Pl. Tuma et al., ACTIVATION OF DYNAMIN GTPASE BY ACIDIC PHOSPHOLIPIDS AND ENDOGENOUS RAT-BRAIN VESICLES, The Journal of biological chemistry, 268(23), 1993, pp. 17240-17246
Dynamin is a GTPase thought to play a role in endocytosis based on gen
etic analysis of its homolog in Drosophila melanogaster shibire. Previ
ous studies have stressed an in vitro association with microtubules, t
hough additional evidence suggests that dynamin associates with membra
nous organelles. In an analysis of the enzymatic and membrane binding
properties of dynamin, we have found that the acidic phospholipids, ph
osphatidylserine, phosphatidylglycerol, and phosphatidylinositol, are
able to stimulate GTP hydrolysis in a manner similar to activation pre
viously shown with microtubules. A neutral phospholipid, phosphatidylc
holine, had no effect on dynamin GTPase. Activation of dynamin was bip
hasic, with a decrease in activity back to basal levels with increased
concentrations of either microtubules or liposomes. A comparison betw
een GTPase stimulation induced by microtubules and that by phospholipi
ds suggests that ionic interactions between the basic C-terminal domai
n of dynamin and the negatively charged microtubule or phospholipid he
ad group are important. In support of this, GTPase stimulation by thes
e agents in combination was not additive. A salt-extracted membrane fr
action from brain tissue also activated dynamin GTPase, though to a lo
wer extent than pure phospholipids. These results suggest that membran
e components could be responsible for some aspects of the regulation o
f dynamin function in vivo.