The addition of ubiquitin to a protein typically marks it for which of the following processes?

• A. Protein degradation
• B. Protein folding
• C. Protein synthesis
• D. Protein transport

Answer: (A)

Verified step by step guidance

1. Understand the role of ubiquitin in cellular processes. Ubiquitin is a small regulatory protein that can be attached to other proteins to modify their function or fate.
2. Recognize that ubiquitination is a post-translational modification where ubiquitin molecules are covalently attached to a substrate protein.
3. Learn that the most common outcome of ubiquitination is targeting the protein for degradation. This process is carried out by the proteasome, a large protein complex that degrades and recycles proteins.
4. Differentiate between the processes listed: Protein degradation involves breaking down proteins into amino acids, protein folding is the process of a protein achieving its functional three-dimensional structure, protein synthesis is the creation of proteins from amino acids, and protein transport involves moving proteins to different locations within or outside the cell.
5. Conclude that the addition of ubiquitin to a protein typically marks it for protein degradation, as ubiquitin acts as a signal for the proteasome to recognize and degrade the tagged protein.