Figure 2. The interaction between GI and components of the SOS pathway. GI acts as a negative regulator of SOS1 activity in the absence of elevated [NaCl]. NaCl-induced degradation of GI leads to SOS2-initiated activation of SOS1 by phosphorylation, while SOS1 is constitutively active in the absence of GI (gi). Salt-dependent degradation of GI or its absence retard or abolish the progression toward flowering.