The Magnaporthe oryzae Effector AvrPiz-t Targets the RING E3 Ubiquitin Ligase APIP6 to Suppress Pathogen-Associated Molecular Pattern–Triggered Immunity in Rice

SummaryPlant immunity is tightly controlled by a complex and dynamic regulatory network, which ensures optimal activation upon detection of potential pathogens. Accordingly, each component of this network is a potential target for manipulation by pathogens. Here, we report that RipAC, a type III-secreted effector from the bacterial pathogen Ralstonia solanacearum, targets the plant E3 ubiquitin ligase PUB4 to inhibit pattern-triggered immunity (PTI). PUB4 plays a positive role in PTI by regulating the homeostasis of the central immune kinase BIK1. Before PAMP perception, PUB4 promotes the degradation of non-activated BIK1, while, after PAMP perception, PUB4 contributes to the accumulation of activated BIK1. RipAC leads to BIK1 degradation, which correlates with its PTI-inhibitory activity. RipAC causes a reduction in pathogen-associated molecular pattern (PAMP)-induced PUB4 accumulation and phosphorylation. Our results shed light on the role played by PUB4 in immune regulation, and illustrate an indirect targeting of the immune signalling hub BIK1 by a bacterial effector.

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Faculty Opinions recommendation of The Arabidopsis C3H2C3-type RING E3 ubiquitin ligase AtAIRP1 is a positive regulator of an abscisic acid-dependent response to drought stress.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.6881957.7063055 ◽

2010 ◽

Author(s):

Hanjo Hellmann

Keyword(s):

Abscisic Acid ◽

Drought Stress ◽

Ubiquitin Ligase ◽

E3 Ubiquitin Ligase ◽

Positive Regulator ◽

Ring E3

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The von Hippel–Lindau Cullin-RING E3 ubiquitin ligase regulates APOBEC3 cytidine deaminases

Translational Research ◽

10.1016/j.trsl.2021.05.002 ◽

2021 ◽

Author(s):

Gaël K. Scholtès ◽

Aubrey M. Sawyer ◽

Cristina C. Vaca ◽

Isabelle Clerc ◽

Meejeon Roh ◽

...

Keyword(s):

Ubiquitin Ligase ◽

E3 Ubiquitin Ligase ◽

Cytidine Deaminases ◽

Von Hippel Lindau ◽

Ring E3

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Identification of a PGXPP degron motif in dishevelled and structural basis for its binding to the E3 ligase KLHL12

Open Biology ◽

10.1098/rsob.200041 ◽

2020 ◽

Vol 10 (6) ◽

pp. 200041 ◽

Cited By ~ 1

Author(s):

Zhuoyao Chen ◽

Gregory A. Wasney ◽

Sarah Picaud ◽

Panagis Filippakopoulos ◽

Masoud Vedadi ◽

...

Keyword(s):

Ubiquitin Ligase ◽

Molecular Mechanisms ◽

Hydrophobic Interactions ◽

E3 Ubiquitin Ligase ◽

Structural Basis ◽

E3 Ligases ◽

Kelch Domain ◽

Ring E3 Ligases ◽

Ring E3 ◽

New Protein

Wnt signalling is dependent on dishevelled proteins (DVL1-3), which assemble an intracellular Wnt signalosome at the plasma membrane. The levels of DVL1-3 are regulated by multiple Cullin-RING E3 ligases that mediate their ubiquitination and degradation. The BTB-Kelch protein KLHL12 was the first E3 ubiquitin ligase to be identified for DVL1-3, but the molecular mechanisms determining its substrate interactions have remained unknown. Here, we mapped the interaction of DVL1-3 to a ‘PGXPP' motif that is conserved in other known partners and substrates of KLHL12, including PLEKHA4, PEF1, SEC31 and DRD4. To determine the binding mechanism, we solved a 2.4 Å crystal structure of the Kelch domain of KLHL12 in complex with a DVL1 peptide that bound with low micromolar affinity. The DVL1 substrate adopted a U-shaped turn conformation that enabled hydrophobic interactions with all six blades of the Kelch domain β-propeller. In cells, the mutation or deletion of this motif reduced the binding and ubiquitination of DVL1 and increased its stability confirming this sequence as a degron motif for KLHL12 recruitment. These results define the molecular mechanisms determining DVL regulation by KLHL12 and establish the KLHL12 Kelch domain as a new protein interaction module for a novel proline-rich motif.

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