Oligomerization and kinetic mechanism of the dynamin GTPase.

Dynamin is a large molecular weight GTPase. Amongst other biological processes, it is involved in clathrin-dependent endocytosis. It can self-assemble or assemble on other macromolecular structures that result in an increase in its GTPase activity. Its role in endocytosis has been variously attributed to being a force-generating enzyme or a signalling protein. Here we review evidence for the oligomeric state of dynamin at high and low ionic strength conditions. We also review work on the elementary processes of the dynamin GTPase at high ionic strength and compare these to the ATPase of the force-generating protein myosin and the GTPase of the signalling protein Ras. New data on the interaction of dynamin with a fluorescent derivative of GTPgammaS are also presented. The possible mechanism by which assembly of dynamin leads to an increase in its GTPase activity is discussed.