The leucine-rich repeat receptor kinase BIR2 is a negative regulator of BAK1 in plant immunity
Authors: Sacco C de Vries
Julia Imkampe
Frans Tax
Sandra Postel
Xiaofeng Wang
Christoph Bücherl
Steven Clouse
Birgit Kemmerling
Michael Wierzba
Thorsten Nürnberger
Sjef Boeren
Christian Kiefer
Thierry Halter
Sara Mazzotta
Jan Willem Borst
Mark Stahl
Delphine Chinchilla
Cyril Zipfel
Journal: Current Biology (2014)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: LRR receptors; BAK1; RLKs; brassinosteroid; innate immunity
Affiliations: Department of Plant Biochemistry (ZMBP), Eberhard Karls University Tübingen, 72076 Tübingen, Germany., Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA., Department of Plant Biochemistry (ZMBP), Eberhard Karls University Tübingen, 72076 Tübingen, Germany; The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK., Analytics (ZMBP), Eberhard Karls University Tübingen, 72076 Tübingen, Germany., Zurich-Basel Plant Science Center, Department of Environmental Sciences, University of Basel, 4056 Basel, Switzerland., Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695-7609, USA., The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK., Laboratory of Biochemistry, Wageningen University, Wageningen 6703 HA, the Netherlands., Department of Plant Biochemistry (ZMBP), Eberhard Karls University Tübingen, 72076 Tübingen, Germany. Electronic address: .

Abstract:  Background: Transmembrane leucine-rich repeat (LRR) receptors are commonly used innate immune receptors in plants and animals but can also sense endogenous signals to regulate development. BAK1 is a plant LRR-receptor-like kinase (RLK) that interacts with several ligand-binding LRR-RLKs to positively regulate their functions. BAK1 is involved in brassinosteroid-dependent growth and development, innate immunity, and cell-death control by interacting with the brassinosteroid receptor BRI1, immune receptors, such as FLS2 and EFR, and the small receptor kinase BIR1, respectively. Results: Identification of in vivo BAK1 complex partners by LC/ESI-MS/MS uncovered two novel BAK1-interacting RLKs, BIR2 and BIR3. Phosphorylation studies revealed that BIR2 is unidirectionally phosphorylated by BAK1 and that the interaction between BAK1 and BIR2 is kinase-activity dependent. Functional analyses of bir2 mutants show differential impact on BAK1-regulated processes, such as hyperresponsiveness to pathogen-associated molecular patterns (PAMP), enhanced cell death, and resistance to bacterial pathogens, but have no effect on brassinosteroid-regulated growth. BIR2 interacts constitutively with BAK1, thereby preventing interaction with the ligand-binding LRR-RLK FLS2. PAMP perception leads to BIR2 release from the BAK1 complex and enables the recruitment of BAK1 into the FLS2 complex. Conclusions: Our results provide evidence for a new regulatory mechanism for innate immune receptors with BIR2 acting as a negative regulator of PAMP-triggered immunity by limiting BAK1-receptor complex formation in the absence of ligands. 

Retracted: No

PubPeer comments:
 *[right]* Figure 8.  Transwell assay showing the effect of Evodiamine on the invasion of the SW480 cells. Evodiamine led to inhibition of cell invasion in SW480 cancer cells. *[left]* Fig. 3 from [Chen et al (2017)] .  Effect of plumbagin on the invasion capacity of glioma cells in vitro. (A): The cells were treated with vehicle or plumbagin (1.0 and 2.0 u03bcM) for 24 h, and cell invasion was then tested by Matrigel-coated transwell system. Invasion cells on the bottom side of the membrane were fixed and stained with haematoxylin and eosin solution. ![] , 
 The paper has undergone a stealth revision or correction, replacing Figure 8. Figures 3 and 5 were presumably also bogus as they were replaced at the same time. The version of the paper currently provided on the journal website was created modified on 19January 2021. ![file] Interested readers can still consult the original version via a copy [archived at ResearchGate] . That version was created on 17 January **2010** according to PDF metadata; perhaps the date on the computer had been incorrectly set. ![file] ![file] , 
 Presumably the authors and editors are satisfied with the authenticity of Fig 2, having passed by the opportunity to replace it. ![file] Can they comment on the peculiar features revealed by increasing lightness, such as the sharp notch in the lower-left cell of the 20-micro-M panel (marked here with an arrow)? Or what appear to be erasures? , 
 #3 It appears that Fig 2 was bogus after all, and in the third version of this paper (dated 8 February 2021), it has been replaced. ![file] ,