Genomic analysis of MAP kinase cascades in Arabidopsis defense responses

The process of phosphorylation and dephosphorylation is a common mechanism of signal transduction in plants, connecting the perception of extracellular signals with the final responses to those signals. This paper will concentrate on the mitogen-activated protein (MAP) kinase pathway, one of the main phosphorylation pathways that plants use in biotic and abiotic stress resistance. It is a cascade consisting of several classes of kinases, each having a different role in signal integration and divergence. The cascade is regulated by various mechanisms, including not only transcriptional and translational regulations but also post-transcriptional regulations and protein-protein interactions. Recent detailed analysis of certain specific MAP kinase pathways has revealed the specificity of the kinases in the cascade, signal transduction patterns, identity of pathway targets, and the complexity of the cascade. Strategies in the study of phosphorylation pathways are discussed, and approaches integrating various genomics and proteomics technologies are suggested.