Structural basis of host autophagy-related protein 8 (ATG8) binding by the Irish Potato Famine pathogen effector protein PexRD54

Abbas Maqbool, Richard K. Hughes, Yasin F. Dagdas, Nicholas Tregidgo, Erin Zess, Khaoula Belhaj, Adam Round, Tolga O. Bozkurt, Sophien Kamoun, Mark J. Banfield

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Filamentous plant pathogens deliver effector proteins to host cells to promote infection. The Phytophthora infestans RXLR-type effector PexRD54 binds potato ATG8 via its ATG8 family-interacting motif (AIM) and perturbs host-selective autophagy. However, the structural basis of this interaction remains unknown. Here, we define the crystal structure of PexRD54, which includes a modular architecture, including five tandem repeat domains, with the AIM sequence presented at the disordered C terminus. To determine the interface between PexRD54 and ATG8, we solved the crystal structure of potato ATG8CL in complex with a peptide comprising the effector's AIM sequence, and we established a model of the full-length PexRD54-ATG8CL complex using small angle x-ray scattering. Structure-informed deletion of the PexRD54 tandem domains reveals retention of ATG8CL binding in vitro and in planta. This study offers new insights into structure/function relationships of oomycete RXLR effectors and how these proteins engage with host cell targets to promote disease.
Original languageEnglish
Pages (from-to)20270-20282
Number of pages13
JournalJournal of Biological Chemistry
Issue number38
Early online date25 Jul 2016
Publication statusPublished - 16 Sep 2016


  • autophagy
  • host-pathogen interaction
  • plant molecular biology
  • protein structure
  • protein-protein interaction
  • effector protein
  • plant pathogen

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