NDP52, a novel autophagy receptor for ubiquitin-decorated cytosolic bacteria

N von Muhlinen, T Thurston, G Ryzhako, S Bloor… - Autophagy, 2010 - Taylor & Francis
N von Muhlinen, T Thurston, G Ryzhako, S Bloor, F Randow
Autophagy, 2010Taylor & Francis
Autophagy functions as a cell-autonomous effector mechanism of innate immunity by
separating bacteria from cytosolic resources and delivering them for lysosomal destruction.
How cytosolic bacteria are targeted for autophagy is incompletely understood. We recently
discovered that Salmonella enterica serotype Typhimurium and Streptococcus pyogenes
are detected by NDP52 (nuclear dot protein 52kDa), after these bacteria enter the cytosol of
human cells and become decorated with poly-ubiquitinated proteins. NDP52 binds the …
Autophagy functions as a cell-autonomous effector mechanism of innate immunity by separating bacteria from cytosolic resources and delivering them for lysosomal destruction. How cytosolic bacteria are targeted for autophagy is incompletely understood. We recently discovered that Salmonella enterica serotype Typhimurium and Streptococcus pyogenes are detected by NDP52 (nuclear dot protein 52kDa), after these bacteria enter the cytosol of human cells and become decorated with poly-ubiquitinated proteins. NDP52 binds the bacterial ubiquitin coat as well as ATG8/LC3 and delivers cytosolic bacteria into autophagosomes. In the absence of NDP52 ubiquitin-coated bacteria accumulate outside ATG8/LC3+ autophagosomes. Cells lacking NDP52 fail to restrict bacterial proliferation, as do cells depleted of TBK1, an IKK family kinase colocalizing with NDP52 at the bacterial surface. Our findings demonstrate the existence of a receptor for the selective autophagy of cytosolic bacteria, suggesting that cells are able to differentiate between anti-bacterial and other forms of autophagy.
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