hrr25, a casein kinase 1 (CK1) family member in Saccharomyces cerevisiae, has been reported to regulate selective autophagy but not non-selective macroautophagy. An auxin-inducible degron strain was used in previous report because Hrr25 is essential for growth in most strain backgrounds except W303. Our preliminary data in hrr25 deletion strain and temperature-sensitive strain showed Hrr25 is required for macroautophagy and that a defect in macroautophagy was not observed in the auxin-inducible degron strain because Hrr25 was not sufficiently depleted. To address the role of Hrr25 in macroautophagy, we propose to check which steps on macroautophagy pathway is affected in hrr25 mutants and test if Hrr25 interacts with Atg complex to regulate macroautophagy. We will also identify upstream proteins recruiting Hrr25 to macroautophagy pathway and the substrate of Hrr25 in macroautophagy. Our project will develop a further understanding of the role of casein kinase 1 member Hrr25 and provide new insights into how macroautophagy is precisely regulated in response to environmental cues.