Fig. 2
From: Reevaluating Golgi fragmentation and its implications in wound repair
Illustrates the canonical mechanism for maintaining GA structure. Top, canonical GA maintains a stacked cisternae structure through the assistance of the structural proteins and regulates the balance of retrograde and anterograde transport to and from ER. In normal GA, GRASP 65 and GRASP 55 exist as dimers, providing adhesive force to maintain the stacks. Syntaxin5 (syn5) plays a crucial role in the assembly of vesicular-tubular pre-Golgi intermediates and cargo delivery to the Golgi. GM130, working alongside giantin and p115, acts as a tether, facilitating vesicle fusion to the GA. During GA fragmentation, GRASP 65 and 55 become phosphorylated, existing as monomers. GM130 undergoes polyubiquitination, targeting it for proteasomal degradation, leading to decreased vesicle fusion with the GA membrane. Syn5 is deubiquitinated by VCIP135, impairing its interaction with BET1 and promoting GA fragmentation. Below, GA fragmentation is an accumulative result that causes unbalanced retrograde and anterograde transport. A small arrow indicates decreased ER-Golgi anterograde transport. A large arrow indicates increased retrograde ER-Golgi retrograde transport. In canonical GA, the system should maintain the sorting, organized trafficking, and protein modification mechanism in the cell. Conversely, in the fragmented GA, there are defects in sorting, accelerated trafficking, and impaired protein modifications