Comparison of Salmonella and Shigella host cell invasion. Salmonella are targeted by the host E3 ligase RNF213, which ubiquitylates bacterial lipopolysaccharide (LPS), marking bacteria for autophagic destruction. Shigella employs its effector proteins IpaH1.4 - an E3 ubiquitin ligase itself - to ubiquitylate RNF213, leading to its proteasomal degradation and thus preventing the host from tagging Shigella for destruction.
Cryo-EM structure showing how the leucine-rich repeat (LRR) domain of IpaH1.4 binds to the RING domain of RNF213
How do cytosol-invading bacteria evade LPS ubiquitylation by the host's defence machinery?
@felixrandow.bsky.social's group determined that Shigella flexneri uses IpaH1.4 to degrade the LPS ligase RNF213, inhibiting the cell's ubiquitylation abilities.
Read more: tinyurl.com/3y4kv2bp
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