Second messenger system
Second Messenger System
The Second Messenger System is a method of cellular signal transduction. This system is characterized by the involvement of an intermediary molecule, or a "second messenger," in the process of communication between cells.
Pronunciation
Sec·ond Mes·sen·ger Sys·tem
Etymology
The term "Second Messenger System" is derived from the role of these intermediary molecules in cellular communication. They are termed "second messengers" because they relay the message from the first messenger (usually a hormone or neurotransmitter) to the target cell.
Definition
The Second Messenger System is a key component of cellular signal transduction, the process by which cells respond to external stimuli. In this system, a first messenger (an extracellular signaling molecule) binds to a specific receptor on the cell surface, triggering the production or release of a second messenger inside the cell. This second messenger then initiates a series of intracellular events, leading to the desired cellular response.
Types of Second Messengers
There are several types of second messengers, including cyclic adenosine monophosphate (cAMP), inositol trisphosphate (IP3), diacylglycerol (DAG), and calcium ions (Ca2+).
Role in Cellular Communication
The Second Messenger System plays a crucial role in cellular communication, allowing cells to respond to external stimuli. This system is involved in numerous physiological processes, including hormone regulation, immune response, and neural signaling.
Related Terms
- First Messenger: The extracellular signaling molecule that initiates the second messenger system.
- G Protein: A type of protein that acts as a molecular switch, turning on the second messenger system when activated by a first messenger.
- Signal Transduction: The process by which a cell converts one kind of signal or stimulus into another.
- Receptor (biochemistry): A protein molecule that receives and responds to a first messenger.
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