Dynamin, a 100-kD GTPase first found in animal cells, is essential for vesicle formation in receptor-mediated endocytosis, synaptic vesicle recycling, and possibly vesicle trafficking in and out of the Golgi apparatus. Recently, dynamin-like proteins were also found in some plant cells. We demonstrate here the presence of dynamin with molecular weight of 100 kD in day-lily ( Hemerocallis fulva) pollen based on molecular estimation and Western blotting. The highly purified pollen Dynamin had GTPase activity, which could be stimulated 1.64 fold by calf brain microtubules in vitro. The results from electron microscopic examination showed that the pollen dynamin readily self-assembled into ring-like structures.
