Unveiling a new regulator: Vacuolar V-ATPase mediates brassinosteroid signaling in Arabidopsis

Plant growth and development are intricately regulated by hormones such as auxin, gibberellins, jamonates, cytokinins, and brassinosteroids (BR). BRs are a group of plant steroid hormones that play a vital role in plant growth and response to the environment. BRs regulate many biological processes including cell elongation, cell division, and male fertility as well as abiotic and biotic stress responses. To facilitate modulation of these biological processes, induction of BR signaling results in massive alterations in the transcriptome, proteome, and phosphoproteome (Clark et al., 2021). BRs are perceived by the plasma membrane-bound leucine-rich repeat receptor BRASSINOSTEROID INSENSITIVE1 (BRI1), causing a conformational change in the receptor and promoting interaction with the co-receptor BRI1-ASSOCIATED KINASE1 (BAK1). BR perception initiates a downstream kinase signaling cascade inactivating the GSK3-like kinase BRASSINOSTEROID INSENSITIVE 2 (BIN2), which is a negative regulator of BR signaling, ultimately resulting in dephosphorylation and activation of BRASSINAZOLE RESISTANT 1 (BZR1) and BRI1-EMS-SUPPRESSOR1 (BES1) (Wang et al., 2016; Nolan et al., 2020; Wang et al., 2021).