6FG8 image
Entry Detail
PDB ID:
6FG8
Keywords:
Title:
Crystal structure of the BIR3 - SERK1 complex from Arabidopsis thaliana.
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2018-01-10
Release Date:
2018-01-24
Method Details:
Experimental Method:
Resolution:
1.25 Å
R-Value Free:
0.18
R-Value Work:
0.15
R-Value Observed:
0.15
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Somatic embryogenesis receptor kinase 1
Chain IDs:A
Chain Length:265
Number of Molecules:1
Biological Source:Arabidopsis thaliana
Polymer Type:polypeptide(L)
Description:Probable inactive receptor kinase At1g27190
Chain IDs:B
Chain Length:241
Number of Molecules:1
Biological Source:Arabidopsis thaliana
Primary Citation
The SERK3 elongated allele defines a role for BIR ectodomains in brassinosteroid signalling.
Nat Plants 4 345 351 (2018)
PMID: 29735985 DOI: 10.1038/s41477-018-0150-9

Abstact

The leucine-rich repeat receptor kinase (LRR-RK) BRASSINOSTEROID INSENSITIVE 1 (BRI1) requires a shape-complementary SOMATIC EMBRYOGENESIS RECEPTOR KINASE (SERK) co-receptor for brassinosteroid sensing and receptor activation1. Interface mutations that weaken the interaction between receptor and co-receptor in vitro reduce brassinosteroid signalling responses2. The SERK3 elongated (elg) allele3-5 maps to the complex interface and shows enhanced brassinosteroid signalling, but surprisingly no tighter binding to the BRI1 ectodomain in vitro. Here, we report that rather than promoting the interaction with BRI1, the elg mutation disrupts the ability of the co-receptor to interact with the ectodomains of BRI1-ASSOCIATED-KINASE1 INTERACTING KINASE (BIR) receptor pseudokinases, negative regulators of LRR-RK signalling6. A conserved lateral surface patch in BIR LRR domains is required for targeting SERK co-receptors and the elg allele maps to the core of the complex interface in a 1.25 Å BIR3-SERK1 structure. Collectively, our structural, quantitative biochemical and genetic analyses suggest that brassinosteroid signalling complex formation is negatively regulated by BIR receptor ectodomains.

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