Activation of GTPase of Drp1 by eEF2
Next, we determined and compared the effects of eEF2 and its deletion mutant (Fig. 6a ) on GTPase activity of Drp1, using the purified proteins in the in vitro GTPase assay. Fig. 6b shows that while wild-type eEF2 could substantially increase Drp1 GTPase activity in a concentration-dependent manner, the eEF2 mutant that lacks GTP binding motif had little stimulating effect on GTPase of Drp1. These results further support the role of eEF2-Drp1 interaction in promoting mitochondrial fission, which is driven by Drp1 through its GTPase activity (Fig. 6c ).