The specificity of transmission in signaling pathways, for example, in cancer, is provided by mutations in proteins and genes, selective activation or sequencing of a specific protein, for example, p53, both at the level of genes (overexpression, inhibition), mRNA (splicing), protein translation (post-translational changes ).

Cornelius Krasel, thank you for your answer.

I suspected it would have something to do with spatial differentiation.

Dear Sam,

The answer to your question worths a Nobel prize :-) In my opinion, this is one of the very important open questions in biology. You very clearly described the core of the problem: there can be dozens of thousand cellular outcomes as responses to several dozens of thousand extracellular/environmental stimuli - transmitted by a few second messengers. Certainly, there might be several different mechanisms in maintaining specificity. Compartmentalization and other ways of localized production of second messengers very likely contribute, but I think these classic biological processes are, by far, not enough. The missing information might be encoded into the spatio-temporal dynamics of second messenger levels, or other, as yet not identified biophysical/biochemical features of the complex interaction network in cellular signaling. So, there must be a lot to discover :-)

Cheers, Karoly

Thanks Karoly,

This question will probably continue to bug me, until someone cleverer than me works it out! My own research interests lie more towards clinical research, but who knows where I may end up!

Like you said, it seems like a question that's pretty fundamental to cellular biology, it seems very much to get glossed over by lecturers I've spoken to about it.

Sam