cyaA

Bifunctional hemolysin/adenylate cyclase is a protein that in B. pertussis (the bacteria that causes whooping cough) is encoded by the cyaA gene. This protein in turn is cleaved into a calmodulin-sensitive adenylate cyclase (cyaA–ACD) and hemolysin. Both are virulence factors facilitating respiratory tract colonization by B. pertussis. The cyaA–ACD binds to a M2 integrin cell surface receptor and inserts its N-terminal adenylyl cyclase domain into the cytosol. After binding to calmodulin, cyaA–ACD catalyzes the cyclization of AMP into cAMP. This catalysis raises the intracellular concentration of cAMP to toxic levels.