Reversible Controlled Aggregation of Golgi Resident Enzymes to Assess Their Transport/Dynamics Along the Secretory Pathway.

Golgi resident enzymes (GREs) are type II membrane proteins that are responsible for the processing of lipids and proteins within the Golgi stack, mostly by catalyzing the formation of long chains of different sugars bound to their substrates at specific positions. After synthesis and folding, GREs leave the ER to reach the Golgi complex where they are distributed along the Golgi stack in a fashion that reflects the sequential order of the sugar addition reactions they execute. Remarkably, the position of GREs within the stack is not stable; rather, the GREs appear to move rapidly across Golgi cisternae, perhaps to maintain the correct reaction order during the flux of traffic. It would thus be important to understand their dynamics, but methods to analyze their mobility within the stack are lacking. Here, we describe a tool to induce the reversible and controlled aggregation of GREs that can be used to study the ER-to-Golgi transport and intra Golgi dynamics of these enzymes (Rizzo et al., J Cell Biol 201:1027-1036, 2013; Tewari et al., Mol Biol Cell 26:4427-4437, 2015).