What is the Difference Between Cis and Trans Face of Golgi Apparatus

The main difference between cis and trans face of Golgi apparatus is that the vesicles that leave the endoplasmic reticulum fuse to the Golgi apparatus from its cis face whereas the vesicles that leave the Golgi apparatus exist from its trans face. Furthermore, the cis face receives unmodified or immature proteins while the modified or mature proteins exit from the trans face.

Cis and trans face are the two faces of the Golgi apparatus. Moreover, Golgi apparatus is present in most eukaryotic cells, facilitating the packaging and transport of proteins to their destinations within the cell.

Key Areas Covered

1. What is the Cis Face of Golgi Apparatus
     – Definition, Shape, Role
2. What is the Trans Face of Golgi Apparatus
     – Definition, Shape, Role
3. What are the Similarities Between Cis and Trans Face of Golgi Apparatus
     – Outline of Common Features
4. What is the Difference Between Cis and Trans Face of Golgi Apparatus
     – Comparison of Key Differences

Key Terms

Cis Face, Cisternae, Golgi Apparatus, Protein Packaging, Trans Face, Vesicles

What is the Cis Face of Golgi Apparatus

Cis face is one of the three networks of the Golgi apparatus; they are the cis Golgi network (CGN), medial compartment, and trans-Golgi network (TGN). The main function of the cis face of the Golgi apparatus is to receive proteins and lipids from the endoplasmic reticulum. Therefore, the CGN always faces the endoplasmic reticulum.

Figure 1: Cis and the Trans Face of Golgi Apparatus

Since the cis face receives vesicles, this face is always called the forming face. Also, it is the initial packaging stage of substances.

What is the Trans Face of Golgi Apparatus

The trans face or the TGN is the final phase of the Golgi apparatus. The main function of TGN is to produce vesicles, which contain mature proteins or lipids. Immature proteins and lipids travel to the medial compartment of the Golgi apparatus to mature. There, these substances undergo a number of modifications including post-translational modifications, glycosylation and phosphorylation.

Figure 1: Golgi Apparatus Function

Furthermore, three types of vesicles leave the trans face of the Golgi apparatus: exocytotic vesicles, secretory vesicles, and lysosomal vesicles. The exocytotic vesicles contain proteins released extracellularly like antibodies while secretory vesicles contain substances like neurotransmitters, which are to be released to the extracellular space. Moreover, lysosomes contain digestive enzymes responsible for phagocytosis or membrane proteins, which are going to fuse with the membrane.

Similarities Between Cis and Trans Face of Golgi Apparatus

• Cis and trans face are the two faces of the Golgi apparatus.
• Both cis and trans face are made up of cisternae. These cisternae can either form or fuse to vesicles.
• Moreover, they play a key role in protein maturation and transport within the cell.
• Also, most substances matured inside the Golgi apparatus belong to the outward secretory pathway; going out of the cell surface.

Difference Between Cis and Trans Face of Golgi Apparatus

Definition

The cis face of Golgi apparatus is the receiving face of the Golgi apparatus to which the vesicles from the endoplasmic reticulum empty their content. Whereas, the trans face of Golgi apparatus is the existing face of the Golgi apparatus from which the vesicles leave the Golgi apparatus. These definitions explain the main difference between cis and trans face of Golgi apparatus.

Shape

Based on the shape, the difference between cis and trans face of Golgi apparatus is that the cis face of Golgi apparatus is convex in shape while the trans face of Golgi apparatus is concave in shape.

Direction

Also, the cis face of Golgi apparatus faces the endoplasmic reticulum while the trans face of Golgi apparatus faces the cytoplasm. Thus, this is another difference between cis and trans face of Golgi apparatus.

Function

Moreover, the cis face of the Golgi apparatus receives vesicles from the endoplasmic reticulum while the vesicles leave the Golgi apparatus from its trans face. Functionally, this is the difference between cis and trans face of Golgi apparatus.

Type of Proteins

Another major difference between cis and trans face of Golgi apparatus is that cis face of the Golgi apparatus receives immature or unmodified proteins while mature or the modified proteins leave the trans face of Golgi apparatus.

Conclusion

In conclusion, the cis face of Golgi apparatus is the receiving face of the Golgi apparatus to which the vesicles from the endoplasmic reticulum empty their content while the trans face of Golgi apparatus is the existing face of the Golgi apparatus from which the vesicles leave the Golgi apparatus. Therefore, immature proteins enter the Golgi apparatus from its cis face and leave the Golgi apparatus from its trans face. Hence, the main difference between cis and trans face of Golgi apparatus is their role in protein maturation.

Reference:

1. Cooper GM. The Cell: A Molecular Approach. 2nd edition. Sunderland (MA): Sinauer Associates; 2000. The Golgi Apparatus. Available Here

Image Courtesy:

1. “Golgi apparatus” By Britannica – 2008 Encyclopedia Britannica ,INC (CC BY-SA 4.0) via Commons Wikimedia
1. “0314 Golgi Apparatus” By OpenStax – (CC BY 4.0) via Commons Wikimedia