The cell signaling pathway consists of 3 stages: 

• Reception – This is the first stage of the cell signaling pathway. During this stage, a signaling molecule binds to a receptor protein located on the surface of the cell or inside the cell. 
• Signal Transduction – On binding with the signaling molecule, the receptor protein undergoes a conformational change, which triggers a series of enzyme activations that initiates the process of transduction. The signal transduction stage involves multiple steps in which each relay molecule in the signal transduction pathway triggers changes in the next molecule along the pathway. 
• Response – In this final stage of the cell signaling pathway, the signal elicits a specific cellular response.