Bifunctional protein that catalyzes the synthesis of cyclic-di-GMP (c-di-GMP) in response to reductive stress and then dynamically relocates to the division site to arrest cell division in response to envelope stress. In the presence of high intracellular c-di-GMP levels, and in response to envelope stress, interacts with cell division proteins and halts cell division, without disassembling the Z ring, but by blocking its further progress toward cytokinesis (PubMed:27507823). Part of a network that regulates cell motility by altering levels of c-di-GMP (PubMed:20303158). 2 GTP = cyclic di-3',5'-guanylate + 2 diphosphate Binds 1 Mg(2+) ion per monomer. Inhibited by YfiR, which prevents relocation to the midcell. A reductive stress signal is required to inactivate YfiR and turn on the DGC activity of DgcN. Purine metabolism; 3',5'-cyclic di-GMP biosynthesis. Homodimer (Probable). Interacts with the cell division proteins FtsZ and ZipA (PubMed:27507823). Localizes to the midcell in a Z ring-dependent manner in response to cell envelope stress. Expressed at low levels at both 28 and 37 degrees Celsius during transition into stationary phase. Deletion of the gene increases swimming motility and early biofilm formation (PubMed:21181144). Disruption partially suppresses the reduced motility of a pdeH disruption; concomitant disruption of dosC, dgcE, dgcQ and dgcN completely restores motility, suggesting these 4 genes, together with the c-di-GMP phosphodiesterase PdeH, form a network that regulates cell motility by altering levels of c-di-GMP (PubMed:20303158).