The Three Stages of Cell Signaling

Just like how you communicate or talk with someone, the cells in your body use a simple yet sophisticated form of communication, which is vital to keep it healthy and functioning properly.  This communication process is called cell signaling.  We can break down this cycle into three stages: message reception, transduction, and response.Reception

This first stage in the cell signaling cycle is when a signal, which could be a hormone or chemical, also known as ligands, reaches a target cell and makes contact through one of its receptors.  These receptors are dotted all over the surface of the cell, and each one is designed to accept only specific ligands and nothing else.  For example, an epinephrine receptor will only accept a epinephrine signal.  Receptors are the gateways through which signals enter the cell and trigger the next step in the messaging process.

Cell Reception.jpg
This is a rough example of what the reception stage looks like.


Transduction is the second stage of cell signaling.  After a  receptor receives a specific hormone or chemical message it activates certain proteins within the cell, causing a very specific chemical change. It is important to understand that the original signal that was accepted by the the receptor in the first stage never entered the cell.  Rather, transduction refers to the series of desired chemical changes in the cell.  Transduction is complete when the cell is able to give the proper response.


This third and final step is the cell’s response.  There are hundreds of signaling molecules that can be produced by your body, and limitless ways for your cells to respond to those signals.  For instance, when a cell is old, infected, or in the early stages of embryonic growth, it can actually receive the signal to kill itself.  The signal, a caspase enzyme, is received and transduced, like normal, but then the cell responds to the message by self-destructing!  Cell signaling responses can range from breaking down molecules for energy, killing a cell or producing a ligand to go through the same cell signaling process!

An efficient system

As you read this, all of the cells in your body are receiving or are waiting to receive their next signal to direct their next action (and hopefully it is not the self-destruct one!). What is amazing is the three phases of the signaling cycle—reception, transduction, and response—occur very rapidly and can send a message to all the appropriate cells within a matter of seconds or less!

Much like the way we hear words or sounds, quickly interpret or translate their meaning, and then do some action as a result, such as say a reply, the cells within our bodies also communicate with each other.

Quinn Palmer


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