Signaling pathways in all organisms consist of series of phosphorylation and dephosphorylation events that define directionality and allow different levels of feedback-regulation. Mass spectrometry-based proteomic analyses in recent years have led to a proteome-wide identification of thousands of phosphorylation sites in various plant species. Given this magnitude of mostly qualitative information about protein phosphorylation, discovery of specific phosphoproteins with regulatory functions represents a major challenge. In future large-scale experiments, combinations of data-driven modeling strategies based on quantitative data, targeted kinase-substrate screens, and verification in biochemical and genetic experiments are required to specifically spot phosphorylation sites with specific roles in signaling pathway modulation.
Copyright 2010 Elsevier Ltd. All rights reserved.