A protein called AtPUB19 in plants helps regulate responses to drought and a stress hormone called abscisic acid. When AtPUB19 is overexpressed, plants become more sensitive to abscisic acid, close their stomata (tiny pores on leaves), and become more tolerant to drought. This protein affects the expression of many genes involved in stress responses. Overall, AtPUB19 plays a negative role in controlling drought and abscisic acid responses in Arabidopsis thaliana.