New actor in plant immune signaling
Plants can perceive in their environment generic pathogen patterns through transmembrane receptors. For instance the bacterial flagellin is recognized by the complex FLS2-BAK1. This event triggers an intracellular signaling which includes the activation of the cytoplasmic kinase BIK1 required for the production of reactive oxygen species.
In a recent article published in EMBO reports (Jiang et al., 2019), a collaborative work between the teams of Heribert Hirt (KAUST, Saudi Arabia) and Jean Colcombet (IPS2) revealed that the kinase MAP4K4, an homologue of the yeast Ste20 protein, plays a dual role in the activation of BIK1. First MAP4K4 directly phosphorylates BIK1, thereby increasing its stability. Secondly MAP4K4 also phosphorylates PP2C38, the phosphatase which inhibits BIK1, to promote its dissociation and reinforce BIK1 activation. Overall these results enlarge our understanding of early plant immune signaling. They also shed new light on the roles of the multigenic MAP4K family in plants.
Contact: jean.colcombet @ inra.fr
Link to the article: https://www.embopress.org/doi/abs/10.15252/embr.201947965