The heterotetrameric DLP1(2)-DLP2(2) complex tethers liposomes and may mediate their fusion. Initial binding is probably mediated by DLP1, while DLP2 couples DLP1 subunits and increases the effective reach of the complex up to 45 nm. The role of the nucleotide is unknown. This subunit alone very weakly binds to liposomes; GTP, GDP, GMPPCP and GMPPNP do not change heterotetramer binding. Tetramerization is required for GTPase activity, suggesting the GTPase domains (dynamin-type G) from DLP1 and DLP2 must dimerize to reconstitute the GTPase active site. GTP + H2O = GDP + H(+) + phosphate Forms a 2:2 heterotetramer with DLP1. DLP2 forms a central back-to-back dimer flanked on each side by a DLP1 subunit. In the crystal structures the 2 DLP1 subunits are in very different conformations. The 9 residue linker permits DLP1 (tethered to DLP2) considerable flexibility; it is long enough to allow the GTPase domains (dynamin-type G) of DLP1 and DLP2 to heterodimerize. Two regions within the tip of the trunk are required for homodimerization; deletion of residues 348-401 and 509-542 prevents DLP2 dimerization, but not formation of a DLP1-DLP2 dimer. Double dlp1-dlp2 deletions have no obvious cell division defects, have no flagella (possibly due to loss of expression of flgP) and are non-motile. Belongs to the TRAFAC class dynamin-like GTPase superfamily. Dynamin/Fzo/YdjA family. Truncated N-terminus.