Cyclic adenosine monophosphate (cAMP) is a second messenger that helps to transmit signals within cells. It's made from adenosine triphosphate (ATP) by enzymes called g-proteins that are attached to metabotropic receptors. When these receptors are activated, the g-proteins release cAMP. This release then triggers a chain of events that leads to various cellular responses.
Here's a breakdown:
- Second messenger: cAMP is not the initial signal, but rather a signal that relays information from outside the cell to the inside.
- Metabotropic receptors: These receptors are activated by signaling molecules like hormones and neurotransmitters.
- G-proteins: These are a family of proteins that bind to metabotropic receptors. When a receptor is activated, the g-protein releases cAMP.
- Cellular responses: cAMP plays a crucial role in many biological processes, including:
- Cell growth and differentiation
- Metabolism
- Hormone regulation
- Nervous system function
For example, when adrenaline binds to its receptor on a heart muscle cell, it activates a g-protein which releases cAMP. This cAMP then activates an enzyme called protein kinase A (PKA). PKA then goes on to phosphorylate other proteins within the cell, ultimately leading to an increase in heart rate.
In summary, cAMP is a vital molecule that acts as a second messenger in cells, playing a crucial role in various biological processes. Its widespread function makes it a target for drug development in a variety of diseases.
