pH-sensing collaboration with the Childers lab out in Nature Communications

Our collaboration with the Childers lab (University of Pittsburgh) and the Schrader lab (Indiana University) is out in Nature Communications! The study shows that bacterial ribonucleoprotein bodies (BR-bodies) — membraneless condensates that carry out RNA decay — maintain an acidic internal pH that tunes the enzymes inside them. In other words, bacteria can build a chemically distinct, organelle-like compartment without a membrane.

We changed how the field pictures the inside of a condensate. By reading the fluorescence lifetime of a pH-sensitive reporter (RNase E–pHluorin2) alongside single-molecule localization microscopy, we showed that a single BR-body is not a uniform droplet at all: it contains coexisting, nanoscale acidic sub-domains with sharp internal pH gradients. Paired with a multidimensional analysis of these lifetime maps, this moves condensates from the picture of a well-mixed liquid droplet to spatially heterogeneous chemical networks, where the local chemistry — not the average composition — decides what the enzymes inside actually do.

Congratulations to Moeka Sasazawa and Ryan Cho, and to our collaborators in the Childers and Schrader labs!