Catalyzes the formation of the second messenger cAMP from ATP. Its transcript is probably degraded by endoribonuclease LS (rnlA), decreasing cAMP levels and the negative regulator Crp-cAMP, which then induces its own transcription again. ATP = 3',5'-cyclic AMP + diphosphate The regulatory domain is involved in the regulation of cyclase activity by the carbon source. Activated by the PTS system, glucose-specific IIA component (CRR). Repressed by the Crp-cAMP complex. Expression increases during growth, decreasing again in stationary phase; more strongly induced in an rnlA deletion mutant, levels remain high even in stationary phase (at protein level). Not essential, eliminates the NaCl sensitivity of an rnlA deletion mutant. Belongs to the adenylyl cyclase class-1 family.