Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, 41092 Seville, Spain.
Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas, 50059 Zaragoza, Spain.
Plant Cell. 2020 Dec;32(12):3902-3920. doi: 10.1105/tpc.20.00766. Epub 2020 Oct 9.
Hydrogen sulfide is a signaling molecule that regulates essential processes in plants, such as autophagy. In Arabidopsis (), hydrogen sulfide negatively regulates autophagy independently of reactive oxygen species via an unknown mechanism. Comparative and quantitative proteomic analysis was used to detect abscisic acid-triggered persulfidation that reveals a main role in the control of autophagy mediated by the autophagy-related (ATG) Cys protease AtATG4a. This protease undergoes specific persulfidation of Cys170 that is a part of the characteristic catalytic Cys-His-Asp triad of Cys proteases. Regulation of the ATG4 activity by persulfidation was tested in a heterologous assay using the CrATG8 protein as a substrate. Sulfide significantly and reversibly inactivates AtATG4a. The biological significance of the reversible inhibition of the ATG4 by sulfide is supported by the results obtained in Arabidopsis leaves under basal and autophagy-activating conditions. A significant increase in the overall ATG4 proteolytic activity in Arabidopsis was detected under nitrogen starvation and osmotic stress and can be inhibited by sulfide. Therefore, the data strongly suggest that the negative regulation of autophagy by sulfide is mediated by specific persulfidation of the ATG4 protease.
硫化氢是一种信号分子，调节植物中的基本过程，如自噬。在拟南芥中，硫化氢通过未知机制独立于活性氧负调控自噬。通过比较和定量蛋白质组学分析，检测到脱落酸触发的过硫化，这揭示了自噬相关（ATG）半胱氨酸蛋白酶 AtATG4a 介导的自噬控制的主要作用。这种蛋白酶经历 Cys170 的特异性过硫化，Cys170 是 Cys 蛋白酶特征性催化 Cys-His-Asp 三肽的一部分。使用 CrATG8 蛋白作为底物，在异源测定中测试了过硫化对 ATG4 活性的调节。硫化物显著且可逆地使 AtATG4a 失活。在基础和自噬激活条件下，在拟南芥叶片中获得的结果支持硫化物可逆抑制 ATG4 的生物学意义。在氮饥饿和渗透胁迫下，在拟南芥中检测到整体 ATG4 蛋白水解活性显著增加，并且可以被硫化物抑制。因此，数据强烈表明，硫化物对自噬的负调控是通过 ATG4 蛋白酶的特异性过硫化介导的。
