Protein droplets inside cells can change membrane voltage on contact
Scripps Research biophysicists report that charged biomolecular condensates, droplet-like assemblies of proteins and RNA, shift the voltage of model membranes where they touch, by amounts the team likens to nerve-impulse scale.
What happened
Using giant unilamellar vesicles, which are simple artificial cell membranes, the team showed that charged condensates landing on a membrane changed its voltage at the point of contact. Condensates carrying more charge had bigger effects, and the shape the droplet took against the membrane correlated with how much the voltage changed. The press release says some changes were "on the same scale as voltage changes in nerve impulses", though it gives no exact values.
Why it matters
Membrane voltage is usually explained by ion channels and pumps. This study suggests a separate mechanism, in which the cell's internal condensates act like small local batteries. If confirmed in living cells, it would add a new layer to how cells control electrical signals locally.
Caveats
The experiments used artificial vesicles, not living cells, and whether condensates change membrane potential this way inside cells is still unknown.