Hello everyone, I’ve begun to write my thesis, and I wondered when should each of these terms - when discussing genetic/protein interactions or activity or response of the cell to a stimulus involving a specific gene - be used in a scientific discourse: moderate, modulate and mediate. I have some ideas about their use, but I’d like to know from those who have written papers/scientific monographs how these terms actually differ from one another. This will give me a clearer idea about them so I can use them in a consistent manner.
To some extent these overlap depending on where one places the emphasis which is probably why you’re asking about their use. This is particularly so for moderate and modulate. That said, here are my suggested uses;
moderate/moderator: generally refers to a situation where one molecule/pathway/process/cell controls the activity/action of another molecule/pathway/process/cell by restricting its action. For example, phosphorylation of the EGF receptor by protein kinase C reduces the affinty of this receptor for EGF and therefore moderates the growth stimulation effects of EGF. The key point here is that the role of the phosphorylation is to restrict a process where as protein kinase C can act both as a moderator and an activator (in other pathways).
modulate/modulation: generally refers to a situation one one molecule/process/pathway/cell controls the activity/action of another molecule/process/pathway/cell by regulating its activity. For example, Ras-related small GTPases and their downstream effectors are able to both positively or negatively control the ligand binding affinity of integrins. This example is similar to the role of protein linase C in the cell.
mediate/mediator: this is perhaps the easiest to explain and refers to a situation where one process/activity is effected (occurs through)/via/because of) another. A simple example here would be cell mediated immunity.
This makes very good sense. Textbooks and reviews do not explain these terms and students are usually for themselves to make a meaning of these simple but important terms. Your explanations and examples clarified many things and will help me immensely. Thank you very much!