Question

Which of the following is a mechanism for regulating protein activity?

a. proteolytic processing
b. phosphorylation/dephosphorylation
c. ligand binding
d. b and c
e. all of the above

Answer 1

The mechanisms for regulating protein activity include proteolytic processing, phosphorylation/dephosphorylation, and ligand binding. All options listed contribute to cellular regulation of proteins, making 'all of the above' the correct answer.

Step-by-step explanation:

Regulating protein activity is a critical aspect of cellular function and can be accomplished through several mechanisms. The options provided in the question relate to:

• Proteolytic processing, which refers to the proteolytic cleavage of an inactive polypeptide to release an active protein component.
• Phosphorylation/dephosphorylation, which involves adding or removing phosphate groups to proteins in order to alter their stability and activity. This is accomplished by enzymes such as kinases and phosphatases. Phosphorylation can affect translation, RNA shuttling, RNA stability, and post-transcriptional modification of proteins.
• Ligand binding, which can regulate protein activity by activating or inhibiting the protein when the ligand binds. Such binding can induce conformational changes in the protein or alter its ability to interact with other molecules.

Therefore, the answer is e. all of the above as each mechanism listed contributes to the regulation of protein activity.