Membrane-Localized Extra-Large G Proteins and Gβγ of the Heterotrimeric G Proteins Form Functional Complexes Engaged in Plant Immunity in Arabidopsis

EXTRA-LARGE G PROTEINs Interact with E3 Ligases PUB4 and PUB2 and Function in Cytokinin and Developmental Processes

“…2A). The subcellular localization patterns of the XLG proteins are consistent with recent reports (Chakravorty et al, 2015;Maruta et al, 2015). PUB4 was previously reported to be localized in cytoplasm, whereas the interactions between PUB2/4 and XLGs would suggest that PUB2 and PUB4 might also be localized in the plasma membrane.…”

“…However, under normal conditions, the xlg1-1 xlg2-1 xlg3-1 triple mutant in the previous reports lacked an obvious morphological phenotype Pandey et al, 2008;Zhu et al, 2009;Chakravorty et al, 2015;Maruta et al, 2015). The xlg1-1 allele is considered to be a knockdown as XLG1 expression was still detectable in the mutant, although at a low level .…”

“…Like canonical Ga proteins, the C-terminal Ga-like domain has the ability to bind and hydrolyze GTP in the presence of Ca 2+ instead of Mg 2+ (Heo et al, 2012). All three XLGs were found predominantly localized in the plasma membrane, whereas XLG2 and XLG3 were also found in nuclei (Chakravorty et al, 2015;Maruta et al, 2015). XLGs interact and form complexes with Gbg and have been reported to share similar function with Gb and Gg in many developmental processes and stress responses (Zhu et al, 2009;Chakravorty et al, 2015;Maruta et al, 2015).…”

“…All three XLGs were found predominantly localized in the plasma membrane, whereas XLG2 and XLG3 were also found in nuclei (Chakravorty et al, 2015;Maruta et al, 2015). XLGs interact and form complexes with Gbg and have been reported to share similar function with Gb and Gg in many developmental processes and stress responses (Zhu et al, 2009;Chakravorty et al, 2015;Maruta et al, 2015). Like agb1, xlg3 mutants were impaired in the root waving and skewing response and were hypersensitive to ethylene ).…”

“…An xlg triple mutant, agb1, and agg1/2 also showed increased sensitivity to salt, tunicamycin, and D-Glc and had an increased stomatal density (Chakravorty et al, 2015). XLGs, AGB1, and AGG1/2 are known to be positive regulators of defense responses to several pathogens, and their loss-of-function mutants were compromised in the pathogen-associated molecular pattern-triggered oxidative burst, in disease resistance, or in BIR1-mediated defense signaling and programmed cell death (Zhu et al, 2009;Delgado-Cerezo et al, 2012;Lee et al, 2013;Liu et al, 2013;Maruta et al, 2015;Liang et al, 2016). XLG2 also interacts with RELATED TO VERNALIZATION1 (RTV1) and is involved in RTV1-mediated flowering time control (Heo et al, 2012).…”