反转运蛋白
流出
反转运蛋白
磷酸盐
细胞内
化学
平衡
焊剂(冶金)
生物物理学
离子运输机
生物化学
染色体易位
细胞生物学
膜
生物
基因
有机化学
作者
Wei Niu,Wenchang Zhou,Shuo Lu,Trung Vu,Vasanthi Jayaraman,José D. Faraldo‐Gómez,Lei Zheng
标识
DOI:10.1038/s42003-023-04944-6
摘要
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 this CAX alters its conserved alpha-repeat motifs to adopt phosphate as a specific "transport chaperon" for Ca2+ translocation. This finding uncovers a co-transport mechanism within the CAX family that indicates this class of proteins contributes to the cellular homeostasis of both Ca2+ and phosphate.
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