EXTRA-LARGE G proteins interact with E3 ligases PUB4 and PUB2 and function in Cytokinin and Developmental processes

Yiping Wang, Yingying Wu, Boying Yu, Zhao Yin, Yiji Xia*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

58 Citations (Scopus)


Heterotrimeric GTP-binding proteins (G proteins) composed of Gα, Gβ, and Gγ subunits are conserved signal transduction molecules in animals and plants. In Arabidopsis (Arabidopsis thaliana), there are three Ga-like proteins named EXTRA-LARGE G PROTEINs (XLGs) in addition to the canonical Ga protein GPA1. XLGs have been reported to be implicated in multiple pathways, although the underlying mechanisms of their action remain elusive. Here, we report that all three XLGs interact with two closely related plant U-box (PUB) E3 ligases, PUB2 and PUB4. Three XLGs are predominantly localized at the plasma membrane, whereas XLG2 and XLG3 also show nuclear localization. The interactions between PUB2/4 and XLGs suggest that they might function in the same pathways. Indeed, we found that a newly obtained xlg1/2/3 triple knockout mutant, the pub4 mutant, and the pub2/4 double mutant all exhibited defects in cytokinin responses, stamen development, tapetum development, and male fertility. However, the xlg single mutants and the pub2 mutant did not exhibit an obvious defect in these processes, which suggests functional redundancy among the three XLGs and between PUB2 and PUB4. Overexpressing ARR10 to enhance the cytokinin response in pub4 or in the xlg1/2/3 triple mutant partially restored several phenotypes caused by the pub4 and xlg1/ 2/3 mutations. Our findings reveal that the XLGs and PUB2/4 are components in the complex cytokinin signaling networks regulating many developmental and physiological processes.

Original languageEnglish
Pages (from-to)1235-1246
Number of pages12
JournalPlant Physiology
Issue number2
Early online date16 Dec 2016
Publication statusPublished - Feb 2017

Scopus Subject Areas

  • Physiology
  • Genetics
  • Plant Science


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