Cisternal Maturation vs. Vesicular Transport

The Golgi apparatus is an organelle involved in protein targeting; specifically, Golgi-associated proteins are destined for the plasma membrane or secretion. To learn more about other kinds of protein targeting, visit this article: https://www.sixfootscience.com/brain-snips/where-to-how-newly-translated-proteins-find-their-new-cellular-home.

The cisternal maturation model is one proposed way by which the Golgi facilitates protein-filled vesicle exocytosis for either secretion or insertion into the plasma membrane. This model relies on retrograde transport, and the Golgi’s cisternae are the things that are “maturing.” Vesicles from the ER converge with vesicles that move backwards from the cis Golgi. This becomes the new cis Golgi. All the layers shift forward towards the plasma membrane. The “most mature” layer fuses with the PM and exocytosis of proteins ensues. The next load from the ER leads to the next exocytosis. In this way, vesicles are inserted in the plasma membrane.

In the vesicular transport model, the vesicle is passed forward between layers of the Golgi, and the vesicle exits out the trans Golgi. It fuses with the PM, and this is how it is either secreted or inserted in the plasma membrane.

Here is a great visual, if my words didn’t make much sense. Also, the music is fire:

https://www.youtube.com/watch?v=WCc57iFPwjk - this is literally the only video I watched for this lol. It makes total sense if you have a basic understanding of protein synthesis.

Bonus: FUN USABO PROBLEM! Source: 2018 Semis.