Golgi complex protein modification

Golgi complex. A complex and dynamic membranous organelle of eukaryotic cells. Golgi bodies function in the posttranslational modification (gly-cosylation) and secretion of proteins or insertion into membranes. Composed of cis, medial and trans compartments, as well as a less well defined trans-golgi network. ... 

As discussed previously, N-terminal ER signal sequences are cleaved from secretory proteins and type 1 membrane proteins in the ER. Some proteins also undergo other specific proteolytic cleavages in the Golgi complex or forming secretory vesicles. We cover these cleavages, as well as carbohydrate modifications that occur primarily or exclusively in the Golgi complex, in the next chapter. 

The RER is involved in the synthesis of certain proteins. Ribosomes attached to the membranes of the RER give them their rough appearance. Proteins produced on these ribosomes enter the lumen of the RER, travel to the Golgi complex in vesicles, and are subsequently either secreted from the cell, sequestered within membrane-enclosed organelles such as lysosomes, or embedded in the plasma membrane. Posttranslational modifications of these proteins, such as the initiation of N-linked glycosylation and the addition of GPl anchors, occur in the RER. In contrast, proteins encoded by the nucleus and found in the cytosol, peroxisomes, or mitochondria are synthesized on free ribosomes in the cytosol and are seldom modified by the attachment of oligosaccharides. 

The Golgi apparatus is a complex of folded membranes, which is involved in the post-translational modification of proteins. 

The Golgi apparatus (3) is a complex network, also enclosed, consisting of flattened membrane saccules ( cisterns ), which are stacked on top of each other in layers. Proteins mature here and are sorted and packed. A distinction is made between the ds, medial, and trans Golgi regions, as well as a trans Golgi network (tGN). The post-translational modification of proteins, which starts in the ER, continues in these sections. 

The Golgi apparatus and lysosomes are important intracellular organelles that relate to the molecules of Combo Circle. Ihe Golgi apparatus is important in the modification of proteins during their synthesis and in the construction and packaging of complex macromolecules. Lysosomes are important in the degradation of complex macromolecules. 

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