A receptor is a protein that is able to bind a signaling molecule, a so-called ligand. It is often compared with a key and a lock – the signaling molecule is the key, and when it reaches the receptor, the lock, it leads to an effect. In cell signaling, this effect is often a signaling cascade in the cell, leading to a response.
Sources:
- Khan Academy. Ligands & receptors. https://www.khanacademy.org/science/biology/cell-signaling/mechanisms-of-cell-signaling/a/signal-perception (accessed 8. August 2020)
- Tripathi A. et al. Molecular Docking: From Lock and Key to Combination Lock. J Mol Med Clin Appl. 2017; 2(1): 10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5764188/