Abstract
Arabidopsis heterotrimeric G proteins regulate diverse plant growth and defense processes by coupling to 7TM AtRGS1 proteins. Although G protein mutants display alterations in response to multiple plant hormones, the underlying mechanism by which G proteins participate in the regulation of hormone responses remains elusive. Here, we show that genetic disruption of Gα and Gβ subunits results in reduced sensitivity to JA treatment. Furthermore, using confocal microscopy, VA-TIRFM, and FRET-FLIM, we provide evidence that stimulation by JA induces phosphorylation- and C-terminus-dependent endocytosis of AtRGS1, which then promotes dissociation of AtRGS1 from AtGPA1. In addition, SPT analysis reveals that JA treatment affects the diffusion dynamics of AtRGS1 and AtRGS1-ΔCt. Taken together, these findings suggest that the JA signal activates heterotrimeric G proteins through the endocytosis of AtRGS1 and dissociation of AtRGS1 from AtGPA1, thus providing valuable insight into the mechanisms of how the G protein system perceives and transduces phytohormone signals.
Highlights
Jasmonates (JAs), which include jasmonic acid and its oxylipin derivatives, are synthesized from the octadecanoid/hexadecanoid pathways and are widely distributed throughout the plant kingdom [1]
We demonstrated that JA induced the endocytosis of AtRGS1 in a phosphorylation- and C-terminus-dependent manner, which in turn led to the dissociation of AtRGS1 from AtGPA1 for activation of downstream signaling
The Heterotrimeric G Protein Complex Is Involved in JA Signaling
Summary
Jasmonates (JAs), which include jasmonic acid and its oxylipin derivatives, are synthesized from the octadecanoid/hexadecanoid pathways and are widely distributed throughout the plant kingdom [1]. AtRGS1, a GPCR-like N-terminal 7TM fused to a regulator of G-protein signaling (RGS) protein, keeps the complex in the inactive state by promoting GTP hydrolysis of AtGPA1 [11,12]. In the presence of glucose, WITH NO LYSINE kinases (WNKs) can phosphorylate AtRGS1 at the C-terminal domain for endocytosis, which is critical to the activation of G protein-mediated sugar signaling and cell proliferation [14,15]. We demonstrated that JA induced the endocytosis of AtRGS1 in a phosphorylation- and C-terminus-dependent manner, which in turn led to the dissociation of AtRGS1 from AtGPA1 for activation of downstream signaling. Our analyses propose a possible role for JA-induced endocytosis of AtRGS1 in G-protein-mediated JA responses and support the hypothesisthat plant hormone signaling might be relayed, in part, by the AtRGS1-G protein pathway
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
