Mediates lipid mixing of vesicles and full mixing of their contents in the absence and presence of GTP. Tethers and mixes small vesicles better than larger ones, indicating a curvature preference. GTP slows down DynA-mediated lipid fusion, perhaps controlling its activity. Prefers phospholipid composition close to the B.subtilis membrane; requires phosphatidylglycerol for fusion has no activity on pure phosphatidylethanolamine vesicles (PubMed:31361971). Regulates membrane lipid diffusion. Required to prevent membrane damage when exposed to low levels of membrane-damaging antibiotics or to bacteriophage. Probably surveys the cell membrane for stress; localizes to sites of membrane damage (treatment with nisin) and forms foci in cells treated with pore-forming compounds (CCCP). May assist membrane repair, possibly by membrane tethering and fusion (PubMed:26530236). Probably functions both in early and late cell division, affects the proper formation of the FtsZ ring. Plays a non-redundant role with flottilin (floT) in membrane dynamics and cell shape. Probably able to bend membranes (PubMed:23249255). Tethers liposomes and mediates their fusion; this does not require GTPase activity or the presence of GTP. Both GTPase domains (dynamin-type G) are required for GTPase activity (PubMed:21205012). Has intrinsic affinity for membranes and membrane distortion capability; causes tubulation and membrane distortion when expressed in a Drosophila cell line. GTP + H2O = GDP + H(+) + phosphate Requires Mg(2+) for membrane fusion. Homodimer in solution (Probable). Both D1 and D2 domains interact with YwpG, YneK interacts only with D1 while RNase Y (rny) only interacts with whole protein (PubMed:23060960). Probably oligomerizes at damaged membrane sites (Probable). Found at the division septum; in the absence of minJ dispersed along membrane. Associates with the cell membrane via the D1 domain, D2 does not associate with membranes (PubMed:21205012, PubMed:23060960). In growing cells forms foci at midcell, colocalizes with FtsZ. Membrane localized in non-growing cells (PubMed:23249255). Localized uniformly along cell membrane where it is highly dynamic, DynA localizes to regions of membrane deformation upon nisin treatment and remains at those sites. Localizes into foci upon membrane potential dissipation (CCCP treatment, forms membrane pores) (PubMed:26530236). Has 2 similar domains, D1 (approximately residues 1-600) and D2 (approximately residues 601-1193). D1 is able to bind membranes, tether liposomes and cause membrane fusion in the absence of D2; both regions are required for GTPase activity. Possibly the fusion of 2 dynamin-like genes (PubMed:21205012). D1 alone promotes membrane tethering but requires D2 for stable tethering and content mixing (PubMed:31361971). No visible phenotype (PubMed:21205012). 5% of cells have a double septa, 2% of cells are very long. Double dynA-ezrA mutants have longer cells with more double septa than either deletion alone. Double dynA-floT deletions are highly elongated, filamentous and have strong defects in cell shape; cells grow very slowly with an extended lag phase. Double dynA-mreB deletions have strong cell shape defects (PubMed:23249255). Double dynA-floT deletions are less motile than single floT deletions (PubMed:26842743). Increased lipid mobility in the cell membrane. Severe decrease in growth on nisin (causes membrane pore formation) with significant membrane deformation and damage, intermediate decrease in growth on antibiotics acting on lipid II or the membrane (bacitracin and daptomycin). No effect on growth on vancomycin (blocks peptidoglycan cross-links) or gramicidin D (makes small pores). 20-50% increased susceptibility to phage phi29 and SPbeta (PubMed:26530236). Strain PSB025 / 25152 does not have the SP-beta prophage. Belongs to the TRAFAC class dynamin-like GTPase superfamily. Dynamin/Fzo/YdjA family.