Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 6/1/2011
Publication Date: 1/1/2012
Citation: Clouse, S.D., Goshe, M.B., Huber, S.C. 2012. Phosphorylation and RLK signaling. In: Kemmerling, B., Tax, F., editors. Receptor-Like Kinases in Plants: From Signaling to Development. Berlin Heidelberg, Germany: Springer-Verlag. p. 222-252. Interpretive Summary: Plant receptor kinases transmit extracellular signals to the interior of the cell via signal transduction cascades that control processes ranging from plant development to responses to the environment. Hence understanding how receptor kinases function is of fundamental importance. It is known that plant receptor kinases are regulated by protein phosphorylation of serine and threonine residues and recent evidence indicates that tyrosine residues can also be phosphorylated. However, while many sites of phosphorylation have been identified, little is known about stoichiometries and functional roles in vivo. In the two cases studied to date, tyrosine phosphorylation appears to be particularly important for receptor kinase function but recent surveys suggest that tyrosine phosphorylation may play a broad role in plant receptor kinase function. Because receptor kinases control key pathways associated with growth and development and responses to abiotic and biotic stress, knowledge of molecular mechanisms controlling their activities may yield new strategies to develop crops with improved biotic and abiotic stress tolerance.
Technical Abstract: Plant genomes encode hundreds of receptor-like kinases (RLKs) with an organization of functional domains similar to that of animal receptor kinases. Ligand-dependent phosphorylation has now been demonstrated for several plant RLKs and identification of specific phosphorylation sites followed by their functional characterization has advanced our understanding of RLK signaling mechanisms regulating growth, morphohogenesis, and disease resistance. Advances in mass spectrometry and phosphopeptide enrichment technology has been applied to plant phosphoproteomics, revealing hundreds of novel in vivo RLK phosphorylation sites and allowing comparative analysis of phosphorylation site sequence motifs. This chapter will examine recent studies on both targeted RLK phosphorylation site analysis as well as global phosphoproteomic studies that have generated data useful for understanding mechanisms of RLK phosphorylation and its role in plant signal transduction.