Structural Basis of Host Autophagy-related Protein 8 (ATG8) Binding by the Irish Potato Famine Pathogen Effector Protein PexRD54

• Published in: The Journal of biological chemistry Vol. 291; no. 38; pp. 20270 - 20282
• Main Authors: Maqbool, Abbas, Hughes, Richard K., Dagdas, Yasin F., Tregidgo, Nicholas, Zess, Erin, Belhaj, Khaoula, Round, Adam, Bozkurt, Tolga O., Kamoun, Sophien, Banfield, Mark J.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 16-09-2016; American Society for Biochemistry and Molecular Biology
• Subjects: autophagy; Autophagy-Related Protein 8 Family - chemistry; Autophagy-Related Protein 8 Family - genetics; Autophagy-Related Protein 8 Family - metabolism; Crystallography, X-Ray; effector protein; host-pathogen interaction; Papers of the Week; Phytophthora infestans - chemistry; Phytophthora infestans - genetics; Phytophthora infestans - metabolism; Plant Diseases; plant molecular biology; plant pathogen; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Protein Domains; protein structure; Protein Structure, Quaternary; protein-protein interaction; Solanum tuberosum - chemistry; Solanum tuberosum - genetics; Solanum tuberosum - metabolism; host-pathogen interaction; protein structure; plant molecular biology; autophagy; plant pathogen; protein-protein interaction; effector protein
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M116.744995

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.