How would blocking the activity of phosphodiesterase (PDE) affect a cell that responds to hormonal stimulation by the cAMP second messenger system?

Verified step by step guidance

1. Identify the role of phosphodiesterase (PDE) in the cAMP second messenger system. PDE is an enzyme that breaks down cyclic AMP (cAMP) into AMP, thus terminating the signal.
2. Understand the function of cAMP in the cell. cAMP acts as a second messenger that is activated by the binding of a hormone to a receptor, leading to the activation of protein kinase A (PKA) and subsequent cellular responses.
3. Consider the effect of blocking PDE activity. If PDE is inhibited, cAMP levels would remain elevated because it is not being broken down into AMP.
4. Predict the cellular response to elevated cAMP levels. With higher cAMP levels, the activation of PKA would be prolonged, leading to an extended or amplified cellular response to the hormone.
5. Conclude the overall impact on the cell. Blocking PDE would enhance and prolong the effects of hormones that use the cAMP second messenger system, potentially leading to increased cellular activity or prolonged physiological effects.

Key Concepts

Phosphodiesterase (PDE)

Phosphodiesterase (PDE) is an enzyme that breaks down cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are important second messengers in cellular signaling. By hydrolyzing these cyclic nucleotides, PDE regulates their levels within the cell, thereby influencing various physiological responses, including those triggered by hormones.

cAMP Second Messenger System

The cAMP second messenger system is a critical signaling pathway in cells that transmits hormonal signals. When a hormone binds to its receptor, it activates adenylate cyclase, which converts ATP to cAMP. This increase in cAMP activates protein kinase A (PKA), leading to various cellular responses, such as changes in gene expression or metabolic activity.

Hormonal Stimulation

Hormonal stimulation refers to the process by which hormones bind to specific receptors on target cells, initiating a cascade of biochemical events. This can lead to the activation of second messenger systems like cAMP, resulting in physiological changes. The effectiveness of this signaling can be significantly altered by the activity of enzymes like PDE, which modulate the levels of second messengers.