A new dynamin-like protein, ADL6, is involved in trafficking from the trans-Golgi network to the central vacuole in Arabidopsis

Dynamin, a high-molecular-weight GTPase, plays a critical role in vesicle f ormation at the plasma membrane during endocytosis in animal cells. Here we report the identification of a new dynamin homolog in Arabidopsis named Ar abidopsis dynamin-like 6 (ADL6). ADL6 is quite similar to dynamin I in its structural organization: a conserved GTPase domain at the N terminus, a ple ckstrin homology domain at the center, and a Pro-rich motif at the C termin us. In the cell, a majority of ADL6 is associated with membranes. Immunohis tochemistry and in vivo targeting experiments revealed that ADL6 is localiz ed to the Golgi apparatus. Expression of the dominant negative mutant ADL6[ K51E] in Arabidopsis protoplasts inhibited trafficking of cargo proteins de stined for the lytic vacuole and caused them to accumulate at the trans-Gol gi network. In contrast, expression of ADL6[K51E] did not affect traffickin g of a cargo protein, H+-ATPase:green fluorescent protein, destined for the plasma membrane. These results suggest that ADL6 is involved in vesicle fo rmation for vacuolar trafficking at the trans-Golgi network but not for tra fficking to the plasma membrane in plant cells.