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Reactive oxygen species‐mediated BIN 2 activity revealed by single‐molecule analysis
Author(s) -
Song Song,
Wang Haijiao,
Sun Mengyuan,
Tang Jie,
Zheng Binglian,
Wang Xuelu,
Tan YanWen
Publication year - 2019
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15669
Subject(s) - brassinosteroid , reactive oxygen species , chemistry , bin , phosphorylation , signal transduction , arabidopsis thaliana , biochemistry , cell signaling , cysteine , arabidopsis , microbiology and biotechnology , mutant , biophysics , biology , enzyme , gene , algorithm , computer science
Summary Much evidence has shown that reactive oxygen species ( ROS ) regulate several plant hormone signaling cascades, but little is known about the real‐time kinetics and the underlying molecular mechanisms of the target proteins in the brassinosteroid ( BR ) signaling pathway. In this study, we used single‐molecule techniques to investigate the true signaling timescales of the major BR signaling components BRI 1‐ EMS ‐ SUPPRESSOR 1 ( BES 1) and BRASSINOSTEROID INSENSITIVE 2 ( BIN 2) of Arabidopsis thaliana . The rate constants of BIN 2 associating with ATP and phosphorylating BES 1 were determined to be 0.7 ± 0.4 mM −1 s −1 and 2.3 ± 1.4 s −1 , respectively. Interestingly, we found that the interaction of BIN 2 and BES 1 was oxygen‐dependent, and oxygen can directly modify BIN 2. The activity of BIN 2 was switched on via modification of specific cysteine (Cys) residues, including C59, C95, C99 and C162. The mutation of these Cys residues inhibited the BR signaling outputs. These findings demonstrate the power of using single‐molecule techniques to study the dynamic interactions of signaling components, which is difficult to be discovered by conventional physiological and biochemical methods.