Plant-specific tail-anchored coiled-coil protein MAG3 stabilizes Golgi-associated ERESs to facilitate protein exit from the ER

Plant-specific tail-anchored coiled-coil protein MAG3 stabilizes Golgi-associated ERESs to facilitate protein exit from the ER

Blog Article

Abstract Endoplasmic reticulum Salmon exit sites (ERESs) are ER subdomains where coat protein complex II carriers are assembled for ER-to-Golgi transport.We previously proposed a dynamic capture-and-release model of ERESs by Golgi stacks in plants.However, how ERESs and Golgi stacks maintain a stable interaction in plant cells with vigorous cytoplasmic streaming is unknown.

Here, we show that a plant-specific ER transmembrane protein, which we designate as MAG3, plays a crucial role in mediating the capture-and-release of ERESs in Arabidopsis.We isolated a mutant (mag3) defective in protein exit from the ER in seeds.MAG3 localized specifically to the ER-Golgi interface with Golgi-associated ERESs and remained there after ERES Refurbished Espresso Machine (Super-Automatic) release.

MAG3 deficiency caused a reduction in the amount of ERESs associated with each Golgi stack.MAG3 interacted with WPP DOMAIN PROTEINs, which are also plant-specific.These results suggest that plants have evolved a unique system to support ER-to-Golgi transport despite intracellular motility.