Drp1 is a dynamin-like GTPase that mediates mitochondrial and peroxisomal 
division in a process dependent on self-assembly and coupled to GTP hydrolysis. 
Despite the link between Drp1 malfunction and human disease, the molecular 
details of its membrane activity remain poorly understood. Here we reconstituted 
and directly visualized Drp1 activity in giant unilamellar vesicles. We 
quantified the effect of lipid composition and GTP on membrane binding and 
remodeling activity by fluorescence confocal microscopy and flow cytometry. In 
contrast to other dynamin relatives, Drp1 bound to both curved and flat 
membranes even in the absence of nucleotides. We also found that Drp1 induced 
membrane tubulation that was stimulated by cardiolipin. Moreover, Drp1 promoted 
membrane tethering dependent on the intrinsic curvature of the membrane lipids 
and on GTP. Interestingly, Drp1 concentrated at membrane contact surfaces and, 
in the presence of GTP, formed discrete clusters on the vesicles. Our findings 
support a role of Drp1 not only in the formation of lipid tubes but also on the 
stabilization of tightly apposed membranes, which are intermediate states in the 
process of mitochondrial fission.