Evolutionarily conserved BON1 regulates the basal cytosolic Ca²⁺ level by calmodulin-independent activation of Ca²⁺ pumps in <i>Arabidopsis</i>.

ABSTRACT: Plasma membrane-localized autoinhibited Ca²⁺ pumps are essential for maintaining basal cytosolic Ca²⁺ levels for regulating growth processes and environmental responses. These pumps are known to be activated by calmodulins to maintain Ca²⁺ homeostasis in plants and animals. Here, we demonstrate that the evolutionarily conserved copine protein BON1 is critical for maintaining low cytosolic Ca²⁺ concentrations by directly regulating two plasma membrane-localized Ca²⁺ pumps ACA8 and ACA10 in Arabidopsis. BON1 interacts with a region within the N-terminal domain of ACA8 and ACA10, preceding the calmodulin binding sites, and stimulates ACA8 activity. This activation can occur without calmodulin binding, indicating that BON1 and calmo

SUBMITTER: Li Z 

PROVIDER: S-EPMC12167975 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature