Functional role of secreted chaperonins in the establishment of intracellular bacteria

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The study of microbes that live inside cells is central to understanding how persistent and chronic infections came to exist. How a microorganism that lives in the environment first acquires the ability to take residence in our own very cells? Ongoing investigations suggest that some environmental bacteria acquire this ability in response to the frequent encounters with voracious amoebas and other protozoa that are constantly feeding on bacteria. One of these bacteria is Legionella pneumophila (Lp), which accidentaly infects the lungs of humans that inhale contaminated water droplets produced in air conditioners, showers, etc. So, the question remains as to how Lp was able to leap from protozoa to humans? Lp, best known through the media coverage of Legionnaires' disease outbreaks, is a parasite that first learned to live inside amoeba. Therefore, Lp constitutes a very attractive model organism to study the adaptation of relatively primitive molecules to survive amoebal attacks, and make it all the way into the more complex human cells. My research focuses on one of these primitive (ancestral) molecules, the protein known as Hsp60 chaperonin. We know that Hsp60 is important and very old because it is present in all cellular life forms, and cells cannot live without it. I have shown that the Lp Hsp60 is a disease-causing factor that helps Lp get into cells, and then alters fundamental cellular processes like the organization of the cell's skeleton and the intracellular movement of organelles. To fulfill this mission the chaperonin needs to get outside from Lp and reach amoeba or the human cells, so I am also investigating how Lp secretes this protein. In my research, I will apply traditional microbiological techniques, light and electron microscopy, as well as genetic tools. The knowledge acquired studying the Lp Hsp60 chaperonin could help us to (i) better understand how other (perhaps more dangerous) microbes that live inside our cells cause disease, (ii) prevent the diseases caused by these microbes, and (iii) provide a safer water supply, lowering the risk of disease transmission.