Mitochondria supply ATP to the ER through a mechanism antagonized by cytosolic Ca².

ABSTRACT: The endoplasmic reticulum (ER) imports ATP and uses energy from ATP hydrolysis for protein folding and trafficking. However, little is known about how this vital ATP transport occurs across the ER membrane. Here, using three commonly used cell lines (CHO, INS1 and HeLa), we report that ATP enters the ER lumen through a cytosolic Ca²⁺-antagonized mechanism, or CaATiER (Ca²⁺-Antagonized Transport into ER). Significantly, we show that mitochondria supply ATP to the ER and a SERCA-dependent Ca²⁺ gradient across the ER membrane is necessary for ATP transport into the ER, through SLC35B1/AXER. We propose that under physiological conditions, increases in cytosolic Ca²⁺ inhibit ATP import into the ER lumen

SUBMITTER: Yong J 

PROVIDER: S-EPMC6763289 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature