Isoform-specific tethering links the Golgi ribbon to maintain compartmentalization

• DOI: 10.1091/mbc.e13-07-0395
• Publication Date: 2013-11-14T04:49:04Z
• Authors: Timothy Jarvela; Adam D. Linstedt
• Keywords: Tethering; Compartmentalization (fire protection); Golgi membrane

Homotypic membrane tethering by the Golgi reassembly and stacking proteins (GRASPs) is required for lateral linkage of mammalian ministacks into a ribbon-like network. Although GRASP65 GRASP55 are specifically localized to cis medial/trans cisternae, respectively, it unknown whether each GRASP mediates cisternae-specific such specificity necessary compartmentalization. Here was tagged with KillerRed (KR), expressed in HeLa cells, inhibited 1-min exposure light. Significantly, inactivation either unlinked ribbon, immediate effect GRASP65-KR loss cis- rather than trans-Golgi integrity, whereas GRASP55-KR first affected trans- not cis-Golgi. Thus appears play direct role linking continuous To test consequence tethering, we generated membranes single on all cisternae. Remarkably, exhibited full connectivity wild-type ribbons but were decompartmentalized defective glycan processing. isoforms link analogous cisternae ensure compartmentalization proper