Why do MAPKs have a 3 tiered structure?

Does dual phosphorylation requirement of MAPKs for activation have an advantage?

Interesting question Kaushik, and very ‘specific’ that can probably be answered by your lecturer/tutor (assuming that you are a University student) or by an on-line search! As you likely know the MAPK pathway has been reasonably well-conserved across evolution. According to a recent computer simulation study (see - http://www.ncbi.nlm.nih.gov/pmc/articles/PMC41288) the 3-tiered module is both robust and adaptable (for “random mutations to generate phenotypic variation during evolution”). In terms of the tight control subserved by dual phosphorylation, the same article suggests that a distributive phosphorylation system is good at amplifying input signals (e.g., see also an article on activation mechanism of ERK2 by dual phosphorylation - http://www.cell.com/abstract/S0092-8674 … 980351-7).