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Updated: May 23, 2026
10:27
Functional Characterization of RING-Type E3 Ubiquitin Ligases In Vitro and In Planta
Published on: December 5, 2019
Nucleotide-dependent switching and RIPb effector recognition of the barley susceptibility factor RACB
Mariam Mohamadi1, Mariem Bradai2, Robert Janowski3
1Bavarian NMR Center (BNMRZ) and Structural Membrane Biochemistry, Dept. of Bioscience, TUM School of Natural Sciences, Technical University of Munich, Garching, Germany.
Communications Biology
|May 21, 2026
Summary
Researchers uncovered the atomic structure of barley RACB, a key plant immune protein. This reveals how RACB switches between active and inactive states and interacts with effector proteins, explaining how pathogens exploit plant defense pathways.
Area of Science:
- Plant biology
- Molecular signaling
- Structural biology
Background:
- ROP proteins are crucial plant signaling molecules regulating growth and immunity.
- Understanding their activation and effector interactions is key to plant defense research.
- Structural insights into ROP GTPases are limited.
Purpose of the Study:
- To elucidate the atomic-resolution structure of barley RACB (a ROP GTPase).
- To understand the structural mechanisms of RACB activation and effector binding.
- To provide molecular insights into plant susceptibility to pathogens.
Main Methods:
- X-ray crystallography
- Nuclear magnetic resonance (NMR) spectroscopy
- Hydrogen-deuterium exchange mass spectrometry (HDX-MS)
- Integrative structural analysis
Main Results:
- High-resolution structures of RACB in inactive and active conformations were determined.
- The conformational flexibility and switching mechanism of RACB were revealed.
- The structure of the active RACB-RIPb complex identified a conserved interaction motif in RIPb.
Conclusions:
- Detailed structural framework for plant Rho-type GTPase signaling.
- Mechanistic insights into how RIPb links RACB to the cytoskeleton for membrane remodeling.
- Molecular basis for pathogen exploitation of ROP-mediated pathways in plants.
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