How does Golgi apparatus modify proteins?

The Golgi apparatus modifies proteins through a series of enzymatic processes that prepare them for their final function and destination. Proteins synthesized in the rough endoplasmic reticulum (RER) are transported to the Golgi in vesicles, where they undergo further processing.

Inside the Golgi, proteins pass through different regions called cisternae (cis, medial, and trans). During this transit, they are chemically modified. One of the most important modifications is glycosylation, where carbohydrate groups are added to proteins, forming glycoproteins. Other modifications may include phosphorylation, sulfation, and cleavage of specific segments.

These modifications are crucial for protein stability, activity, and recognition. The Golgi also tags proteins with specific molecular signals that determine their final destination, such as lysosomes, the cell membrane, or secretion outside the cell.

After processing, proteins are packaged into vesicles and transported to their target locations. This ensures proper distribution and functioning within or outside the cell.

Overall, the Golgi apparatus acts as a processing and sorting center, ensuring that proteins are correctly modified, labeled, and delivered.