Type III effector activation via nucleotide binding, phosphorylation, and host target interaction
2007

How a Bacterial Protein Activates Plant Immunity

publication 10 minutes Evidence: high

Author Information

Author(s): Darrell Desveaux, Alex U. Singer, Ai-Jiuan Wu, Brian C. McNulty, Laura Musselwhite, Zachary Nimchuk, John Sondek, Jeffery L. Dangl

Primary Institution: University of North Carolina at Chapel Hill

Hypothesis

How does the type III effector protein AvrB activate the plant immune system?

Conclusion

AvrB is activated inside the host cell by nucleotide binding and subsequent phosphorylation, and it interacts with the RIN4 protein to initiate plant immune responses.

Supporting Evidence

  • The structure of AvrB complexed with RIN4 was determined at 2.3 Å resolution.
  • AvrB residues important for RIN4 interaction are required for full RPM1 activation.
  • Phosphorylation of AvrB occurs in the presence of an unknown Arabidopsis protein.
  • Binding of ADP to AvrB is critical for its function in activating plant immunity.
  • Mutations in AvrB that disrupt RIN4 binding significantly reduce its ability to trigger immune responses.

Takeaway

A bacterial protein called AvrB helps plants fight off infections by binding to a plant protein and getting activated by a molecule called ADP.

Methodology

The study used crystallography to determine the structure of AvrB bound to RIN4 and ADP, along with functional assays in plants.

Limitations

The study does not explore the full range of plant responses to AvrB or the potential for other host factors involved in the phosphorylation process.

Digital Object Identifier (DOI)

10.1371/journal.ppat.0030048

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