8QTT

Crystal structure of a C-terminally truncated version of Arabidopsis thaliana 14-3-3 omega in complex with a phosphopeptide from the inhibitor protein BKI1.

8QTT の概要

• エントリーDOI: 10.2210/pdb8qtt/pdb
• 関連するPDBエントリー: 8QTF
• 分子名称: 14-3-3-like protein GF14 omega, BRI1 kinase inhibitor 1, FORMIC ACID, ... (5 entities in total)
• 機能のキーワード: 14-3-3, brassinosteroid signaling, phosphopeptide, transcription factor, signal transduction, protein binding, kinase inhibitor
• 由来する生物種: Arabidopsis thaliana (thale cress); 詳細
• タンパク質・核酸の鎖数: 20
• 化学式量合計: 279344.56

構造登録者

Hothorn, M.,Obergfell, E. (登録日: 2023-10-13, 公開日: 2023-11-15, 最終更新日: 2024-10-16)

主引用文献

Obergfell, E.,Hohmann, U.,Moretti, A.,Chen, H.,Hothorn, M.
Mechanistic insights into the function of 14-3-3 proteins as negative regulators of brassinosteroid signaling in Arabidopsis.
Plant Cell.Physiol., 2024

PubMed Abstract: Brassinosteroids (BRs) are vital plant steroid hormones sensed at the cell surface by a membrane signaling complex comprising the receptor kinase BRI1 and a SERK-family co-receptor kinase. Activation of this complex lead to dissociation of the inhibitor protein BKI1 from the receptor and to differential phosphorylation of BZR1/BES1 transcription factors by the glycogen synthase kinase 3 protein BIN2. Many phosphoproteins of the BR signaling pathway, including BRI1, SERKs, BKI1 and BZR1/BES1 can associate with 14-3-3 proteins. In this study, we use quantitative ligand binding assays to define the minimal 14-3-3 binding sites in the N-terminal lobe of the BRI1 kinase domain, in BKI1, and in BZR1 from Arabidopsis thaliana. All three motifs require to be phosphorylated to specifically bind 14-3-3s with mid- to low micromolar affinity. BR signaling components display minimal isoform preference within the 14-3-3 non-ε subgroup. 14-3-3λ and 14-3-3ω isoform complex crystal structures reveal that BKI1 and BZR1 bind as canonical type II 14-3-3 linear motifs. Disruption of key amino acids in the phosphopeptide binding site through mutation impairs the interaction of 14-3-3λ with all three linear motifs. Notably, quadruple loss-of-function mutants from the non-ε group exhibit gain-of-function brassinosteroid signaling phenotypes, suggesting a role for 14-3-3 proteins as overall negative regulators of the BR pathway. Collectively, our work provides further mechanistic and genetic evidence for the regulatory role of 14-3-3 proteins at various stages of the brassinosteroid signaling cascade.

PubMed: 38783418
DOI: 10.1093/pcp/pcae056

実験手法

X-RAY DIFFRACTION (2.35 Å)