Probing the interaction between the Phytophthora infestans effector PexRD24 and the host enzyme Protein Phosphatase 1.
F. VARDEN (1), P. Birch (2), M. Banfield (1) (1) John Innes Centre, United Kingdom; (2) The James Hutton Institute, United Kingdom

The oomycete Phytophthora infestans infects a number of plant species – most infamously it is the causative agent of potato late blight. Like many other pathogens, P. infestans secretes effector proteins to promote pathogenesis, and these effectors have a wide range of activities. PexRD24 (also known as Pi04314) is a P. infestans RXLR-type effector that interacts with several isoforms of host Protein Phosphatase 1 (PP1). The catalytic subunit of PP1 (PP1c) can form complexes with numerous endogenous regulatory subunits that are responsible for modulating the subcellular localisation and substrate specificity of the enzyme. Recent studies suggest that PexRD24 mimics a regulatory subunit and relocalises PP1c from the host nucleolus to attenuate host defences and promote pathogen infection. We are taking a biochemical and structural approach to discover how the interaction between PexRD24 and PP1c alters the activity of PP1c to the advantage of the pathogen at the molecular level. Screening for protein production in E. coli revealed challenges regarding the solubility and stability of these proteins in vitro. However, we have shown that PexRD24 and PP1c form a complex in vitro, and enzyme assays are currently ongoing to address the effect of PexRD24 on PP1c. Ultimately, we aim to define the interaction between PexRD24 and PP1c at the protein structural level, to give clear insight into how the effector is manipulating its host target.

Abstract Number: P9-316
Session Type: Poster