Additional data from our 2010 publication

Back to EPEC lab Page

The EspF effector and the host nucleolus

The nucleolus is a eukaryotic structure with the cell nucleus that is primarily responsible for ribosome biogenesis. A feature common to almost all viruses is that they target their viral proteins to the nucleolus, although it is not clear why they do this. Our lab has recently shown that the EPEC effector EspF targets the nucleolus (PLOS Pathogens publication) and this leads to nucleolar alterations. EspF is the first bacterial protein known to target the nucleolus during bacterial infection. In the same study, we also show that the host’s mitochondria kinetically regulate when EspF is able to target the nucleolus. This is a neat mechanism as the bacterial pathogen exploits a host organelle to control the functions of its effector proteins. Whether viruses utilize this mechanism remains to be seen but a number of viral proteins are known to target both the mitochondria and nucleolus, like EspF.

Here are some images and videos relating to this project:

EspF in the nucleolus of host cells transfected with pEGFP-EspF (the L16E variant).

espfgfp

EspF(L16E)
espfgfptemplate2

Host cell

Series008Snapshot1-copy

EspF in the nucleolus of host cells transfected with pEGFP-EspF (native EspF).

Notice the targeting of both the mitochondria and the nucleolus
espf nucleolus

EspF = Green; DNA = Red

EspF in infected host nucleoli

Deconvolved confocal image of a host cell infected with EPEC encoding an EspF variant that does not target the mitochondria

This variant of EspF rapidly fills the host nucleolus
pl16e1 400dpi
hela l16e images_Snapshot_10

EspF(L16E) does not target mitochondria but rapidly targets the nucleolus

EspF = Green

DNA = Blue
single gif

EspF in the nucleolus of HeLa cells
optimised gif

Intracellular Salmonella typhimurium (aqua) recruits the nucleolar protein nucleolin (yellow)
sal400dpi

In our recent publication, we show that the bacterial pathogen Salmonella typhimurium causes the mobilisation of nucleolar nucleolin (yellow) from the nucleolus into the cytoplasm where it is sequestered around the intracellular bacteria (Aqua)

Back to EPEC lab Page