UC Santa Cruz

Vibrio cholerae biofilm formation is central to both pathogenicity and environmental persistence. The matrix proteins RbmA, Bap1, and RbmC along with Vibrio-exopolysaccharide (VPS) provide the foundation for biofilm architecture. Through genetic analysis and extracellular complementation assays, we demonstrate that Bap1 and RbmC both contain VCBS and Lectin domains that discretely contribute to biofilm formation. We determined that Bap1 and RbmC both interact with RbmA, providing an explanation for their functional redundancy. Further characterization of interactions of matrix components revealed that Bap1 but not RbmC can interact with VPS. We also analyzed posttranslational regulatory controls on matrix protein stability and found that HapA is the primary protease responsible for degradation of Bap1 and RbmC. To understand how matrix interactions impact protein stability, we identified that biofilm architectural components contribute to protease activity, indicating that structural integrity potentiates matrix proteolysis. These findings fill a crucial knowledge gap regarding biofilm formation and the subsequent degradation during Vibrio cholerae biofilm formation.