Sometimes you just have to rethink your old ideas. Take Hosni Mubarak, for instance: as recently as January, his long-term plan focused on staying put in his presidential palaces in Cairo. Today, he’s taking an extended holiday at the shore and has approximately zero chance of fulfilling his old political ambitions.
In science, researchers revisit their old ideas every day, and sometimes things require a re-write. Take the quorum sensing system in Pseudomonas aeruginosa, for instance. The quorum sensing signal receptor LasR senses acyl-homoserine lactone (acyl-HSL) and gets the ball rolling on a battery of genes involved in virulence of P. aeruginosa. For a while now, folks working on this system thought LasR was folded around acyl-HSL as the protein was synthesized and that the protein couldn’t fold correctly in the absence of the signal.
One of the studies published by mBio this week takes a closer look at these notions and presents evidence that this thinking was wrong. By depleting the signal molecule acyl-HSL in culture and monitoring the concentration in cells, they proved that LasR lets go of its acyl-HSL. When the quorum signaling molecule is added back, LasR takes the signal molecule back up and ramps up for virulence, proving that the protein can remain in a properly folded conformation that is capable of re-associating with the signal. Knowing that the signal for quorum sensing can be released and taken up again by the receptor protein and that new protein doesn’t need to be synthesized to carry out the quorum sensing process could change the thinking about therapies to inhibit quorum sensing in patients with P. aeruginosa infections.