AAMC FL Practice Exam

What is the role of phosphatase enzymes in cellular processes?

1. Add phosphate groups

2. Remove phosphate groups

3. Transfer phosphate from ATP

4. Facilitate protein folding

The correct answer is: Remove phosphate groups

Phosphatase enzymes play a crucial role in cellular processes primarily by removing phosphate groups from molecules, a process known as dephosphorylation. This activity is essential for regulating various biological functions, including signal transduction, metabolism, and cell cycle progression. Dephosphorylation can actively deactivate or change the activity of proteins, thus providing a mechanism for the rapid modulation of cellular responses to different stimuli. For example, the removal of phosphate groups can lead to the inactivation of certain enzymes, modification of protein interactions, or alteration of protein conformation, which are pivotal processes in maintaining homeostasis within the cell. The other roles mentioned in the options can be clarified as follows: adding phosphate groups is the function of kinases rather than phosphatases, while transferring phosphate from ATP is also a activity associated with kinases. Lastly, facilitating protein folding is not a function of phosphatases but rather associated with chaperone proteins that assist in the proper folding of polypeptides. Hence, the role of phosphatase enzymes specifically revolves around the removal of phosphate groups, enabling significant regulatory functions in various signaling pathways.