Figure 8.

PAT10-mediated tonoplast CBL-CIPK module negatively mediated ABA responses during stomatal movement. During stomatal movement, ABA induces [Ca²⁺]_cyt increase through the PM and possibly also internal Ca²⁺ store. Elevated [Ca²⁺]_cyt initiates ABA-induced stomatal closure, including potassium efflux and vacuolar convolution/fragmentation. Elevated [Ca²⁺]_cyt also promotes the activity of CBL2/3-CIPK9/17, whose association at the tonoplast depends on PAT10. The CBL-CIPK module mediates potassium homeostasis at the tonoplast possibly through NHXs, and by doing so prevents further elevation of [Ca²⁺]_cyt.