Plasma membrane mediated GLUT10 mitochondrial targeting regulates intracellular ascorbic acid homeostasis

Intracellular ascorbic acid (AA) regulation is essential for connective tissue homeostasis; however, the precise mechanisms governing AA homeostasis during cellular stress remain poorly understood. Here, we identify an oxidative stress-induced glucose transporter 10 (GLUT10) intracellular trafficking mechanism that regulates AA homeostasis via a noncanonical route from the endoplasmic reticulum (ER) to the plasma membrane (PM) and ultimately to mitochondria. This mechanism bridges the traditionally considered spatially and mechanistically distinct pathways of endomembrane system trafficking and mitochondria targeting. Using live-cell imaging and complementary biochemical approaches, we demonstrate that oxidative stress drives this redistribution. Increased PM localization of GLUT10 enhances the uptake of dehydroascorbic acid (DHA), the oxidized form of AA, thereby sustaining intracellular AA levels. The disruption of this trafficking pathway impairs AA homeostasis. Our findings reveal previously unrecognized localization of GLUT10 at the PM and endosomes and uncover endomembrane-mitochondria communication that maintains intracellular AA homeostasis and supports adaptation to oxidative stress.