The golgin GMAP-210 is required for efficient membrane trafficking in the early secretory pathway

Abstract

Golgins are coiled-coil proteins that participate in membrane tethering events at the Golgi apparatus. Golgin-mediated tethering is thought to be important for vesicular trafficking and Golgi organization. However, the degree to which individual golgins contribute to these processes is poorly defined, and it has been proposed that golgins act in a largely redundant manner. Previous studies on the golgin GMAP-210, which is mutated in the rare skeletal disorder achondrogenesis type 1A, have yielded conflicting results regarding its involvement in trafficking. Here, we re-investigated the trafficking role of GMAP-210, and find that it is indeed required for efficient trafficking in the secretory pathway. GMAP-210 acts at both the ERGIC and Golgi apparatus during anterograde trafficking, and is also required for retrograde trafficking to the endoplasmic reticulum. Using co-depletion experiments, we also find that GMAP-210 acts in a partially redundant manner with the golgin GM130 to ensure efficient anterograde cargo delivery to the cis-Golgi. In summary, our results indicate a role for GMAP-210 in several trafficking steps at the ER/Golgi interface, some of which are partially redundant with another golgin, namely GM130.