Question

Phosphorylation, ubiquitination, acetylation, and sumoylation are all examples of post-translational modifications. Generally, what do these modifications do?

A) Increase protein synthesis
B) Regulate gene expression
C) Alter protein function or stability
D) Enhance mRNA transcription

Answer 1

Post-translational modifications like phosphorylation, ubiquitination, acetylation, and sumoylation generally alter protein function or stability, and can impact key cellular processes, from gene expression to protein degradation. The correct option is C.

Step-by-step explanation:

Phosphorylation, ubiquitination, acetylation, and sumoylation are examples of post-translational modifications which generally serve to alter protein function or stability. These modifications can influence various cellular processes, such as enzyme activity, protein-protein interactions, and the location of proteins within the cell.

For instance, phosphorylation can impact gene expression by altering transcription factor activity, changing nuclear shuttling, influencing RNA stability, and modulating translation. Modifications like ubiquitination often target proteins for degradation, thereby regulating the amount of protein present in the cell and contributing to the turnover of cellular proteins.