School of Biological Sciences, Seoul National University, Seoul, Republic of Korea.
Institute of Microbiology, Seoul National University, Seoul, Republic of Korea.
Autophagy. 2021 Apr;17(4):1013-1027. doi: 10.1080/15548627.2020.1746592. Epub 2020 Apr 2.
Macroautophagy/autophagy is an important catabolic process for maintaining cellular homeostasis by adapting to various stress conditions. Autophagy is mediated by a double-membrane autophagosome, which sequesters a portion of cytoplasmic components for delivery to the vacuole. Several autophagy-related () genes play crucial roles in autophagosome formation. The induction of genes must be tightly regulated to maintain a proper autophagic activity, but their regulatory mechanisms are still largely unknown. Here, we report that the trehalose-6-phosphate phosphatase Tps2 functions as a positive regulator of autophagy in . Cellular trehalose levels do not affect autophagy regulation by Tps2. Loss of Tps2 leads to impaired autophagic flux and reduced expre/ssion under nitrogen starvation. In Δ cells, Ume6 is predominantly dephosphorylated and represses transcription by binding to its promoter region. Tps2 regulates nuclear translocation and activation of Rim15 kinase, a negative regulator of Ume6, by causing the dissociation of Rim15 from the 14-3-3 proteins Bmh1/2 under nitrogen starvation, suggesting that Rim15 mediates the function of Tps2 as a positive regulator of induction. Furthermore, Tps2 plays a crucial role in the dephosphorylation of Ser1061 and Thr1075 residues of Rim15, which is important for controlling the dissociation of Rim15 from Bmh1/2 under nitrogen starvation. Together, our results reveal the role of Tps2 as a positive regulator of autophagy and provide new insight into the regulatory mechanisms of gene expression. ATG: autophagy-related; ChIP: chromatin immunoprecipitation; Co-IP: co-immunoprecipitation; DAPI: 4',6-diamidino-2-phenylindole; GFP: green fluorescent protein; PKA: protein kinase A; PtdIns3K: phosphatidylinositol 3-kinase; Rim15KI: kinase-inactive Rim15; Rim15-2A: Rim15; TEM: transmission electron microscopy; TORC1: target of rapamycin complex 1.
自噬是一种重要的分解代谢过程,通过适应各种应激条件来维持细胞内稳态。自噬是由双层自噬体介导的,它将细胞质的一部分隔离起来,用于输送到液泡中。几种自噬相关(ATG)基因在自噬体形成中起着关键作用。基因的诱导必须受到严格的调控,以维持适当的自噬活性,但它们的调控机制在很大程度上仍然未知。在这里,我们报告说海藻糖-6-磷酸磷酸酶 Tps2 在中作为自噬的正调控因子发挥作用。细胞海藻糖水平不会影响 Tps2 对自噬的调节。Tps2 的缺失导致氮饥饿下自噬通量受损和减少。在Δ细胞中,Ume6 主要去磷酸化,并通过结合其启动子区域抑制转录。Tps2 通过引起 Rim15 从氮饥饿下的 14-3-3 蛋白 Bmh1/2 中解离,调节核转位和 Rim15 激酶的激活,Rim15 激酶是 Ume6 的负调节剂,表明 Rim15 介导了 Tps2 作为诱导的正调节剂的功能。此外,Tps2 在 Rim15 的 Ser1061 和 Thr1075 残基的去磷酸化中起关键作用,这对于控制氮饥饿下 Rim15 从 Bmh1/2 中的解离很重要。总之,我们的结果揭示了 Tps2 作为自噬正调节剂的作用,并为研究提供了新的见解诱导基因表达的调控机制。ATG:自噬相关;ChIP:染色质免疫沉淀;Co-IP:免疫共沉淀;DAPI:4',6-二脒基-2-苯基吲哚;GFP:绿色荧光蛋白;PKA:蛋白激酶 A;PtdIns3K:磷脂酰肌醇 3-激酶;Rim15KI:激酶失活的 Rim15;Rim15-2A:Rim15;TEM:透射电子显微镜;TORC1:雷帕霉素靶蛋白复合物 1。