Mapping phosphorylation pathways to discover host signaling events induced by Salmonella.

Responding and adapting to environmental changes is crucial to the survival of all living organisms, including cells. Cells use signaling cascades to detect stimuli in their environment and respond by altering the expression and turnover of specific genes and proteins. Since many signaling events are regulated by the addition of a phosphate to serine, threonine, or tyrosine residues on proteins within these cascades, identifying and characterizing these modifications is crucial to understanding how signalling pathways function. Until very recently, studying protein phosphorylation has been a slow and laborious process, as existing techniques limited researchers to studying only a few phosphsphorylation sites in isolation. However, the recent emergence of highly sensitive techniques in liquid chromatography-tandem mass spectrometry (LC-MS/MS), has enabled scientists to analyze thousands of phosphorylated proteins simultaneously. Lindsay Roger’s research utilizes LC-MS/MS to analyze thousands of protein phosphorylation events simultaneously in cells infected by Salmonella. Salmonella is an intracellular bacterial pathogen which, in humans, causes gastroenteritis and typhoid fever and is one of the most common and widely distributed food borne illnesses. During infection, Salmonella use a needle like complex to transport bacterial proteins, termed effectors, into host cells where they mimic host proteins and influence signalling. Currently, little is known about the host targets of the majority of Salmonella effectors and how they cause disease. Using these LC-MS/MS experiments, Ms. Rogers’s research is identifying a myriad of novel host targets of these proteins. It is expected that this research will provide a considerable leap in our understanding of how Salmonella infects its host.