Participates in a DNA-damage check-point. DisA forms globular foci that rapidly scan along the chromosomes searching for lesions. Has also diadenylate cyclase activity, catalyzing the condensation of 2 ATP molecules into cyclic di-AMP (c-di-AMP). c-di-AMP likely acts as a signaling molecule that may couple DNA integrity with a cellular process. 2 ATP = 3',3'-c-di-AMP + 2 diphosphate Diadenylate cyclase activity is inhibited by the interaction with RadA. Homooctamer (By similarity). Interacts with RadA; this interaction leads to the inhibition of the diadenylate cyclase activity of DisA. Forms part of an operon with radA. Overexpression of DisA leads to cell expansion, induces cell aggregation, and inhibits bacterial growth and motility; coexpression of RadA rescues these abnormal phenotypes. Belongs to the DisA family.