Fig. 6
Phosphorylation on RGS1 Ser431 is required for flg22-triggered de-repression of immune signaling. a Ser431 phosphorylation is required for dynamic regulation of RGS1CT–FLS2 interaction by flg22. WT protoplasts expressing the indicated constructs were treated with flg22, and co-IP was performed to determine RGS1CT–FLS2 interaction. b Ser431 phosphorylation is required for dynamic regulation of RGS1CT–XLG2 interaction by flg22. WT protoplasts expressing the indicated constructs were treated with flg22, and co-IP was performed to determine RGS1CT–XLG2 interaction. c RGS1 Ser431 phosphorylation is required for flg22-induced XLG2CT–AGB1 dissociation. XLG2CT-FLAG and AGB1-HA were co-expressed in protoplasts along with RGS1-HA or RGS1S431A-HA, treated with or without flg22, and XLG2CT–AGB1 interaction was detected by co-IP assays. d The GTPase accelerating activity of RGS1 is not affected by Ser431 mutation. HIS-GPA1 protein was incubated with RGS1CT-HIS or RGS1S431A-HIS protein in reaction buffer containing [α32P]GTP. The hydrolyzation of GTP was detected by autoradiograph. e Phospho-mimicking mutations in Ser428/431/435/436 is sufficient to trigger RGS1 dissociation from FLS2. WT protoplasts expressing the indicated constructs were treated with flg22, and co-IP was performed to detect RGS1CT–FLS2 interaction. f Phospho-mimicking mutations in Ser428/431/435/436 is sufficient to trigger XLG2–AGB1 dissociation. XLG2CT-FLAG and AGB1-HA were co-expressed in protoplasts along with RGS1-HA or RGS14D-HA (S428D, S431D, S435D, and S436D). Protoplasts were then treated with or without flg22, and XLG2CT–AGB1 interaction was detected by co-IP assays. The experiments were performed two (b, e, f) or three (a, c, d) times with similar results
