Calcium-mediated cell communication predates complex life, bacteria show

Scientists discovered that multicellular bacteria use calcium signals to regulate intercellular connections similar to those in higher organisms. This suggests such communication mechanisms evolved much earlier than previously thought. The findings were published in The EMBO Journal.

The study focused on multicellular cyanobacteria, which coordinate intercellular communication through septum junctions—structures functionally analogous to the gap junctions found in eukaryotic cells. Researchers identified a calcium-binding protein (CSE) unique to these bacteria. Using NMR spectroscopy, they mapped its structure when bound to calcium and confirmed its role as a calcium buffer. Cryo-electron microscopy revealed that mutant cells lacking CSE displayed markedly fewer connecting structures, underscoring calcium's regulatory importance.

These findings, published in The EMBO Journal, emerged from collaboration between Heinrich Heine University Düsseldorf and the University of Tübingen. The discovery that prokaryotes already possessed calcium-regulated communication mechanisms suggests these fundamental processes originated far earlier in evolutionary history than previously assumed, potentially reshaping understanding of how complex multicellularity developed.