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 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 acupatch 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 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 sophie allport bee curtains have evolved a unique system to support ER-to-Golgi transport despite intracellular motility.