Giardins are involved in parasite attachment to the intestinal mucosa and in the cytoskeletal disassembly and reassembly that marks the transition from infectious trophozoite to transmissible cyst. They may interact with other cytoskeletal proteins such as microtubules in the microribbons or crossbridges, to maintain the integrity of the ventral disk. Most likely in the edges of the ventral disk microribbons. Belongs to the annexin family. Giardin subunit alpha subfamily.