Clathrin adaptor EPSIN1 ( EPS1 ) modulates plasma membrane abundance of PLEIOTROPIC DRUG RESISTANCE PDR9 for effective hormone homeostasis

The cellular machinery that directs the indole-3-butyric acid (IBA) effluxer PLEIOTROPIC DRUG RESISTANCE 9 (PDR9) to the outer plasma membrane (PM) domain of the root epidermis remains poorly understood. This study combines biochemical fractionation, live-cell imaging, and physiological assays to identify the trans-Golgi Network-localized clathrin adaptor EPSIN1 (EPS1) as a novel modulator of PDR9 abundance at the root PM for IBA-dependent physiological processes. These findings expand EPS1's roles from plant immunity to hormone homeostasis, thereby advancing the limited understanding of biological functions for plant EPSINs.