Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2047362 | European Journal of Protistology | 2008 | 5 Pages |
Exocytosis of extrusomes, secretory granules found in protozoa, is involved in prey capture by the heliozoon Actinophrys sol. Here, we show that extracellular Ca2+ is necessary for exocytosis and prey capture in A. sol. We found that A. sol could not capture prey cells in a Ca2+-free solution. L-type Ca2+ channel blockers and a calmodulin antagonist also inhibited the capture of prey. These results suggest that Ca2+ influx via L-type Ca2+ channels plays a crucial role in exocytosis in A. sol. Concanavalin A (Con A) also inhibited prey capture, and the inhibition was relieved by the addition of its hapten sugar, α-mannoside, suggesting that Con A-binding glycoconjugates are implicated in exocytosis of extrusomes and the adhesion of prey cells.