Golgi Apparatus

In the eukaryotic cell, next to the ER, is the Golgi apparatus, a stack of disc-shaped membrane-bound compartments called cisternae with two distinct faces, cis and trans.

Each cisterna contains unique enzymes and trafficking proteins that process proteins and lipids as they move through the Golgi.

Proteins and lipids from the ER enter the cis-Golgi and then move through the medial cisternae, where they are chemically modified by adding sugars, phosphates, or sulfates.

These modifications make proteins functional at their target organelle. Farthest from the ER is the trans-Golgi network, where the molecules are sorted according to their final destination, which can be the cell membrane, lysosomes, or the extracellular matrix.

During sorting, each molecule is tagged with a signal sequence that will be recognized by a receptor on its destination organelle.

Finally, the cargo molecules are packaged in transport vesicles and dispatched to their destinations within the cell.