Specific threonine phosphorylation of a host target by two unrelated type III effectors activates a host innate immune receptor in plants

Eui Hwan Chung, Luis Da Cunha, Ai Jiuan Wu, Zhiyong Gao, Karen Cherkis, Ahmed J. Afzal, David MacKey, Jeffery L. Dangl

Research output: Contribution to journalArticlepeer-review

151 Citations (Scopus)


The Arabidopsis NB-LRR immune receptor RPM1 recognizes the Pseudomonas syringae type III effectors AvrB or AvrRpm1 to mount an immune response. Although neither effector is itself a kinase, AvrRpm1 and AvrB are known to target Arabidopsis RIN4, a negative regulator of basal plant defense, for phosphorylation. We show that RIN4 phosphorylation activates RPM1. RIN4 142-176 is necessary and, with appropriate localization sequences, sufficient to support effector-triggered RPM1 activation, with the threonine residue at position 166 being critical. Phosphomimic substitutions at T166 cause effector-independent RPM1 activation. RIN4 T166 is phosphorylated in vivo in the presence of AvrB or AvrRpm1. RIN4 mutants that lose interaction with AvrB cannot be coimmunoprecipitated with RPM1. This defines a common interaction platform required for RPM1 activation by phosphorylated RIN4 in response to pathogenic effectors. Conservation of an analogous threonine across all RIN4-like proteins suggests a key function for this residue beyond the regulation of RPM1.

Original languageEnglish
Pages (from-to)125-136
Number of pages12
JournalCell Host and Microbe
Issue number2
Publication statusPublished - 2011 Feb 17
Externally publishedYes

Bibliographical note

Funding Information:
We thank Sarah Grant for critical reading and members of the Dangl/Grant lab for helpful discussions. This work was funded by NSF Arabidopsis 2010 Program IOS-0929410 and DOE DE-FG05-95ER20187 grants to J.L.D. and by NSF grant MCB-0718882 and the Ohio Agricultural Research and Development Center of The Ohio State University to D.M. L.d.C. was supported by a graduate fellowship from the Plant Molecular Biology and Biotechnology program at The Ohio State University. K.C. is supported by an NIH Training Grant.

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Virology


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