Question

Proteins entering the cis Golgi network can do which of the following?

A. They can either move onward through the Golgi stack or be returned to the ER.
B. They can either move backward through the Golgi stack or be sent to the plasma
membrane.
C. They are sorted according to whether they are destined for lysosomes or for the cell
surface.

Answer 1

In the cis Golgi network, proteins can either progress through the Golgi stack or be returned to the ER, undergoing modifications like glycosylation and phosphorylation that signal their final destination, such as lysosomes or the plasma membrane.

Step-by-step explanation:

Proteins entering the cis Golgi network can either move onward through the Golgi stack or be returned to the endoplasmic reticulum (ER). During their transit through the Golgi apparatus, proteins are processed within its stacks, undergoing modifications such as glycosylation and phosphorylation. These modifications often involve the addition of sugar chains or phosphate groups, which can serve as signals for sorting the proteins to their final destinations. For instance, the addition of mannose-6-phosphate is a signal for proteins to be directed to lysosomes. This sorting process is crucial as proteins are moved from the cis- to the trans-Golgi network, where they are finally packaged into vesicles and sent to their destination, such as the plasma membrane or other organellar membranes.