Membrane-localized extra-large G proteins and Gβγ of the heterotrimeric G proteins form functional complexes engaged in plant immunity in arabidopsis

Maruta, Natsumi, Trusov, Yuri, Brenya, Eric, Parekh, Urvi and Botella, Jose Ramon (2015) Membrane-localized extra-large G proteins and Gβγ of the heterotrimeric G proteins form functional complexes engaged in plant immunity in arabidopsis. Plant Physiology, 167 3: 1004-1016. doi:10.1104/pp.114.255703


Author Maruta, Natsumi
Trusov, Yuri
Brenya, Eric
Parekh, Urvi
Botella, Jose Ramon
Title Membrane-localized extra-large G proteins and Gβγ of the heterotrimeric G proteins form functional complexes engaged in plant immunity in arabidopsis
Journal name Plant Physiology   Check publisher's open access policy
ISSN 1532-2548
0032-0889
Publication date 2015-03-01
Year available 2015
Sub-type Article (original research)
DOI 10.1104/pp.114.255703
Open Access Status Not yet assessed
Volume 167
Issue 3
Start page 1004
End page 1016
Total pages 14
Place of publication Rockville, United States
Publisher American Society of Plant Biologists
Language eng
Abstract In animals, heterotrimeric G proteins, comprising Gα, Gβ, and Gγ subunits, are molecular switches whose function tightly depends on Gα and Gβγ interaction. Intriguingly, in Arabidopsis (Arabidopsis thaliana), multiple defense responses involve Gβγ, but not Gα. We report here that the Gβγ dimer directly partners with extra-large G proteins (XLGs) to mediate plant immunity. Arabidopsis mutants deficient in XLGs, Gβ, and Gγ are similarly compromised in several pathogen defense responses, including disease development and production of reactive oxygen species. Genetic analysis of double, triple, and quadruple mutants confirmed that XLGs and Gβγ functionally interact in the same defense signaling pathways. In addition, mutations in XLG2 suppressed the seedling lethal and cell death phenotypes of BRASSINOSTEROID INSENSITIVE1-associated receptor kinase1-interacting receptor-like kinase1 mutants in an identical way as reported for Arabidopsis Gβ-deficient mutants. Yeast (Saccharomyces cerevisiae) three-hybrid and bimolecular fluorescent complementation assays revealed that XLG2 physically interacts with all three possible Gβγ dimers at the plasma membrane. Phylogenetic analysis indicated a close relationship between XLGs and plant Gα subunits, placing the divergence point at the dawn of land plant evolution. Based on these findings, we conclude that XLGs form functional complexes with Gβγ dimers, although the mechanism of action of these complexes, including activation/deactivation, must be radically different form the one used by the canonical Gα subunit and are not likely to share the same receptors. Accordingly, XLGs expand the repertoire of heterotrimeric G proteins in plants and reveal a higher level of diversity in heterotrimeric G protein signaling.
Keyword Plant Sciences
Plant Sciences
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID DP1094152
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Agriculture and Food Sciences
Official 2016 Collection
 
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