Dynamin Undergoes a GTP-Dependent Conformational Change Causing Vesiculation

Abstract

The dynamin family of GTPases is essential for receptor-mediated endocytosis and synaptic vesicle recycling, and it has recently been shown to play a role in vesicle formation from the trans-Golgi network. Dynamin is believed to assemble around the necks of clathrin-coated pits and assist in pinching vesicles from the plasma membrane. This role would make dynamin unique among GTPases in its ability to act as a mechanochemical enzyme. Data presented here demonstrate that purified recombinant dynamin binds to a lipid bilayer in a regular pattern to form helical tubes that constrict and vesiculate upon GTP addition. This suggests that dynamin alone is sufficient for the formation of constricted necks of coated pits and supports the hypothesis that dynamin is the force-generating molecule responsible for membrane fission.

Chapter 13 Visualization of Dynamins

“…Upon addition of GTP (1 mM final), all but the GalCer tubes constrict and under certain conditions fragment ( Fig. 3E-G) (Danino et al, 2004;Sweitzer and Hinshaw, 1998).…”

“…Dynamin interacts with lipid in vitro with a specific preference for negatively charged bilayers (Sweitzer and Hinshaw, 1998;Zheng et al, 1996). To generate dynamin oligomers on lipid bilayers, dynamin is incubated with liposomes for 1-2 h at room temperature.…”

“…Cryo-EM has also been used to visualize dynamin structures in their native states (Chen et al, 2004;Danino et al, 2004;Sweitzer and Hinshaw, 1998;Zhang and Hinshaw, 2001). Vitreous samples of dynamin-lipid tubes can be generated as described earlier.…”

SH3 Binding Domains in the Dopamine D4 Receptor

“…The GTPase mechanoprotein dynamin, that is important in pinching off the clathrin-coated vesicle fiom the membrane surface (Sweitzer and Hinshaw, 1998), contains several sites for SH3 binding (Scaife and Margolis, 1997). To date three dynamin genes have been isolated: one encoded for exclusively in neuronal tissues, the other found both in neuronai and testis or just in the periphery (Scaife and Margolis, 1997).…”

“…Recent reports suggest that the GTPase dynamin is essential for receptor-mediated endocytosis (Sweitzer and Hinshaw, 1998 Hébert and Bouvier, 1998). Visualization of some GPCRs separated on SDS-PAGE gel reveals molecular bands that correspond to the receptor as both monomers and dimers.…”