Post-translational modifications (PTMs), including phosphorylation and persulfidation, regulate the activity of SNF1-RELATED PROTEIN KINASE2.6 (SnRK2.6). Here, we report how persulfidations and phosphorylations of SnRK2.6 influence each other. The persulfidation of cysteine C131/C137 alters SnRK2.6 structure and brings the serine S175 residue closer to the aspartic acid D140 that acts as ATP-γ-phosphate proton acceptor, thereby improving the transfer efficiency of phosphate groups to S175 to enhance the phosphorylation level of S175. Interestingly, we predicted that S267 and C137 were predicted to lie in close proximity on the protein surface and found that the phosphorylation status of S267 positively regulates the persulfidation level at C137. Analyses of the responses of dephosphorylated and depersulfidated mutants to abscisic acid and the H₂S-donor NaHS during stomatal closure, water loss, gas exchange, Ca²⁺ influx, and drought stress revealed that S175/S267-associated phosphorylation and C131/137-associated persulfidation are essential for SnRK2.6 function in vivo. In light of these findings, we propose a mechanistic model in which certain phosphorylations facilitate persulfidation, thereby changing the structure of SnRK2.6 and increasing its activity.

翻译后修饰 (PTM)，包括磷酸化和过硫化，调节 SNF1 相关蛋白激酶 2.6 (SnRK2.6) 的活性。在这里，我们报告了 SnRK2.6 的过硫化和磷酸化如何相互影响。半胱氨酸 C131/C137 的过硫化改变了 SnRK2.6 结构，使丝氨酸 S175 残基更接近充当 ATP-γ-磷酸质子受体的天冬氨酸 D140，从而提高磷酸基团向 S175 的转移效率，从而提高磷酸化水平的 S175。有趣的是，我们预测 S267 和 C137 被预测为靠近蛋白质表面，并发现 S267 的磷酸化状态正向调节 C137 的过硫化水平。脱磷酸和脱硫突变体对脱落酸和H的反应分析^{气孔关闭、水分流失、气体交换、Ca 2+流入和干旱胁迫期间的}₂ S 供体 NaHS表明，S175/S267 相关的磷酸化和 C131/137 相关的过硫化对于体内SnRK2.6 功能至关重要。鉴于这些发现，我们提出了一种机制模型，其中某些磷酸化促进过硫化，从而改变 SnRK2.6 的结构并增加其活性。