Second messengers like cAMP (cyclic Adenosine Monophosphate) play an important role in cell signaling — they help carry the message from outside the cell to the inside so the cell can respond properly.
Here’s how it works, explained:
1. Signal received at the cell surface
A hormone or signal molecule (the first messenger) binds to a receptor on the cell membrane.
Example: adrenaline binding to its receptor.
2. Activation of an enzyme
The activated receptor triggers an enzyme called adenylate cyclase (found in the cell membrane).
This enzyme converts ATP into cAMP, which becomes the second messenger.
3. cAMP carries the message inside the cell
cAMP spreads the signal inside the cell and activates other proteins, such as protein kinase A (PKA).
These proteins then cause changes inside the cell — for example:
- Turning genes on or off
- Breaking down glycogen into glucose
- Changing enzyme activity
4. Response and control
Once the job is done, cAMP is broken down by an enzyme called phosphodiesterase to stop the signal, preventing overreaction.
In short:
cAMP acts as a second messenger that carries signals from the cell surface to the inside, helping the cell respond quickly to hormones and other signals.