HUNGRY FOR PROTEIN: Colored scanning electron micrograph (SEM) of a group of Legionella pneumophila bacteria. CDC PUBLIC HEALTH IMAGE LIBRARY
C.T.D. Price et al., "Host proteasomal degradation generates amino acids essential for intracellular bacterial growth," Science, 334:1553-57, 2011.
When University of Louisville's Yousef Abu Kwaik and colleagues stumbled upon a eukaryotic protein in Legionella bacteria, he suspected the prokaryotes had stolen the gene from its host to help it co-opt their eukaryotic prey–either an amoeba or a human cell. Their investigations revealed that the protein, called AnkB, forces the host cell to degrade its own proteins into amino acids to provide sufficient quantities of nourishment for the parasitic bacterium.
The protein AnkB was known to tag perfectly healthy proteins with ubiquitin–an address label that marks misfolded proteins for proteasomal degradation–but it was unclear how this process benefited the bacterium. And, although bacteria are known to ...
