noun, plural: effectors
In biochemistry, an effector is that molecule that binds to a specific protein, and regulates the latter's biological activity. An effector molecule acts as a ligand that is capable of increasing or decreasing the activity of that protein. It can also regulate the activity of certain mRNA molecules (e.g. riboswitches), gene expression, and cell signaling. The main types of effectors are the activators and the inhibitors. Examples of effectors are as follows: (1) allosteric effectors, (2) bacterial effectors, and (3) fungal effectors (e.g. apoplastic effectors and cytoplasmic effectors).