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Science. 2006 Jan 13;311(5758):222-6. Epub 2005 Dec 22.

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

Author information

1
Laboratory of Structural Microbiology, Rockefeller University, New York, NY 10021, USA.

Abstract

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.

PMID:
16373536
DOI:
10.1126/science.1120131
[Indexed for MEDLINE]
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