title: Structural analysis of Pseudomonas syringae AvrPtoB bound to host BAK1 reveals two similar kinase-interacting domains in a type III Effector.
abstract: To infect plants, Pseudomonas syringae pv. tomato delivers ~30 type III effector proteins into host cells, many of which interfere with PAMP-triggered immunity (PTI). One effector, AvrPtoB, suppresses PTI using a central domain to bind host BAK1, a kinase that acts with several pattern recognition receptors to activate defense signaling. A second AvrPtoB domain binds and suppresses the PTI-associated kinase Bti9 but is conversely recognized by the protein kinase Pto to activate effector-triggered immunity. We report the crystal structure of the AvrPtoB-BAK1 complex, which revealed structural similarity between these two AvrPtoB domains, suggesting that they arose by intragenic duplication. The BAK1 kinase domain is structurally similar to Pto, and a conserved region within both BAK1 and Pto interacts with AvrPtoB. BAK1 kinase activity is inhibited by AvrPtoB, and mutations at the interaction interface disrupt AvrPtoB virulence activity. These results shed light on a structural mechanism underlying host-pathogen coevolution.
authors.affiliation: Key Laboratory for Protein Sciences of Ministry of Education, School of Biological Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Cheng
authors.forename: Kathy R
authors.initials: KR
authors.lastname: Munkvold
authors.forename: Haishan
authors.initials: H
authors.lastname: Gao
authors.forename: Johannes
authors.initials: J
authors.lastname: Mathieu
authors.forename: Simon
authors.initials: S
authors.lastname: Schwizer
authors.forename: Sha
authors.initials: S
authors.lastname: Wang
authors.forename: Yong-bin
authors.initials: YB
authors.lastname: Yan
authors.forename: Jinjing
authors.initials: J
authors.lastname: Wang
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Martin
authors.forename: Jijie
authors.initials: J
authors.lastname: Chai
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000737:chemistry / Q000201:enzymology* / Q000382:microbiology; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000382:microbiology*; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D044224:Pseudomonas syringae / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D010940:Plant Proteins; C081695:avrPto protein, Pseudomonas syringae; D017346:Protein Serine-Threonine Kinases