Ca²⁺ efflux facilitated by co-transport of inorganic phosphate anion in the H⁺/Ca²⁺ antiporter YfkE.

ABSTRACT: Ca²⁺ is an important signaling messenger. In microorganisms, fungi, and plants, H⁺/Ca²⁺ antiporters (CAX) are known to play key roles in the homeostasis of intracellular Ca²⁺ by catalyzing its efflux across the cell membrane. Here, we reveal that the bacterial CAX homolog YfkE transports Ca²⁺ in two distinct modes: a low-flux H⁺/Ca²⁺ exchange mode and a high-flux mode in which Ca²⁺ and phosphate ions are co-transported (1:1) in exchange for H⁺. Coupling with phosphate greatly accelerates the Ca²⁺ efflux activity of YfkE. Our studies reveal that Ca²⁺ and phosphate bind to adjacent sites in a central translocation pathway and lead to mechanistic insights that explain how t

SUBMITTER: Niu W 

PROVIDER: S-EPMC10227063 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature