Figure 3.

Stimulation of dynamin GTPase activity by amphiphysin 1. Dynamin (0.2 μM) and increasing amount of amphiphysin 1 were incubated either with 2 μg of large unilamellar liposomes (A) or with 2 μg of sonicated small liposomes (B), in the presence of 1 mM GTP containing [γ-³²P]GTP (0.8 μCi). After incubation, ³²P_i released from the radiolabeled GTP was measured. Data represent the mean value of triplicate measurements. (C) GTPase activity assayed using extruded small liposomes. (D) Recruitment of dynamin to large unilamellar liposomes (left two lanes) or to sonicated small liposomes (right two lanes) in the presence or absence of amphiphysin 1. Results shown are the average of three assays±s.d.