Figure 6. Model for G protein-coupled FLS2 signaling.
In the pre-activation state, the heterotrimeric G proteins composed of XLG2/3, AGB1, and AGG1/2 interact with the FLS2-BIK1 complex. Stimulation by flg22 induces BAK1-FLS2 interaction and activation of the receptor complex. This leads to the activation of the G proteins and phosphorylation of XLG2 in the N terminus. The activated G proteins dissociate from the receptor complex and regulate RbohD and other downstream effectors to positively modulate immune responses.