You say "effector", I say "artifact" - how do we know a protein is truly secreted?
We've been thinking a lot lately about how our favorite endosymbiont Wolbachia manipulates host biology . Because Wolbachia are not genetically tractable - or even culturable outside of host cells - it's pretty difficult to figure out the mechanisms used by the bacterium. However, we can start with some assumption about our expectation: Wolbachia likely secrete proteins into the host cell and change cell biology to facilitate infection. This is not ground breaking or novel in any way - invading intracellular microbes must deal with the host during infection - and many do this via secretion of proteins, called " effectors ." We know that these effectors often contain eukaryotic domains and homologies because they interface with the eukaryotic cell - a completely different domain of life. But how do we identify the proteins secreted by Wolbachia, or any symbiont? There have been some pretty clever work arounds. For example, John Beckmann and Anne Fallon used mass spec