The Golgi complex has a characteristic morphology – flattened, disklike, membranous cisternae with dilated rims, and associated tubules. The cisternae have a diameter of 0.5 to 1 micrometer, stacked in an ordered manner and a Golgi stack contains fewer than eight cisternae. There are several thousand distinct types of stacks depending on the cell type. The Golgi stacks are interconnected by membranous tubules to form a single, large ribbon-like complex adjacent to the cell nucleus.
The Golgi complex is divided into several compartments functionally. The compartments are arranged from cis to trans, entry to exit end of the stacks respectively. The cis part of the organelle is composed of an interconnected network of tubules called the cis Golgi network (CGN). The CGN functions as a sorting station where proteins are either shipped back to the ER or allowed to the next Golgi station. The trans Golgi network (TGN) consists of a distinct network of tubules and vesicles. Here, the proteins are segregated into different types of vesicles that are destined to the plasma membrane or to intracellular processes. The membranous elements of the Golgi complex are mechanically supported by a variety of proteins composed scaffold or peripheral membrane system. Such Golgi scaffold is linked to motor proteins that direct the movement of vesicles and tubules entering and exiting the Golgi complex.
- The key role of the Golgi complex is an assembly of the carbohydrate component of glycoproteins and glycolipids.
- Each of the various Golgi cisternae of a stack has distinct types of enzymes. Large number of cargo carrying vesicles bud off the cis side of the Golgi complex and fuse at a trans position of the stack.
- The very existence of Golgi complex is to maintain the continual influx of transport carrirers from the endoplasmic reticulum. The materials that are produced by the endoplasmic reticulum travel through the Golgi apparatus and are released through Golgi-asscoiated vesicles targetting various compartment of the cell.
Image credit: https://openstax.org/