A bacterial inhibitor of host programmed cell death defenses is an E3 ubiquitin ligase

作者：Janjusevic R; Abramovitch RB; Martin GB^*; Stebbins CE

来源：Science, 2006, 311(5758): 222-226.

DOI：10.1126/science.1120131

The Pseudomonas syringae protein AvrPtoB is translocated into plant cells, where it inhibits immunity-associated programmed cell. death (PCD). The structure of a C-terminal domain of AvrPtoB that is essential for anti-PCD activity reveals an unexpected homology to the U-box and RING-finger components of eukaryotic E3 ubiquitin ligases, and we show that AvrPtoB has ubiquitin ligase activity. Mutation of conserved residues involved in the binding of E2 ubiquitin-conjugating enzymes abolishes this activity in vitro, as well as anti-PCD activity in tomato leaves, which dramatically decreases virulence. These results show that Pseudomonas syringae uses a mimic of host E3 ubiquitin ligases to inactivate plant defenses.

• 出版日期2006-1-13