VAMP4 and its cognate SNAREs are required for maintaining the ribbon structure of the Golgi apparatus

Abstract Background The Golgi apparatusis at a crossroads between anterograde and retrograde trafficking. It exhibits a twisted ribbon-like network in the juxtanuclear region of vertebrate cells. Vesicle-associated membrane protein4 (VAMP4) is a unique v-SNARE expressed exclusively in trans -Golgi networks (TGN), where it regulates retrograde trafficking from the early endosometo the TGN with its cognateSNARE partners Syntaxin6, Syntaxin16, and Vti1a. Highlight To examine whether VAMP4 plays a role in maintaining the Golgi ribbonstructure, we depleted VAMP4 expression using a small interfering RNA. Depletion of VAMP4 led to fragmentation of the Golgi ribbonin HeLa cells. Immunohistochemical analysis showed that, in the absence of VAMP4, although the Golgi stack length was shortened, Golgi stacking was normal. Furthermore, depletion of the cognateSNARE partners of VAMP4 also disrupted the Golgi ribbonstructure. Microscopy-based analyses showed that Golgi fragmentation did not impair anterograde traffic. Conclusion Our findings suggest that VAMP4 and its cognateSNAREs are required for maintaining the Golgi ribbonstructure by balancing membrane transportbetween the endosomeand TGN.