Cysteine thiol sulfinic acid in plant stress signaling
Jingjing Huang, Lindsy De Veirman, Frank Van Breusegem
Abstract
Abstract Cysteine thiols are susceptible to various oxidative posttranslational modifications (PTMs) due to their high chemical reactivity. Thiol‐based PTMs play a crucial role in regulating protein functions and are key contributors to cellular redox signaling. Although reversible thiol‐based PTMs, such as disulfide bond formation, S ‐nitrosylation, and S ‐glutathionylation, have been extensively studied for their roles in redox regulation, thiol sulfinic acid (–SO 2 H) modification is often perceived as irreversible and of marginal significance in redox signaling. Here, we revisit this narrow perspective and shed light on the redox regulatory roles of –SO 2 H in plant stress signaling. We provide an overview of protein sulfinylation in plants, delving into the roles of hydrogen peroxide‐mediated and plant cysteine oxidase‐catalyzed formation of –SO 2 H, highlighting the involvement of –SO 2 H in specific regulatory signaling pathways. Additionally, we compile the existing knowledge of the –SO 2 H reducing enzyme, sulfiredoxin, offering insights into its molecular mechanisms and biological relevance. We further summarize current proteomic techniques for detecting –SO 2 H and furnish a list of experimentally validated cysteine –SO 2 H sites across various species, discussing their functional consequences. This review aims to spark new insights and discussions that lead to further investigations into the functional significance of protein –SO 2 H‐based redox signaling in plants.