RAF-like protein kinase signaling modules control plant proton pump activity.

Proton extrusion by plasma membrane autoinhibited H+ ATPases (AHAs) enables stomatal opening and plant cell expansion. Takase et al. demonstrated that heterocomplexes of C5 and C7 RAF-like kinases activate AHAs. The modular nature of C5-C7 RAF complexes allows cell-type-specific responses to stimuli, such as stomatal guard-cell CO2 levels.